| 1. |
- Borg, Åsa A., et al.
(författare)
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Interactions Among Female Guppies (Poecilia reticulata) Affect Growth and Reproduction
- 2012
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 118:8, s. 752-765
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Tidskriftsartikel (refereegranskat)abstract
- Competition among females over resources may have consequences for their resource budgets and thereby the resource allocation between growth and reproduction. In addition, the consequences of femalefemale interactions may differ for dominant and subordinate individuals, with the dominant ones being at an advantage. In this study, we investigated the consequences of femalefemale competition in guppies by manipulating the competitive environment of females. We found that large guppy females dominated smaller females and that interactions between females likely are costly because females exposed to competition grew less. These females compensated by growing at a higher rate when no longer subjected to competition. The higher growth rate might in turn be the cause of the reduced reproductive effort in the more competitive treatments. Furthermore, interactions were more costly for females when they were in the subordinate role than in the dominant role, because the reduction in growth and reproductive effort was highest in females exposed to larger competitors. Whether there was a differential allocation of resources into growth and reproduction depending on dominance status needs further investigation. However, in general, smaller females had a higher growth rate than larger females, independent of competitive level. We also found a negative relationship between reproduction and growth in all treatments, indicating a cost of reproduction.
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| 2. |
- Sundin, Josefin, et al.
(författare)
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Turbidity hampers mate choice in a pipefish
- 2010
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 116:8, s. 713-721
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Tidskriftsartikel (refereegranskat)abstract
- European coastal waters have in recent years become more turbid as algal growth has increased, probably due to eutrophication, global warming and changes in fish communities. Turbidity reduces visibility, and such changes may in turn affect animal behaviour as well as evolutionary processes that are dependent on visual stimuli. In this study we experimentally manipulated water visibility and olfactory cues to investigate mate choice using the sex role-reversed broad-nosed pipefish Syngnathus typhle as our study organism. We show that males spent significantly longer time assessing females when they had access to full visual cues, compared to when visibility was reduced. Presence or absence of olfactory cues from females did not affect mate choice, suggesting that the possible use of smell could not make up for a reduction in visibility. This implies that mate choice is environmentally dependent and that an increased turbidity may affect processes of sexual selection through an impaired possibility for visually based mate choice.
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| 3. |
- Alström, Per
(författare)
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Is the Soft Song of the Brownish-Flanked Bush Warbler an Aggressive Signal?
- 2013
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 119, s. 653-661
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Tidskriftsartikel (refereegranskat)abstract
- Soft songs have been detected in many songbirds, but in most species, research on soft songs has lagged behind studies of broadcast songs. In this study, we describe the acoustic features of a soft song in the brownish-flanked bush warbler Cettia fortipes. Compared with the broadcast song, the warbler's soft song was characterized by a lower minimum frequency and longer duration, and it had a higher proportion of rapid frequency modulation notes. Using playback experiments, some in combination with mounted specimens, we found different responses to soft and broadcast songs, and we found that soft song can predict aggressive escalation (attack). We conclude that the soft song is an aggressive signal in this species.
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| 4. |
- Amcoff, Mirjam, et al.
(författare)
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Male Courtship Pheromones Affect Female Behaviour in the Swordtail Characin ( Corynopoma riisei)
- 2014
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 120:5, s. 463-470
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Tidskriftsartikel (refereegranskat)abstract
- Pheromones constitute an important cue used by both males and females during courtship. Here, we investigate the effect of male pheromones on female behaviour in the swordtail characin (Corynopoma riisei), a species of fish where males have a caudal pheromone gland which has been suggested to affect female behaviour during courtship. We subjected female C.riisei to male courtship pheromones and investigated the effect on both female behaviour and brain serotonergic activity levels compared to a control group. While no difference in serotonergic activity was found, the pheromone-treated females showed lower stress levels compared to the control group. Furthermore, pheromone-treated females increased locomotor activity over time, while a decrease in locomotor activity was observed in the control group. These results suggest that the male courtship pheromones may serve to reduce female stress and increase female activity, possibly to aid males in gaining access to females and facilitating sperm transfer.
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| 5. |
- Berdal Anderson, Monica, et al.
(författare)
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Innovation as part of a wider behavioural syndrome in the guppy: : Theeffect of sex and body size
- 2018
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310.
