| 1. |
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| 2. |
- Amcoff, Mirjam, et al.
(författare)
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Courtship signalling with a labile bilateral signal : males show their best side
- 2009
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 63:12, s. 1717-1725
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetries in courtship signals can result from both developmental instability during ontogeny and from temporary or permanent damage following mating, fighting, or interactions with predators. These two types of asymmetries, which can be divided into fluctuating asymmetry (FA) and damage asymmetry (DA), have both been suggested to play an important role in mate choice as potential honest indicators of phenotypic and/or genetic quality, while at the same time, DA may affect ornament asymmetry in a random manner. Interestingly, despite the massive research effort that has been devoted to the study of asymmetry during the past decades, very little is known about how an individual's behaviour relates to asymmetry. Here, we measure and characterise asymmetry in morphological courtship signals in Corynopoma riisei, a fish where males carry elaborate paddle-like appendices on each side of the body that they display in front of females during courtship. Moreover, we investigate whether male courtship display, employing this bilateral morphological trait, reflects trait asymmetry. Finally, we assess whether males respond to phenotypic manipulations of DA with corresponding changes in courtship behaviour. We show that male display behaviour is asymmetric in a manner that reflects asymmetry of their morphological courtship trait and that male display behaviour responds to manipulations of asymmetry of these paddles. Our results thus suggest that males preferentially use their best side and, hence, that males respond adaptively to temporary changes in signal trait asymmetry.
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| 3. |
- Andersson, Malte, 1941
(författare)
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Aposematism and crypsis in a rodent: antipredator defence of the Norwegian lemming
- 2015
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 69:4, s. 571-581
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Tidskriftsartikel (refereegranskat)abstract
- Aposematism is unusual in herbivorous mammals, and exceptions help clarify its ecology and evolution. The Norwegian lemming differs from other rodents in colouration and behaviour. One hypothesis is that its black, yellow and white colours, loud calls and ferocious defence reduce predation by conspicuous aposematism. Another hypothesis is that the colouration is cryptic. These alternatives are tested in a detectability experiment comparing lemmings and sympatric grey-sided voles. All 18 observers detected a higher proportion of the lemmings, corroborating conspicuousness. Unlike smaller rodents, Norwegian lemmings often call from a distance at predators. The aposematism hypothesis predicts that cryptically coloured Alaskan brown lemmings will not call. In the field, Norwegian lemmings gave antipredator calls at a human observer in 36 of 110 encounters, but brown lemmings did so in only 1 of 39 cases. Most Norwegian lemmings called if surprised within a few metres but froze or fled silently farther away, relying on crypsis against distant predators. Small juveniles called as often as adults, a possible case of auto-mimicry. In an earlier experiment, Norwegian lemmings, in contrast with grey-sided voles, aggressively resisted attacks by a major avian predator of rodents. The tests corroborate the hypotheses that (1) distinctive, contrast-rich colouration, antipredator calls and threat postures of the Norwegian lemming form a multimodal suit of aposematic traits, warning predators that this is a more dangerous prey than the smaller sympatric voles, and (2) discriminability from undefended species is an important adaptive reason for conspicuous distinctness of many aposematic signals.
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| 4. |
- Andrén, Maria Norevik, 1970, et al.
(författare)
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Filial cannibalism in a nest-guarding fish: females prefer to spawn in nests with few eggs over many
- 2014
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 68:10, s. 1565-1576
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Tidskriftsartikel (refereegranskat)abstract
- In fish, fecundity correlates with female body size and egg-tending males often eat small broods. Therefore, small females may prefer to spawn in nests that already contain many eggs, to ensure the brood is as large as possible. In contrast, large females may prefer nests with few eggs, if high egg number or density has a negative effect on egg survival, or if there are drawbacks of spawning last in a nest. To test the hypothesis that female body size affects nest (and male mate) choice, using the sand goby (Pomatoschistus minutus), we allowed small and large females to choose between two males that were matched in size—one guarding a small clutch and the other a large clutch, respectively. We recorded where females spawned (measure of female preference), the combined brood size, male courtship, egg care and nest building. We also quantified the effect of brood size and egg density on egg survival in a separate data set. Although the combined broods did not exceed the small brood sizes that are at risk of being eaten, both small and large females preferred to spawn in nests with smaller clutch sizes. This preference could not be explained by more courtship or male parental effort, nor by reduced survival of larger or denser broods. Instead, our result might be explained by females avoiding the danger of cannibalism of young eggs by males or the risk of reduced egg health associated with being near the nest periphery.
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| 5. |
- Araujo, Priscila, et al.
(författare)
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The role of visual and olfactory floral cues in twilight foraging by Ptiloglossa and Xylocopa bees
- 2024
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 78:2
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Tidskriftsartikel (refereegranskat)abstract
- Bees of Ptiloglossa and Xylocopa explore the chiropterophilous flowers of Pseudobombax longiflorum at twilight, but how the bees find the flowers in low light is unclear. In field experiments, we investigated if visual and olfactory floral cues are used by these bees to find P. longiflorum flowers, and which behaviors are triggered by these cues. While the crepuscular Ptiloglossa bees were more attracted to flowers with a combination of visual and olfactory cues than to isolated cues, the diurnal Xylocopa bees were equally attracted to the combination of visual and olfactory cues and to flowers with visual cues alone. Ptiloglossa bees visit the flowers under lower light intensity than Xylocopa bees. This indicates that the synergy between visual-olfactory cues facilitates flower detection in crepuscular bees. However, in higher light intensities, the large size of flowers with their broad spectrum reflectance may be enough to produce a reliable visual signal for the Xylocopa bees. Olfactory stimuli alone trigger only floral approaches in bees, while visual ones frequently trigger approaches followed by landings on flowers. This suggests that olfactory cues guide the bees to the flowers in twilight, but the presence of a visual cue is necessary to trigger landings and collection of floral resources.
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| 6. |
- Arct, Aneta, et al.
(författare)
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Benefits of extra-pair mating may depend on environmental conditions-an experimental study in the blue tit (Cyanistes caeruleus)
- 2013
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 67:11, s. 1809-1815
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Tidskriftsartikel (refereegranskat)abstract
- Extra-pair mating constitutes a relatively common reproductive strategy in many socially monogamous bird species. This strategy may considerably improve reproductive success of males, but female benefits from extra-pair matings still remain unclear and empirical evidence is scarce. This may be because genetic benefits of extra-pair mating are not always revealed. It is possible that they are shown only in unfavourable environmental conditions and hence problems arise with detecting differences between within- and extra-pair offspring whose performance is measured under favourable conditions. In order to test this prediction, we manipulated environmental conditions by altering brood sizes of blue tits and compared phenotypic characteristics of within- and extra-pair offspring in mixed-paternity broods. We found that extra-pair young exhibited a higher response to phytohemagglutinin in comparison to within-pair young, but this was only observed among nestlings from experimentally enlarged broods. These results indicate that genetic benefits may interact with the environment, and thus benefits of extra-pair mating are likely to become visible only when conditions are relatively unfavourable.
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| 7. |
- Berger, David, et al.
(författare)
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Time stress, predation risk and diurnal-nocturnal foraging trade-offs in larval prey.
- 2008
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 62:10, s. 1655-1663
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Tidskriftsartikel (refereegranskat)abstract
- Insect larvae increase in size with several orders of magnitude throughout development making them more conspicuous to visually hunting predators. This change in predation pressure is likely to impose selection on larval anti-predator behaviour and since the risk of detection is likely to decrease in darkness, the night may offer safer foraging opportunities to large individuals. However, forsaking day foraging reduces development rate and could be extra costly if prey are subjected to seasonal time stress. Here we test if size-dependent risk and time constraints on feeding affect the foraging–predation risk trade-off expressed by the use of the diurnal–nocturnal period. We exposed larvae of one seasonal and one non-seasonal butterfly to different levels of seasonal time stress and time for diurnal–nocturnal feeding by rearing them in two photoperiods. In both species, diurnal foraging ceased at large sizes while nocturnal foraging remained constant or increased, thus larvae showed ontogenetic shifts in behaviour. Short night lengths forced small individuals to take higher risks and forage more during daytime, postponing the shift to strict night foraging to later on in development. In the non-seasonal species, seasonal time stress had a small effect on development and the diurnal–nocturnal foraging mode. In contrast, in the seasonal species, time for pupation and the timing of the foraging shift were strongly affected. We argue that a large part of the observed variation in larval diurnal–nocturnal activity and resulting growth rates is explained by changes in the cost/benefit ratio of foraging mediated by size-dependent predation and time stress.
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| 8. |
- Berglund, Anders, et al.
(författare)
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Food or sex : males and females in a sex role reversed pipefish have different interests
- 2006
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 60:2, s. 281-287
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Tidskriftsartikel (refereegranskat)abstract
- In a sex role reversed pipefish, Syngnathus typhle, we found that basic life history allocations were directly influenced by sexual selection. We investigated time allocation to foraging and mating, respectively, in a choice experiment, giving males and females, of small or large body size, a choice between food and a potential partner. We found that males were more interested in foraging than mating, i.e., were more frequently observed in front of the food than in front of the partner, whereas females were more interested in the potential partner. This reflects sexual selection operating differently on the two sexes, as males and females are relatively similar in other life history traits, such as growth, mortality, age of maturity, dispersal, and parental expenditure. Moreover, large individuals allocated more time to mating activities, small to feeding. Individuals more interested in mating compared to food were subsequently more critical when given a choice between a large (high-quality) and a small (low-quality) partner, whereas individuals more interested in food were not selective. These findings are consistent with our predictions: sex-role reversed males can be relatively sure of achieving one or more matings, and should allocate more time to feeding and, hence, to parental investment, growth and/or future reproduction. Females, on the other hand, have more uncertain mating prospects and should allocate time to imminent reproductive activities, thereby foregoing other life history traits such as growth and future egg production. By this, they also sacrifice future fecundity and attractiveness.
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| 9. |
- Berglund, Anders, et al.
(författare)
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Male limitation of female reproductive success in a pipefish : effects of body-size differences
- 1990
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 27:2, s. 129-133
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Tidskriftsartikel (refereegranskat)abstract
- In the pipefish Syngnathus typhle, a species with exclusive male parental care, males limit female reproductive success because of their limited brood pouch space and long pregnancy. Sexual size dimorphism is absent in these 1-year-old animals but increases with age so that older females are larger than similarly aged males. Because fecundity is related to size in both sexes and increases more rapidly with body size in females than in males, the difference in growth increases female fecundity more, relative to male fecundity, as the fish get older. We therefore predicted that male limitation of female reproductive success is even more severe when all age classes are considered. To measure a female's maximum reproductive rate, she was provided with three males. Small 1-year-old females produced as many eggs, or produced eggs at the same rate, as a male of similar size could care for. Small females filled on average 1.06 males within the time span of one male pregnancy and actually produced on average 10 eggs fewer than needed to fill a similarly sized male. Large 2-year-old females, in contrast, produced on average a surplus of 149 eggs and filled 2.7 similarly sized males within the course of one pregnancy. The difference between females of the two size classes was highly significant. Males prefer to mate with larger females if given a choice. In nature sex ratios are equal, and males limit female reproductive success in the whole population. Therefore, small females are more severely constrained by mate availability than are larger females because males choose to mate with larger females.
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| 10. |
- Berglund, Anders, et al.
(författare)
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Mate choice, fecundity and sexual dimorphism in two pipefish species (Syngnathidae)
- 1986
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 19:4, s. 301-307
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Tidskriftsartikel (refereegranskat)abstract
- In order to understand the causes of sexual dimorphism, mate choice and size-related fecundity were studied in two pipefish species, Syngnathus typhle and Nerophis ophidion. Sexual dimorphism is more pronounced in N. ophidion; females are larger, have sexual colourings, and are more active during courtship. In S. typhle the sexes are alike in all these respects. Males brood their offspring in both species. In N. ophidion fecundity was positively correlated with both body size and the amount of sexual colouring in females. In males no correlation between body size and fecundity, or between body size and embryo size existed. Predictably, in mate choice experiments with equal-sized females, males chose females with more extensive sexual colourings. We explain sexual dimorphism in this species as a consequence of both natural selection (fecundity increases with size in females but not in males) and sexual selection (males prefer larger females). We argue that sexual size dimorphism did not evolve by selection minimizing overlap in food niches between the sexes, because food production is high in the Zostera beds where the fishes live, and no size dimorphism was found in the sympatrically occurring S. typhle. Furthermore, in N. ophidion dimorphism is not greater in a particular mouth character than in overall body size. In S. typhle egg size and the average number of eggs transferred per spawning were positively correlated with female body size. Apparently more energy per offspring was provided by larger males than by smaller males, and larger males also carried more offspring. As predicted, large mates were preferred by both sexes in mate choice experiments. This is explicable in terms of both natural selection (fecundity increases with size in both sexes) and sexual selection (both sexes prefer large mates). As a consequence of selection acting in the same direction in both sexes, sexual dimorphism is absent in S. typhle.
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| 11. |
- Berglund, Anders, et al.
(författare)
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Ornamentation predicts reproductive success in female pipefish
- 1997
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 40:3, s. 145-150
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Tidskriftsartikel (refereegranskat)abstract
- In the sex-role reversed pipefish Syngnathus typhle females compete for access to males and males are choosy. Females develop a temporary ornament when competing over mates with other females and when performing nuptial dances with males. This ornament is an amplification of the normal striped pattern in these fishes. We here show experimentally that (1) the contrast of this normal pattern forecasts the extent to which the ornament is shown, (2) contrast and ornamentation honestly signal female quality (egg numbers), (3) contrast and ornamentation accurately predict female mating success, (4) contrast is a phenotypically plastic trait specifically exaggerated under situations of female - female competition, and (5) neither contrast nor ornament. are energetically expensive to the females (i.e., they are independent of short-term nutritional status). Hence, as predicted in sex-role reversed species, ornament design is constrained by costs to female fecundity: an energetically demanding ornament would impair on a female's ability to produce eggs. The type of ornament described here is the expected one, costly for reasons other than being energetically expensive to produce.
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| 12. |
- Berglund, Anders, et al.
(författare)
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Selective males and ardent females in pipefishes
- 1993
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 32:5, s. 331-336
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Tidskriftsartikel (refereegranskat)abstract
- In the pipefishes Syngnathus typhle and Nerophis ophidion, males have been shown to limit female reproductive rate, and females to compete for access to males. Hence, these species fit the criteria for sex-role reversal. Males brood the eggs and provide the offspring with nutrients, oxygen and an osmoregulated environment. Moreover, in S. typhle both sexes prefer a larger mate when given a choice. Sexual selection theory predicts that males should be more '' choosy '' than females, and that was experimentally demonstrated in this study. We predicted that S. typhle males should be less eager to copulate than S. typhle females with an unattractive (i.e. small) mate. We measured eagerness as the time from the start of the experiment until copulation occurred. Males with unattractive partners took significantly longer to copulate than females with unattractive partners. Moreover, females invariably initiated the courtship dance, and resumed it quicker after copulation than did the males, again suggesting ''reproductive hesitation'' in males. Neither male nor female size per se was correlated with time until copulation. In N. ophidion, where we have previously shown that males prefer larger to smaller females, we found that females did not select males with regard to size. Our results are consistent both with earlier findings (males limit female reproduction and females compete for males) and with operational sex ratios in nature: in seven annual field samples in June, the numbers of S. typhle females with ripe eggs always significantly exceeded numbers of receptive males. Hence, the potential cost of being choosy in terms of lost matings is much higher in females than in males. In conclusion, S. typhle females were somewhat choosy, but less so than males, whereas N. ophidion females were not choosy at all.
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| 13. |
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| 14. |
- Beveridge, Darcy, et al.