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Tidskriftsartikel (refereegranskat)abstract
- Recent work on animal personalities has shown that individuals within populations often differ consistently in various types of behaviour and that many of these behaviours correlate among individuals to form behavioural syndromes. Individuals of certain species have also been shown to differ in their rate of behavioural innovation in arriving at novel solutions to new and existing problems (e.g., mazes, novel foods). Here, we investigate whether behaviours traditionally studied in personality research are correlated with individual rates of innovation as part of a wider behavioural syndrome. Guppies (Poecilia reticulata) of both sexes from three different wild population sources were assessed: (a) exploration of an open area; (b) speed through a three‐dimensional maze; (c) investigation of a novel object; and (d) attraction to a novel food. The covariance structure (syndrome structure) was examined using structural equation modelling. The best model separated behaviours relating to activity in all contexts from rates of exploration/investigation and innovation. Innovative behaviour (utilizing new food and moving through a novel area) in these fish therefore forms part of the same syndrome as the traditional shy‐bold continuum (exploration of an open area and investigation of a novel object) found in many animal personality studies. There were no clear differences in innovation or syndrome structure between the sexes, or between the three different populations. However, body size was implicated as part of the behavioural syndrome structure, and because body size is highly correlated with age in guppies, this suggests that individual behavioural differences in personality/innovation in guppies may largely be driven by developmental state.
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| 6. |
- De Facci, Monica, et al.
(författare)
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Evidence for caste differences in anal droplet alarm pheromone production and responses in the eusocial thrips Kladothrips intermedius
- 2013
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Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 119:12, s. 1118-1125
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Tidskriftsartikel (refereegranskat)abstract
- Thrips (Thysanoptera) are tiny insects that produce anal secretions whenthreatened. Several studies have shown that, depending on the species,the droplets may contain alarm pheromones and/or repellents againstenemies. In the eusocial gall-inducing thrips Kladothrips intermedius bothlarvae and adults produce such droplets. There are two castes of adults inthis species, soldiers (the sub-fertile and gall-bound defenders) and dispersers(winged and capable of initiating a gall). We tested the proclivityof secreting anal droplets by the two castes and whether the anal dropletsinduce different behavioural responses in relation to the emitter–receiver’scaste in a contact chemoreception bioassay. Although secretionpatterns were similar between castes, exposure to anal droplets emitted bydifferent castes elicited different behavioural responses in adults in thebioassay. When exposed to soldiers’ anal droplets, dispersers significantlyreduced the distance moved while soldiers significantly increased thedistance moved, compared to when they were exposed to hexane control.In contrast, no differences in the distance moved were observed for anycaste when exposed to dispersers’ anal droplets versus hexane control.Increased activity in soldiers when exposed to their own anal droplets is apredicted response to enhance the overall defence of the gall when underthreat, whereas dispersers should slow down their activity when exposedto such ‘warning signal’. Thus, the behavioural data indicate that the analdroplets emitted by soldiers are likely to contain an alarm pheromone.
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| 7. |
- Griffith, Simon C., et al.
(författare)
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Variation in reproductive success across captive populations: Methodological differences, potential biases and opportunities
- 2017
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Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 123:1, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of ‘model’ species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory – the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life-history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency.
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| 8. |
- Johnsson, Robin D., et al.
(författare)
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Wild-caught great tits Parus major fail to use tools in a laboratory experiment, despite facilitation
- 2019
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 125:5, s. 324-331
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Tidskriftsartikel (refereegranskat)abstract
- Studies investigating tool use in animals that are not known tool users in the wild are important in helping to understand how and under what circumstances this ability might arise. Tool use appears to be uncommon in great tits (Parus major), with only a single documented observation in which a wild great tit used conifer needles to extract larvae from crevices in trees. In a laboratory-based experiment, we examined whether wild-caught great tits could learn to use tools in a similar manner. We presented the birds with two different tool use tasks in which they would need to use either a stick or a hook to extract an otherwise inaccessible meal worm from a transparent plastic tube. First, the birds passed a simpler training criterion (pulling a tool with an attached food reward) that aimed to reduce the difficulty of the task. Nevertheless, none of the individuals learnt to use tools in either of the two tasks. This result stands in stark contrast to the abilities of some corvids and parrots, which can learn to use tools in captivity, even though some of them are not tool users in the wild. We believe that tool use might be difficult for some birds to learn since the skills required for this ability seem not to be part of their natural foraging behaviour.
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| 9. |
- Kim, Diana, et al.
(författare)
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Mating Preferences of the Gynogenetic Amazon Molly Differ Between Populations Sympatric with Different Host Species
- 2014
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Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 120:11, s. 1053-1061
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Tidskriftsartikel (refereegranskat)abstract
- Gynogenetic species rely on sperm from heterospecifics for reproduction but do not receive genetic benefits from mating because none of the paternal genome is incorporated into offspring. The gynogenetic Amazon molly (Poecilia formosa) is a species of hybrid origins that are sympatric with one of the two parent species that provide sperm for reproduction, P. latipinna or P. mexicana. Amazons should not prefer to mate with one species over the other because sperm from both species will trigger embryogenesis, but mating preferences may be present in Amazons through other mechanisms. Amazons may prefer the more familiar species (males found in sympatry), or Amazons may prefer males with the greatest lateral projection area (LPA), a preference that is present in the parent species and may be retained within the Amazon hybrid genome. We tested association preferences of two populations of Amazons sympatric with either P. mexicana or P. latipinna. We first performed live trials to test whether Amazons preferred one host species over the other and found that neither population of Amazons showed a preference. We then tested whether Amazons preferred sympatric male (familiar) host or the male with the greatest lateral projection area (LPA) using four animated male models that varied in host species and manipulation of LPA. We found Amazons from a population sympatric with P. latipinna showed no variation in their association preference across the different models. In contrast, Amazons from a population sympatric with P. mexicana (naturally small LPA) spent more time associating with the male models that had smaller LPA, which is more familiar to this population of Amazons. We suggest that Amazons may have population differences in mating preferences, where Amazons sympatric with P. latipinna may not show mating preference for host species, but Amazons sympatric with P. mexicana may show preferences for more familiar-shaped males.