(författare)
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Weak evidence that asset protection underlies temporal or contextual consistency in boldness of a terrestrial crustacean
- 2022
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 76:7
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, many studies have investigated the potential state dependence of individual differences in behaviour, with the aim to understand the proximate and ultimate causes and consequences of animal personality. Among the potential state variables that could affect behavioural expression is size and mass, but few studies have found associations at the among-individual levels. Insufficient sampling and incorrect analysis of data are cited as impediments to detecting correlations, if they exist. Here, we conducted a study using 100 pillbugs (Armadillidium vulgare) and assayed their defensive behaviour 24 times each over time and across familiarity contexts, to test the asset protection hypothesis that predicts a negative correlation between boldness and mass, and with increases in mass over time. Multivariate mixed models revealed that despite mostly consistent individual behavioural differences over time (modest slope variance) and across contexts (near-parallel reaction norms), and 18-fold range in starting mass, there was no correlation between individual mean mass and boldness. However, individuals that gained more mass over time may have been more ‘shy’ compared to those gaining less mass, but the correlation was weak and observed variation in mass gain was small. There was also a mean level trend of increasing shyness over time that was coincident with mean level mass increases over time. Together, our study provides weak evidence for the asset protection hypothesis, whereby individuals that accumulate more resources are thought to protect them through risk averse behaviour.
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| 15. |
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| 16. |
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| 17. |
- Blake, Chelsea A., et al.
(författare)
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Conspecific boldness and predator species determine predation-risk consequences of prey personality
- 2018
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer-Verlag New York. - 0340-5443 .- 1432-0762. ; 72:8, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Individual variation in the behavior of prey can influence predation risk in complex ways. We ran individual roach (Rutilus rutilus), a common freshwater fish, through a standard refuge emergence protocol to characterize their boldness, a key animal personality trait. We then paired a bold and a shy roach and exposed the pair to one of two predator species that have contrasting hunting modes to ascertain how personality traits shaped their survival during predator encounters. When a paired bold and shy prey fish interacted with a perch predator (active foraging mode), bold and shy prey were consumed in almost equal numbers. However, pike predators (ambush foraging mode) selectively consumed more shy prey, and prey body size and boldness score both contributed significantly to which prey fish was eaten. Our findings support the idea that multiple predators with different foraging modes, and hence differential selection on prey personality, could contribute to maintaining variation in personality in prey populations. Furthermore, for social species, including shoaling fish, the ultimate consequences of an individual’s personality may depend upon the personality of its nearby conspecifics. Significance statement: Animals of the same species often look similar, but individuals show differences in their behavior that can have important consequences, for instance when these individuals interact with predators. The common roach is a freshwater fish that shows inter-individual variation in its propensity to take risks, a key personality trait often termed boldness. Variation in boldness may affect the outcome when roach interact with predators, i.e., if they get eaten or survive. However, we found the impact of roachs’ personality type depends on what species of predatory fish they face. When we put a shy and a bold roach together with predatory perch, the roachs’ personality did not significantly affect which individual was eaten. But when the predator was a pike, the predators selectively ate more shy roach, and the likelihood an individual would be eaten depended on their body size.
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| 18. |
- Bonato, Maud, et al.
(författare)
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Growth rate and hatching date in ostrich chicks reflect humoral but not cell-mediated immune function
- 2009
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 64:2, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- A tradeoff between immune response and life history traits, in particular growth rate, has been documented in various bird species. Ostriches are fast-growing birds and a typical feature of cohorts is that offspring often differ greatly in size. We investigated the relationship between hatching date and growth rate of chicks and both cell-mediated (measured using a phytohaemagglutinin (PHA) injection) and humoral immune responses in ostrich chicks maintained on a research farm. Chicks with higher growth rates had intermediate responses to both diphtheria and tetanus toxoids. By contrast, no relation between growth rates and responses to PHA injection were found. We conclude that chick growth rate variation may be explained beyond a certain threshold by a tradeoff between the humoral response and growth. Both responses to PHA injection and humoral responses in chicks were found to decrease with chick hatching date. Within the context of ostrich farming, these results could partially explain size variations observed in cohorts of chicks, as well as high mortality rates during their first 3 months of age.
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| 19. |
- Bonato, Maud, et al.
(författare)
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Ostrich chick humoral immune responses and growth rate are predicted by parental immune responses and paternal colouration
- 2013
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 67:12, s. 1891-1901
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Tidskriftsartikel (refereegranskat)abstract
- One of the most important measures of offspring performance is growth rate, which is often traded off against another important survival trait, immune function. A particular feature of ostrich chicks maintained in farmed environments is that cohorts of chicks vary widely in size. As parents can have a profound effect on the phenotype and fitness of their offspring, we investigated whether chick growth and immune defence were related to variation in levels of immune defence in their genetic parents. As secondary sexual traits of sires could serve as indicators of male quality, and be used in female mating decisions, we also investigated whether chick growth rate and immune defence were related to male plumage and integumentary colouration. We found that offspring growth rates and humoral responses were related to the humoral responses of their parents, suggesting that at least some components of humoral immune capacity are heritable. The white colour of male ostrich feathers was correlated to the humoral response and growth rate of their offspring, suggesting that this visual cue involved in the male courtship display could serve as an important signal to females of male quality, thereby forming the basis of mate choice in this species.
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| 20. |
- Boström, Jannika, et al.
(författare)
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Autumn migratory fuelling : a response to simulated magnetic displacement in juvenile wheatears, Oenathe oenathe
- 2010
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 64:11, s. 1725-1732
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Tidskriftsartikel (refereegranskat)abstract
- Recent experiments exposing migratory birds to altered magnetic fields simulating geographical displacements have shown that the geomagnetic field acts as an external cue affecting migratory fuelling behaviour. This is the first study investigating fuel deposition in relation to geomagnetic cues in long-distance migrants using the western passage of the Mediterranean region. Juvenile wheatears (Oenanthe oenanthe) were exposed to a magnetically simulated autumn migration from southern Sweden to West Africa. Birds displaced parallel to the west of their natural migration route, simulating an unnatural flight over the Atlantic Ocean, increased their fuel deposition compared to birds experiencing a simulated migration along the natural route. These birds, on the other hand, showed relatively low fuel loads in agreement with earlier data on wheatears trapped during stopover. The experimental displacement to the west, corresponding to novel sites in the Atlantic Ocean, led to a simulated longer distance to the wintering area, probably explaining the observed larger fuel loads. Our data verify previous results suggesting that migratory birds use geomagnetic cues for fuelling decisions and, for the first time, show that birds, on their first migration, can use geomagnetic cues to compensate for a displacement outside their normal migratory route, by adjusting fuel deposition.
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| 21. |
- Boström, Jannika, et al.
(författare)
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Northern magnetic displacements trigger endogenous fuelling responses in a naive bird migrant
- 2012
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 66:5, s. 819-821
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, we found that juvenile northern wheatears (Oenanthe oenanthe) exposed to a magnetic displacement to the west of their natural migration route increased their body mass. The total intensity and inclination used for the western displacement may also have been interpreted as northern compared to the experimental site (stronger total field intensity and steeper inclination angle). In order to investigate whether the fuelling response was a response to an unexpected magnetic field or specific to the northern magnetic field, we conducted a new experiment. Juvenile wheatears from the same study population were magnetically displaced to southwestern magnetic fields, exposing the birds to unexpected magnetic combinations, but eliminating the possible effect of a northern magnetic field. A control group was kept in the local geomagnetic field in Sweden for comparison. There was no difference in body mass increase between treatments, suggesting that the fuelling response previously found was not a simple response to an unexpected magnetic field, but rather a specific response to the northern magnetic field. Juvenile wheatears may have developed a fuelling response to northern magnetic fields in order to enable a successful flight towards the migration goal.
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| 22. |
- Botterill-James, Thomas, et al.
(författare)
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Experimental manipulation suggests effect of polyandry but not mate familiarity on within-pair aggression in the social skink, Liopholis whitii
- 2017
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 71:4
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Long-term monogamy is a key characteristic of family living across animals. The evolutionary maintenance of long-term monogamy has been suggested to be facilitated by increased reproductive coordination as a result of mate familiarity, leading to increased reproductive success. However, such effects can be compromised if females mate outside the pair bond (e.g. female polyandry), introducing conflicts of interest between the male and female. Here, we experimentally test the effects of both mate familiarity and female polyandry on agonistic behaviour and reproduction in a family living lizard, Liopholis whitii. We found that mate familiarity did not decrease the level of aggression between pairs whereas reducing female polyandry did. However, we did not find an effect of either mate familiarity or female polyandry on female reproductive output. These results suggest that male behavioural responses to female polyandry may influence pair stability in Liopholis whitii, providing support for the growing appreciation of the multiple ways in which female polyandry can influence the stability of family living. Significance statement: Family living is underpinned by social pair bonds between adults (i.e. stable social monogamy). Therefore, key to understanding the emergence and maintenance of family living is identifying factors influencing pair bonds. We manipulated both female polyandry and mate familiarly in replicated enclosure experiment using social lizards to test their role in mediating within-pair aggression and ultimately the coordination of reproductive behaviour and hence reproductive output. We found that polyandry but not mate familiarity influenced levels of aggression between pairs but this did not transmit into concomitant effects on reproductive output.
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| 23. |
- Brlík, Vojtěch, et al.
(författare)
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Population-specific assessment of carry-over effects across the range of a migratory songbird
- 2020
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 74:12
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Annual cycle events may be interlinked, influence following annual cycle stages, and may alter performance of individuals. Such links, called carry-over effects, can explain individual variation in timing or reproductive success in migratory species. Identifying the key links affecting fitness may reveal the mechanisms of species population dynamics but the current evidence for the strongest carry-over effects is equivocal. Here, we aim to assess the carry-over effects in great reed warblers Acrocephalus arundinaceus, a long-distance migratory songbird, using 103 full-annual tracks from three European and two Asian breeding populations. Our results showed strong positive relationships within autumn and spring migration periods and buffering capacity of the non-breeding period preventing events to carry over between these periods. Moreover, we found no profound relation between the non-breeding habitat quality or seasonality (quantified using stable isotopes and remote sensing data) and the timing of spring migration. The strongest carry-over effects occurred in individuals from the southern European breeding population compared to the northern and the central European populations. A moderate relationship between the habitat seasonality during moult and the spring migration timing indicates the importance of the complete moult. The overall weak carry-over effects of non-breeding habitat conditions found in this study contrast with previous results and imply between-species differences in these crucial relationships. Moreover, the population-specific carry-over effects highlight the importance of multi-population approach and advise caution in interpretation of results from single-population studies. Finally, the carry-over effect from the moulting period indicates the significance of a so-far neglected link in the species. Significance statement: Environmental conditions vary in space and time. Therefore, migratory species adjust the timing of migration in order to maximise their fitness. However, the links between annual cycle events in multiple populations and the consequences of environmental conditions outside the breeding range are scarcely known. In this study, we used tracking data of the great reed warbler, an insectivorous bird species breeding across western Eurasia and wintering in Africa, to study a complex system of links between annual events. We found that the strength of these links differed between geographically distinct populations but not between sexes. Moreover, harsh environmental conditions during moult delayed the timing of subsequent events. Our findings could help explain large-scale differences in population size changes observed in some species and highlight the importance of energetically demanding moult period for the life of migratory species. Finally, our results demonstrate the need for multi-population approach in studies on seasonal interactions.
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| 24. |
- Brodin, Anders, et al.
(författare)
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Interspecific observational memory in a non-caching Parus species, the great tit Parus major
- 2014
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 68:4, s. 649-656
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Tidskriftsartikel (refereegranskat)abstract
- Scatter-hoarding passerine birds have become a model system for research on spatial memory capacity. This research has focussed on two families, the Corvidae (crows, jays, nutcrackers, etc.) and the Paridae (titmice and chickadees). Corvids are considered to have highly developed cognitive skills that sometimes have been compared with the great apes. Even though pilfering, or stealing of caches made by others, is common among scatter-hoarding birds, the ability to memorize positions of caches made by others has only been demonstrated in some species of corvids. In parids, the ability to memorize positions of caches made by others has not been demonstrated. In a laboratory experiment, we allowed caged great tits to observe caching marsh tits and found that they remembered caching locations both 1 and 24 h after observation. This is the first time observational spatial learning of this type explicitly has been demonstrated in a parid. This ability is surprising since the great tit is not itself a food hoarder, meaning that it may not have the special memory adaptations in the brain that specialized food hoarders possess. Also, the memorization process in an observing pilferer may differ from the memorization that hoarders make of own caches. For example, the typical close inspection of the cache that hoarding parids do after caching will usually not be possible from a distance. Also, the visual perspective of the observing scrounger may be different from that of the hoarder, meaning that some understanding of allocentric space may be required.
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| 25. |
- Brodin, Anders, et al.
(författare)
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Rank-dependent hoarding effort in willow tits (Parus montanus): a test of theoretical predictions
- 2003
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 54:6, s. 587-592
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Tidskriftsartikel (refereegranskat)abstract
- Many birds and mammals store energy as hoarded food supplies. A supply of stored food is beneficial during periods when food is scarce, but building up and managing such a supply also entails costs. The optimal number of caches will be reached when the net benefit is at its maximum. If dominants can steal more stored food from subordinates than the other way around, the optimum will differ between these categories. A previous theoretical model of hoarding in groups with dominant and subordinate members produced three testable predictions: (1) hoarders should store more food as anticipated future conditions get worse; (2) subordinate flock members should store more food than dominants; and (3) dominants should increase hoarding relatively more than subordinates as conditions get worse. Here we present a field experiment on willow tits (Parus montanus) designed to test these predictions. We found support for all three. Hoarding increased as conditions got worse, subordinates stored at a higher rate than dominants, and dominants increased their hoarding effort relatively more than subordinates as conditions worsened. These results support the incorporation of information on dominance and food availability into models predicting food storage behaviour.
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| 26. |
- Brodin, Anders, et al.
(författare)
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Sex differences in learning ability in a common songbird, the great tit-females are better observational learners than males
- 2015
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 69:2, s. 237-241
-
Tidskriftsartikel (refereegranskat)abstract
- In mammals, including humans, the most consistent cognitive sex difference appears to be a male advantage in spatial ability. Usually, some sex-correlated selective advantage is inferred to explain this, for example, the need for males to navigate over large territories. In birds, sex differences in learning abilities are rare. Here, we show that females of a common European songbird, the great tit, do clearly better than males in an observational memorization task. We allowed caged great tits to observe food-caching marsh tits in an indoor aviary. One hour later, the great tits were released to search for the cached food. Females consistently performed better than males in this task. The results are remarkable for several reasons: (i) a sex difference in a cognitive ability of such a magnitude is unusual; (ii) most sex differences in spatial ability that have been reported so far concerns a male advantage; and perhaps most remarkably, (iii) female great tits were as successful in relocating the cached food as the hoarding marsh tits themselves. We hypothesize that female great tits are better at this than males because they are subordinate foragers. Males have prior access to food in nature and can easily displace females. Females will then benefit from a special ability to memorize caching positions that makes it possible for them to return and retrieve the food later when males are not around.
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| 27. |
- Brodin, Tomas, et al.
(författare)
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Personality trait differences between mainland and island populations in the common frog (Rana temporaria)
- 2013
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 67:1, s. 135-143
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding and predicting species range expansions is an important challenge in modern ecology because of rapidly changing environments. Recent studies have revealed that consistent within-species variation in behavior (i.e., animal personality) can be imperative for dispersal success, a key process in range expansion. Here we investigate how habitat isolation can mediate differentiation of personality traits between recently founded island populations and the main population. We performed laboratory studies of boldness and exploration across life stages (tadpoles and froglets) using four isolated island populations and four mainland populations of the common frog (Rana temporaria). Both tadpoles and froglets from isolated populations were bolder and more exploratory than conspecifics from the mainland. Although the pattern can be influenced by possible differences in predation pressure, we suggest that this behavioral differentiation might be the result of a disperser-dependent founder effect brought on by an isolation-driven environmental filtering of animal personalities. These findings can have important implications for both species persistence in the face of climate change (i.e., range expansions) and ecological invasions as well as for explaining rapid speciation in isolated patches.
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| 28. |
- Buatois, Alexis, 1989, et al.
(författare)
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A comparative analysis of foraging route development by bumblebees and honey bees
- 2024
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 78:1
-
Tidskriftsartikel (refereegranskat)abstract
- Many pollinators, such as bees, hummingbirds and bats, use multi-destination routes (traplines) to exploit familiar plant resources. However, it is not clear to what extent the mechanisms underpinning trapline development and optimisation are comparable across species. Here we compared route formation, repeatability and efficiency by foragers of two social bee species, the solo foraging bumblebee Bombus terrestris and the mass foraging honey bee Apis mellifera, in the same laboratory conditions. In a simple routing task (with four artificial flowers), all bumblebees and honey bees developed a route, although honey bees were slower to do so. In a more complex routing task (with six flowers), however, only bumblebees developed a route between the 6 flowers. Honey bees took a longer time to discover all flowers and developed routes between fewer flowers. Comparing bumblebees and honey bees using the same experimental paradigm thus revealed key behavioural differences likely resulting from their contrasting collective foraging strategies.
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| 29. |
- Buhl, Jerome, et al.
(författare)
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Shape and efficiency of wood ant foraging networks
- 2009
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 63:3, s. 451-460
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Tidskriftsartikel (refereegranskat)abstract
- We measured the shape of the foraging trail networks of 11 colonies of the wood ant Formica aquilonia (Formica rufa group). We characterized these networks in terms of their degree of branching and the angles between branches, as well as in terms of their efficiency. The measured networks were compared with idealized model networks built to optimize one of two components of efficiency, total length (i.e., total amount of trail) and route factor (i.e., average distance between nest and foraging site). The analysis shows that the networks built by the ants obtain a compromise between the two modes of efficiency. These results are largely independent of the size of the network or colony size. The ants' efficiency is comparable to that of networks built by humans but achieved without the benefit of centralized control.
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| 30. |
- Choi, Seoyun, et al.
(författare)
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Parent personality is linked to juvenile mortality and stress behavior in the arctic fox (Vulpes lagopus)
- 2019
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 73:12
-
Tidskriftsartikel (refereegranskat)abstract
- Life history theory predicts that individuals will differ in their risk-taking behavior according to their expected future fitness. Understanding consequences of such individual variation within a behavioral trait is crucial in explaining potential trade-offs between different traits and in predicting future dynamics in changing environments. Here, we studied individuals in a wild arctic fox population to explore if (1) individual variation in risk-taking behaviors of adult arctic foxes and in stress-dealing behaviors of their juveniles exist and are consistent over time to verify the existence of personality traits; (2) those behavioral traits in adults and juveniles are correlated; (3) they can explain fitness-related components (i.e., juvenile physical condition, mortality rate). We presented simple field experiments assessing behavioral traits by observing adult reactions toward approaching observers, and juvenile behaviors while trapping. Through the experiments, we found highly consistent individual variation of adults in vigilance and boldness levels, and more flexible juvenile behavioral traits categorized as investigating, passive, and escaping. The offspring of bolder adults exhibited more investigating behaviors and were less passive than the offspring of shy adults. Juvenile physical condition was not related to their mortality nor any behavioral traits of either parents or themselves. Lastly, highly investigating and active juveniles with bold parents had significantly lower mortality rates. This shows that interactions between parent personality and juvenile behavioral traits affect a fitness-related component in the life history of individuals. Significance statement The recent surge of interest in consistent individual difference in behavior, also called as animal personality, has already focused on its fitness consequences, but few studies have investigated the interactions between parent and offspring personality, and their ecological consequences. Moreover, this has rarely been studied in wild canids. The arctic fox is a charismatic species showing wide individual variation in behaviors. They live in highly fluctuating tundra ecosystems providing different selection regimes, making it even more eco-evolutionarily intriguing. Yet, few studies looked into behavioral traits and their importance in this system. While introducing simple methods to improve personality research in the wild, we provide a unique example of how variation in both parents and their juveniles collectively works for group dynamics in a cyclic population. This provides a firm basic for understanding behavior-mediated dynamics and opens up broader questions on how fluctuating environments exert varying pressures on individual differences.
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| 31. |
- Corral-López, Alberto, et al.
(författare)
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On the role of body size, brain size, and eye size in visual acuity
- 2017
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 71:12
-
Tidskriftsartikel (refereegranskat)abstract
- The visual system is highly variable across species, and such variability is a key factor influencing animal behavior. Variation in the visual system, for instance, can influence the outcome of learning tasks when visual stimuli are used. We illustrate this issue in guppies (Poecilia reticulata) artificially selected for large and small relative brain size with pronounced behavioral differences in learning experiments and mate choice tests. We performed a study of the visual system by quantifying eye size and optomotor response of large-brained and small-brained guppies. This represents the first experimental test of the link between brain size evolution and visual acuity. We found that female guppies have larger eyes than male guppies, both in absolute terms and in relation to their body size. Likewise, individuals selected for larger brains had slightly larger eyes but not better visual acuity than small-brained guppies. However, body size was positively associated with visual acuity. We discuss our findings in relation to previous macroevolutionary studies on the evolution of brain morphology, eye morphology, visual acuity, and ecological variables, while stressing the importance of accounting for sensory abilities in behavioral studies.
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| 32. |
- Cramer, Emily R. A., et al.
(författare)
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Testing a post-copulatory pre-zygotic reproductive barrier in a passerine species pair
- 2014
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 68:7, s. 1133-1144
-
Tidskriftsartikel (refereegranskat)abstract
- Sexual selection may drive speciation, but most research focuses on pre-copulatory sexual selection, overlooking post-copulatory processes. Post-copulatory sexual selection in allopatric populations could drive divergence in post-copulatory pre-zygotic (PCPZ) phenotypes, limiting gene flow upon secondary contact. Here, we performed in vitro experiments examining one potential PCPZ barrier between two closely related passerine species, house sparrows (Passer domesticus) and Spanish sparrows (Passer hispaniolensis). In birds, crossing in the vagina may be particularly challenging for sperm, so we tested the effect of female reproductive tract fluids on sperm swimming speed and motility. If a PCPZ barrier exists at this stage of the fertilization process, heterospecific female fluids are predicted to reduce sperm swimming speed or motility relative to conspecific female fluid. We found that house sparrow female fluids affected the two species' sperm asymmetrically, depending on the control sperm velocity and male species. Overall, however, sperm performed equally in conspecific and heterospecific female fluids, and the species had similar sperm morphology and sperm swimming performance. Low divergence in PCPZ phenotypes between species, perhaps because post-copulatory sexual selection is stabilizing or only moderately strong in these taxa, may be insufficient to cause an overall PCPZ barrier. Reinforcement may be unlikely to drive PCPZ barriers for this species pair, because relatively effective pre-copulatory barriers exist between the species, and because hybrids can be quite successful. Testing the role of PCPZ barriers in birds with more divergent PCPZ phenotypes will improve our understanding of speciation in passerines.
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| 33. |
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| 34. |
- Delingat, Julia, et al.
(författare)
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Obligatory barrier crossing and adaptive fuel management in migratory birds: the case of Atlantic crossing in Northern Wheatears
- 2008
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 62:7, s. 1069-1078
-
Tidskriftsartikel (refereegranskat)abstract
- Behaviour on migration was often suggested to be selected for time-minimising strategies. Current optimality models predict that optimal fuel loads at departure from stopover sites should increase with increasing fuel deposition rates. We modified such models for the special case of the east Atlantic crossing of the Northern Wheatear (Oenanthe oenanthe). From optimality theory, we predict that optimal time-minimising behaviour in front of such a barrier should result in a positive correlation between fuel deposition rates and departure fuel loads only above a certain threshold, which is the minimum fuel load (f(min)) required for the barrier crossing. Using a robust range equation, we calculated the minimum fuel loads for different barrier crossings and predict that time-minimising wheatears should deposit a minimum of 24% fuel in relation to lean body mass (m (0)) for the sea crossing between Iceland and Scotland. Fuel loads of departing birds in autumn in Iceland reached this value only marginally but showed positive correlation between fuel deposition rate (FDR) and departure fuel load (DFL). Birds at Fair Isle (Scotland) in spring, which were heading towards Iceland or Greenland, were significantly heavier and even showed signs of overloading with fuel loads up to 50% of lean body mass. Departure decisions of Icelandic birds correlated significantly with favourable wind situations when assuming a migration direction towards Spain; however, the low departure fuel loads contradict a direct non-stop flight.
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| 35. |
- Dijk, Ben, et al.
(författare)
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Is one defence enough? : Disentangling the relative importance of morphological and behavioural predator-induced defences
- 2016
-
Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 70:2, s. 237-246
-
Tidskriftsartikel (refereegranskat)abstract
- Many organisms show predator-induced behavioural and morphological phenotypic plasticity. These defence mechanisms are often expressed simultaneously. To estimate the relative importance of these two defences, we conducted a laboratory experiment using tadpoles of the common frog (Rana temporaria) as prey and Aeshna dragonfly larvae as predators. We first raised tadpoles in the presence and absence of caged predators to induce differences in defensive morphology, and then conducted free ranging predator trials in environments that were either with or without the presence of predation cues to induce differences in defensive behaviour. This 2 x 2 design allowed us to separate the effects of inducible morphology from inducible behaviour. Caged predators induced deeper bodies and tailfins and reduced activity levels in tadpoles. The time to first capture was shortest in tadpoles without morphological or behavioural defences. Tadpoles with a behavioural defence had a significantly longer time to first capture. Tadpoles with only antipredator morphology tended to have a longer time to first capture as compared to those without any induced defences. This treatment also had a higher number of injured tadpoles as compared to other treatments, suggesting that inducible morphology facilitates predator escape due to the 'lure effect'. However, tadpoles with both behavioural and morphological defences did not have a longer time to first capture as compared to tadpoles with only morphological or behavioural induced defences. Our results suggest that both behavioural and morphological antipredator responses contribute to reduced capture efficiency by predators, but their simultaneous expression did not have any additive effect to the time of first capture and survival, and that the morphology response is most effective when tadpoles are active.
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| 36. |
- Dussutour, Audrey, et al.
(författare)
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Collective decisions in ants when foraging under crowded conditions
- 2006
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 61, s. 17-30
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we examine the effect of crowding on the selection of a path in the mass-recruiting ant Lasius niger. In our experiment, ants had to go from their nest to a food source by crossing a diamond-shaped bridge, giving the choice between two paths. Two types of bridges were used: the first had two branches of equal length but different width while the second had two branches of different length and width. Experiments at high traffic volume always ended up with the selection of the wider branch, even if it was longer. This result shows that overcrowding on the narrow branch plays an essential role in the mechanism underlying the choice of route in ants. A mathematical model was developed to evaluate the importance of two mechanisms that could account for this result. The first is based on the difference in travel duration between the two paths. The second is based on the repulsive interactions between workers making head-on encounters. The model shows that travel duration per se is not sufficient to explain path choice. Rather, it is the interplay between trail following behaviour and repulsive interactions that allows ants to choose the path that minimizes their travel time. When choosing a path ants thus prefer to trade time against energy. Our results demonstrate that any environmental constraint that alters the dynamics of trail recruitment can lead to the emergence of adaptive foraging decisions without any explicit coding of information by the foragers at the individual level.
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| 37. |
- Dutour, Mylene, et al.
(författare)
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Great tit responses to the calls of an unfamiliar species suggest conserved perception of call ordering
- 2020
-
Ingår i: Behavioral Ecology and Sociobiology. - : SPRINGER. - 0340-5443 .- 1432-0762. ; 74:3
-
Tidskriftsartikel (refereegranskat)abstract
- Many species of birds produce distinct calls when mobbing predators. These calls often recruit nearby conspecifics and heterospecifics to help drive the predators away. In some species, such as members of the family Paridae, mobbing calls are composed of multiple elements that seem to follow a characteristic order. Previous work in parids demonstrated that note ordering influences both the responses of conspecifics and some other co-occurring Paridae species. Cross-species sensitivity to note ordering could result from individuals' learning to associate individual heterospecific calls with threats or, rather, because the typical note orderings are shared across species. Here, we test these hypotheses by assessing the responses of European great tits (Parus major) to the naturally and artificially ordered calls of black-capped chickadees (Poecile atricapillus), a North American species. In response to the naturally ordered mobbing calls of chickadees, we found that great tits exhibit vigilance and rapidly approach the sound source, behaviors that were indistinguishable to those expressed in response to conspecific calls. If learned associations are necessary for sensitivity to note ordering, then a key prediction is that great tit responses to naturally ordered and artificially reversed chickadee calls should be similar (and weak). In contrast to this prediction, we found that great tits were less vigilant, but approach the sound source in response to artificially reversed chickadee calls. These findings suggest that perception of note ordering patterns is conserved. However, they are also in agreement with a "perception bias" hypothesis: that the first notes of the call mask the notes that follow them, preventing the receiver from perceiving the second part of the call. Although we provide evidence against perception bias, further research is needed to convincingly disentangle these two hypotheses.
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| 38. |
- Eklöv, Peter, et al.
(författare)
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SPECIES-SPECIFIC ANTIPREDATOR CAPACITIES AND PREY REFUGES - INTERACTIONS BETWEEN PISCIVOROUS PERCH (PERCA-FLUVIATILIS) AND JUVENILE PERCH AND ROACH (RUTILUS-RUTILUS)
- 1995
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 37:3, s. 169-178
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Tidskriftsartikel (refereegranskat)abstract
- The outcome of predator-prey interactions depends on the characteristics of predators and prey as well as the structure of the environment. In a replicated field enclosure experiment, we tested the effects of quantity and quality of different prey refuges (no structure, structure forming a partial refuge, and structure forming a complete refuge) on the interaction between piscivorous perch (Perca fluviatilis) and juvenile perch and roach (Rutilus rutilus). We quantified the behaviour of the predators and the prey and predator-induced prey mortality. The piscivores stayed in or close to the prey refuge and were more dispersed in the presence than in the absence of prey refuges. Survival of juvenile perch and roach decreased in the presence of predators and was higher for juvenile roach than for juvenile perch. In addition, juvenile perch survival increased with refuge efficiency. Roach formed schools which were denser in the presence of predators, had a higher swimming speed (both in the open water and in the refuge) and used a larger area than juvenile perch. Both prey species decreased their distance to the prey refuge and increased the proportion of their time spent in the refuge in the presence of predators. The number of switches between the open-water habitat and the prey refuge was higher for juvenile roach than for juvenile perch. Juvenile perch used different parts of the prey refuge in a flexible way depending both on presence of predators and refuge type whereas juvenile roach used the different parts of the prey refuge in fixed proportions over all refuge treatments. Our results suggest that juvenile roach had a overall higher capacity to avoid predation than juvenile perch. However, in the presence of qualitatively different prey refuges juvenile perch responded to predators with more flexible refuge use than juvenile roach. The differences in antipredator capacities of juvenile perch and roach when subjected to piscivorous perch predation may depend on differences in life history patterns of the two species.
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| 39. |
- Elmberg, Johan, 1960-
(författare)
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Factors affecting male yearly mating success in the common frog, Rana temporaria
- 1991
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. - 0340-5443 ; 28:2, s. 125-131
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Tidskriftsartikel (refereegranskat)abstract
- The mating behavior of the European common frog, Rana temporaria, was studied experimentally. Female body length was correlated with body mass as well as with fecundity. However, males showed no mating preference with regard to either female body length, body mass, or fecundity. In successive multiple matings, male readiness to re-mate as well as fertilization success did not vary among the first four matings. Further, fertilization success was not correlated with either the number of days since the previous fertilization, water volume in the experimental container, testes mass, female/male body length ratio, or female fecundity. However, there was a positive correlation between fertilization success and male fat reserve status. Sexual competition and mating patterns were studied in tanks in which operational sex ratio (OSR) and male density were manipulated, and time for sexual competition was allowed to vary. Successful take-overs and nonrandom mating (large male advantage) were observed only at a combination of a four-fold male bias in OSR and an unnaturally high male density (30-50/m2). I argue that in natural populations of Rana temporaria: (1) There is considerable intraspecific variation in the opportunity for sexual competition, (2) OSR influences mating pattern more than male density and time (duration of the prespawning period), and (3) nonrandom mating should be rare.
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| 40. |
- Esteban, R., et al.
(författare)
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Maternal kinship and fisheries interaction influence killer whale social structure
- 2016
-
Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 70:1, s. 111-122
-
Tidskriftsartikel (refereegranskat)abstract
- The primary prey of killer whales (Orcinus orca) in the Strait of Gibraltar is the bluefin tuna (Thunnus thynnus). All killer whales observed in this area hunt tuna by chasing individual fish until they become exhausted and can be overcome. However, a subset of pods also interact with a dropline tuna fishery which has developed since 1995. Here, we investigated the social structure within and among social units (pods). Our data suggested that social structure was shaped by maternal kinship, which appears to be a species-specific trait, but also by foraging behavior, which is less common at the intra-population level. At the start of the study, only one cohesive pod interacted with the fishery, which during the course of the study underwent fission into two socially differentiated pods. Social structure within these two fishery-interacting pods was more compact and homogenous with stronger associations between individuals than in the rest of the population. Three other pods were never seen interacting with the fishery, despite one of these pods being regularly sighted in the area of the fishery during the summer. Sociality can influence the spread of the novel foraging behaviors and may drive population fragmentation, which, in this example, is already a critically small community. Observations of social changes in relation to changes in foraging at the earliest stages of diversification in foraging behavior and social segregation may provide insights into the processes that ultimately result in the formation of socially isolated discrete ecotypes in killer whales.
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| 41. |
- Flanagan, Sarah P., et al.
(författare)
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Mate quality and the temporal dynamics of breeding in a sex-role-reversed pipefish, S. typhle
- 2017
-
Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 71:1
-
Tidskriftsartikel (refereegranskat)abstract
- The spatiotemporal dynamics of receptivity and breeding date, coupled with individual-level quality and attractiveness, are centrally important to mating system dynamics. These topics have been investigated in some detail in birds, but much less work has been devoted to other taxonomic groups, and almost no work has addressed spatiotemporal factors and individual quality in sex-role-reversed taxa. The broad-nosed pipefish, Syngnathus typhle, provides an excellent opportunity to investigate these ideas in a sex-role-reversed fish. Here, we addressed three questions related to mating dynamics in S. typhle: (1) Do higher-quality males arrive earlier on the breeding grounds and mate first? (2) Are early-breeding males in better condition than later-breeding males? And (3) do mating events involving higher-quality males produce better clutches than mating events involving lower-quality males? We collected data from a field study and a laboratory breeding experiment to address our hypotheses. Our results show that larger males mate earlier than smaller males and that pregnant males have higher measures of condition compared to non-pregnant males. Moreover, our laboratory results demonstrate that pairings between larger males and preferred females yielded more offspring than pairings involving smaller males. In summary, the spatiotemporal dynamics of S. typhle breeding patterns, combined with variation in individual quality, play an important role in shaping mating systems and should be incorporated in future analyses of mating behavior and sexual selection in this interesting sex-role-reversed pipefish. Significance statement The breeding patterns of a species can fluctuate over time due to a number of factors, one of which is individual quality. Although the effects of both the timing of reproduction and female quality on mating systems have been studied in some species, they have been investigated primarily in isolation. Here, we demonstrate that individual quality and the timing of reproduction interact to affect reproductive success in a wild population of sex-role-reversed fish.
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| 42. |
- Flink, Henrik, et al.
(författare)
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Nest size preferences and aggression in sand gobies (Pomatoschistus minutus)
- 2015
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer. - 0340-5443 .- 1432-0762. ; 69:9, s. 1519-1525
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Tidskriftsartikel (refereegranskat)abstract
- In animal competition, resource holding potential (RHP) and resource value are two important factors determining the level of aggression and the outcome of contests. One valuable resource among nest-brooding animals that is subject to intense competition is a suitable nest substrate. Sand goby males (Pomatoschistus minutus) rely on finding good nest substrates, but the strategies vary between regions. We first investigated the nest size preferences in sand gobies from Kalmar Sound, a brackish area of the Baltic Sea with a shortage of suitable shells for nest construction and few invertebrate nest predators. Males expressed clear preference for larger nest substrates regardless of the male’s own size. To manipulate resource value, we provided males with large or small nests and tested if this and/or RHP affected aggression during nest defence. Resource value (a preferred large nest vs an unpreferred small nest) had no effect on aggression. However, RHP (total length of the resident male) had a significant effect. Larger males were more aggressive than smaller ones when matched against an opponent of the same size, suggesting that resident males acted according to own RHP.
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| 43. |
- Forstmeier, W, et al.
(författare)
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Does song reflect age and viability? A comparison between two populations of the great reed warbler Acrocephalus arundinaceus
- 2006
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 59:5, s. 634-643
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Song complexity is often regarded as a sexually selected trait that reflects the overall quality of a male. In many passerine species, old males possess larger song repertoires than younger males. This may be either because individual males improve their performance as they get older (longitudinal increase) or because poor singers have reduced viability and, hence, are underrepresented in old age classes (cross-sectional increase). We studied the age dependence of repertoire size and other song traits in a German and a Swedish great reed warbler (Acrocephalus arundinaceus) population. We found marked differences between longitudinal and cross-sectional approaches, as well as between the two study populations. In the German population, we found that syllable switching, a measure of immediate versatility and strophe length, increased with age in a cross-sectional analysis. This was not because birds improved with age (longitudinally) but because syllable switching was positively correlated with male longevity. However, in Sweden, syllable switching seemed to be unrelated to age and longevity. In the Swedish population, individual males increased their repertoire size as they got older (longitudinal increase), but this did not happen in the German population. Hence, two populations, even when belonging to the same subspecies, may differ in whether or not they show delayed song maturation.
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| 44. |
- Friberg, Magne, et al.
(författare)
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Female mate choice determines reproductive isolation between sympatric butterflies
- 2008
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Ingår i: Behavioral Ecology and Sociobiology. - Berlin : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 62:6, s. 873-886
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Tidskriftsartikel (refereegranskat)abstract
- Animal courtship rituals are important for species recognition, and a variety of cues might be utilized to recognize conspecific mates. In this paper, we investigate different species-recognition mechanisms between two sympatric butterfly sister species: the wood white (Leptidea sinapis) and Real's wood white (Leptidea reali). We show that males of both species frequently court heterospecific females both under laboratory and field conditions. The long-lasting elaborate courtships impose energetic costs, since the second courtship of males that were introduced to two subsequent conspecific females lasted on average only one fourth as long as the first courtship. In this paper, we demonstrate that premating reproductive isolation is dependent on female unwillingness to accept heterospecific mates. We studied female and male courtship behavior, chemical signaling, and the morphology of the sexually dimorphic antennae, one of the few male traits visible for females during courtship. We found no differences in ultraviolet (UV) reflectance and only small differences in longer wavelengths and brightness, significant between-species differences, but strongly overlapping distributions of male L. sinapis and L. reali antennal morphology and chemical signals and minor differences in courtship behavior. The lack of clear-cut between-species differences further explains the lack of male species recognition, and the overall similarity might have caused the long-lasting elaborate courtships, if females need prolonged male courtships to distinguish between con- and heterospecific suitors.
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| 45. |
- Friesen, Christopher R., et al.
(författare)
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Correlated evolution of sexually selected traits: interspecific variation in ejaculates, sperm morphology, copulatory mate guarding, and body size in two sympatric species of garter snakes
- 2017
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Ingår i: Behavioral Ecology and Sociobiology. - : SPRINGER. - 0340-5443 .- 1432-0762. ; 71:12
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Tidskriftsartikel (refereegranskat)abstract
- Male reproductive success is dependent on a correlated suite of traits related to a species ecology and mating system dynamics. Closely related species differing in their mating systems and ecology, such as the garter snakes (Thamnophis), are ideal for studying the correlated evolution of sexually selected traits. Here, we compare the degree of sexual size dimorphism (SSD), copulatory behavior, copulatory plug size, and traits associated with sperm competition between two sympatric and closely related Thamnophis species, T. sirtalis and T. radix with divergent mating aggregation size and density. Our findings indicate that T. sirtalis has greater female-biased SSD, shorter copulations, and larger, more strongly adhering copulatory plugs than T. radix. Our finding that T. sirtalis have longer sperm and higher numbers of sperm per ejaculate is further evidence of more intense sperm competition in this species than in T. radix. However, this reduced number of sperm in the ejaculate means that T. radix males are likely capable of more matings per season than T. sirtalis. This result may reflect differences in feeding during the breeding season (obligate aphagy in T. sirtalis) and the potential for sperm loss in T. radix during prolonged copulations that are prevented in T. sirtlais by their substantial copulatory plugs. Our findings demonstrate that ecological and mating system dynamics have the capacity to strongly influence correlated selection of pre- and postcopulatory traits.
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| 46. |
- Friesen, C. R., et al.
(författare)
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Covariation in superoxide, sperm telomere length and sperm velocity in a polymorphic reptile
- 2020
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 74:6
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Tidskriftsartikel (refereegranskat)abstract
- Telomeres are DNA-protein caps at the ends of chromosomes that have been shown to be associated with male fertility may be heritable, reflect environmental influences and predict life span in some taxa. If heritable, paternal telomere length would be transmitted via sperm in the form of sperm telomere length (STL). We, therefore, investigated STL, sperm number and velocity in the Australian-painted dragon lizard, Ctenophorus pictus, an agamid lizard with distinct male colour morphs and related reproductive tactics. We measured telomere length in the sperm and blood as well as superoxide levels, as a measure for the potential for oxidative stress and ejaculate quality. We also noted a male's head colour (red, orange, yellow or blue) and whether or not they had a yellow gular bib. Previous research has reported that yellow males outcompete red males in sperm competition; we found that yellow males had significantly shorter STL than red males. Males with bibs had greater STL than did males without bibs. Superoxide levels measured in the blood were negatively correlated with STL. Whole blood TL and body length were weakly but positively correlated with STL. Superoxide measurements were negatively correlated with progressive sperm motility and straight line sperm velocity across all males. The ejaculates of males with bibs had lower sperm counts and velocity than males without bibs. Our research adds to the growing research that indicates the importance of considering both somatic and gametic telomeres when assessing the interaction between telomere dynamics, life history and reproductive strategies. Significance statement Telomeres are DNA-protein caps at the ends of chromosomes that reflect environmental stress may be heritable and epigenetically modified, may predict life span in some taxa and may influence the probability of paternity in sperm competition. Ours is one of the first studies to examine correlates of sperm telomere length in a non-mammalian, polymorphic species, but much more remains to be done. Telomere research in non-model species has focused on survival consequences of variation in telomere traits with less attention paid to the fact that sperm (and egg) telomere biology can link life history traits directly to reproductive physiology. We chose to investigate sperm velocity and sperm telomere length (STL) in the painted dragon lizard, Ctenophorus pictus, an agamid lizard with distinct male morphs and associated reproductive tactics. We also observed morph-specific differences in ejaculate quality and STL; in particular, males with yellow bibs had longer STL but poorer ejaculate quality metrics (e.g., number of sperm, velocity and proportion of progressively motile sperm) than males without the throat patch. The differences in STL between the morphs and the negative relationship between sperm velocity and STL, along with previous work on this species, suggest that telomere length and dynamics may be linked with the reproductive tactics of colour morphs within this species.
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| 47. |
- Fucini, S., et al.
(författare)
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Cuckoo wasps manipulate foraging and resting activities in their hosts
- 2014
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer-Verlag New York. - 0340-5443 .- 1432-0762. ; 68:11, s. 1753-1759
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Tidskriftsartikel (refereegranskat)abstract
- Parasite-induced alterations in host behaviour have been reported in a large number of taxa. However, some parasites are better than others to exploit the resources offered by their hosts. To date, our understanding of the extent to which some obligate parasites exploit social insect colonies is still limited. In this study, we examined parasite-mediated behavioural alterations of Polistes biglumis wasps parasitized by the obligate social parasite Polistes atrimandibularis by comparing host female-activity in parasitized and non-parasitized colonies. Host foundresses foraged more and rested less in parasitized than in non-parasitized colonies (controlling for the number of larvae in the nest, the time of day, and the day in the season). Next, we used short-term parasite removal experiments to investigate how social parasites manipulate their hosts. We found that parasitized hosts foraged more and rested less when social parasites were on the nest rather than after their removal, and we tested which kind of interactions occurred between parasites and hosts. P. atrimandibularis parasites may use mainly non-aggressive interactions (such as antennation and trophallaxis) to manipulate host activities, rather than visual, acoustic or chemical signals as other parasites do.
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| 48. |
- Garnham, Laura, et al.
(författare)
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The role of personality, cognition, and affective state in same-sex contests in the red junglefowl
- 2019
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Ingår i: Behavioral Ecology and Sociobiology. - : SPRINGER. - 0340-5443 .- 1432-0762. ; 73:11
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Tidskriftsartikel (refereegranskat)abstract
- Intra-species contests are common in the animal kingdom and can have fitness consequences. Most research on what predicts contest outcome focuses on morphology, although differences in personality and cognition may also be involved. Supporting this, more proactive individuals often have dominant status, although the causality of this relationship is rarely investigated. Contest initiators often win; thus, individuals that are more proactive in their personality (e.g., more aggressive, risk-taking) or cognition (e.g., more optimistic, impulsive) may initiate contests more often. To investigate this, we assayed the behavior and cognition of sexually mature male and female red junglefowl (Gallus gallus), a species in which both sexes contest over social status, before staging intra-sexual contests. We confirm that contest initiators were more likely to win. In males, individuals that behaved more boldly in a novel arena test were more likely to initiate and win contests. Female initiators tended to be less active in novel object test, more aggressive in a restrained opponent test, and respond less optimistically in a cognitive judgement bias test, whereas the main predictor of whether a female would win a contest was whether she initiated it. These results suggest that behaviors attributed to proactive and reactive personalities, and-at least for female red junglefowl-optimism, can affect contest initiation and outcome. Therefore, within species, and depending on sex, different aspects of behavior and cognition may independently affect contest initiation and outcome. The generality of these findings, and their fitness consequences, requires further investigation.
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| 49. |
- Gelter, Hans, et al.
(författare)
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High frequency of extra-pair parternity in Swedish Pied Flycatchers revealed by allozyme electrophoresis and DNA fingerprinting
- 1992
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 31:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- We used two genetic techniques to study multiple parentage in the pied flycatcher (Ficedula hypoleuca). Allozyme electrophoresis of 131 nestlings from 22 clutches sampled in 1982 and 1987 showed that one nestling had a mismatched allele compared with its putative parents. In one additional nest the devitation from Mendelian inheritance of parental genotypes suggested extra-pair paternity. The calculated probability of detecting multiple paternity from the genetic variation at four loci was 0.115. The estimated population frequency of extra-pair fertilization (EPF) was 13%, based on two mismatches and the probability of detecting multiple paternity. The seven families (n = 38 nestlings) in the 1987 sample were also analyzed by DNA fingerprinting using the M13 and Jeffrey's 33.15 probes. Overall, 24% (n = 9) of the nestlings analyzed were genetically inconsistent with their putative father, with EPF occurring in three (43%) of the seven clutches. One nestling originated by intraspecific brood parasitism. Comparison of the two techniques using the same samples showed that allozyme electrophoresis has a resolution only 11% of that of DNA fingerprinting, close to the calculated probability of detecting multiple paternity (0.115). Both techniques suggest that extra-pair fertilization is relatively common in the Swedish populations investigated compared to the low frequency reported from a Norwegian population
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| 50. |
- Goldenberg, Silvan U., et al.
(författare)
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Balancing the response to predation-the effects of shoal size, predation risk and habituation on behaviour of juvenile perch
- 2014
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 68:6, s. 989-998
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Tidskriftsartikel (refereegranskat)abstract
- Group size, predation risk and habituation are key drivers of behaviour and evolution in gregarious prey animals. However, the extent to which they interact in shaping behaviour is only partially understood. We analyzed their combined effects on boldness and vigilance behaviour in juvenile perch (Perca fluviatilis) by observing individuals in groups of one, two, three and five faced with four different levels of predation risk in a repeated measures design. The perch showed an asymptotic increase in boldness with increasing group size and the highest per capita vigilance in groups of two. With increasing predation risk, individuals reduced boldness and intensified vigilance. The interaction between group size and predation risk influenced vigilance but not boldness. In this context, individuals in groups of two elevated their vigilance compared to individuals in larger groups only when at higher risk of predation. Further, as only group size, they significantly reduced vigilance at the highest level of risk. With increasing habituation, solitary individuals became considerably bolder. Also, predation risk affected boldness only in the more habituated situation. Hence, repeated measures may be essential to correctly interpret certain relationships in behaviour. Our results suggest that perch may adjust boldness behaviour to group size and predation risk independently. This is rather unexpected since in theory, natural selection would strongly favour an interactive adjustment. Finally, vigilance might be particularly effective in groups of two due to the intense monitoring and detailed response to changing levels of risk.
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