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| 10. |
- Périquet, Stéphanie, et al.
(författare)
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Effects of lions on behaviour and endocrine stress in plains zebras
- 2017
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 123:9, s. 667-674
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Tidskriftsartikel (refereegranskat)abstract
- Living under predation risk may alter both behaviour and physiology of potential prey. In extreme cases, such alterations may have serious demographic consequences, and recent studies support that non-lethal effects of predation may have broad ecological consequences. However, behavioural and physiological responses to predation risk may be related to trade-offs associated with resource acquisition and direct predation risk. We validated an enzyme-linked immunoassay (EIA) for non-invasive monitoring of stress in plains zebras (Equus quagga) from faecal material. We used this assay in combination with behavioural data to assess if plains zebras living with and without lions (Panthera leo) in a mountain savannah in southern Africa differed in behaviour and physiology, and if such differences were influenced by seasons with contrasting resource availability. Zebra group sizes did not differ between areas with and without lions, but zebra groups had more juveniles in an area with lions than groups in an area without lions, but only during the wet season. Similarly, we observed differences in individual vigilance, foraging behaviour and stress hormone concentrations, but all these differences were influenced by seasons. Despite these seasonal influences, our study did not suggest that zebras in an area with lions spent a higher proportion of time being vigilant, a lower proportion of time foraging, or had higher stress hormone levels. Our results instead suggest that zebras' responses to lion presence were highly context dependent and the result of complex interactions between resource abundance and cues about predation risk. Because of the obvious ecological and evolutionary ramifications of such findings, we argue that further research is needed to define the spatial and temporal scales over which predators impose indirect effects on their prey.
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| 11. |
- Sundin, Josefin, et al.
(författare)
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Algal Turbidity Hampers Ornament Perception, but Not Expression, in a Sex-Role-Reversed Pipefish
- 2016
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Ingår i: Ethology. - : John Wiley & Sons. - 0179-1613 .- 1439-0310. ; 122:3, s. 215-225
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Tidskriftsartikel (refereegranskat)abstract
- Sexual ornaments are used both in intra- and intersexual contexts, and these signals have evolved to function in the particular habitat the animal is adapted to. Habitat characteristics may, however, change rapidly due to anthropogenic effects, sometimes at rates too fast for many organisms to adaptively respond. In aquatic ecosystems, eutrophication is currently changing chemical as well as visual properties of the environment. Algae blooms increase water turbidity, and the reduction of water transparency thus has the potential to alter visual ornaments and their perception. However, results are not congruent. Rather, algae turbidity may decrease, increase, or leave ornaments unaffected. The effect seems to depend on exposure time, condition, population and species. Here, we found that the perception of sexual signals, but not their expression, was hampered by turbidity in the sex-role-reversed pipefish Nerophis ophidion. In a laboratory experiment we found that female sexual ornaments (i.e., blue color markings and a skinfold) and fecundity was unaffected by turbidity. Male adaptive mate choice for larger females with large ornament was, however, hampered under turbid conditions, whereas in clear water males choose larger, more ornamented females. Thus, we show that water turbidity had no effect on signal expression but did hamper ornament perception and consequently randomized mate choice.
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| 12. |
- Sundin, Josefin, et al.
(författare)
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Altered oceanic pH impairs mating propensity in a pipefish
- 2013
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 119:1, s. 86-93
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic disturbance is currently altering the environment of terrestrial as well as aquatic organisms. Those changes affect a variety of animal behaviours, which in turn may cause changes in species interactions, population dynamics and evolutionary processes. In marine ecosystems, nutrient enrichment may elevate pH, while it is reduced by carbon dioxide-induced ocean acidification. These two processes are not expected to balance one another but rather to affect the environment at different times and scales. We here show experimentally that an increase in water pH has a negative effect on mating propensity in the broad-nosed pipefish Syngnathus typhle, whereas lowered pH did not elicit the same detrimental effect. This study provides, to our knowledge, the first evidence that mating propensity is impaired by an increase in pH, suggesting that anthropogenic nutrient enrichment in aquatic ecosystems may change the processes of sexual selection and population dynamics solely on the basis of altered water pH.
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| 13. |
- Wengström, Niklas, 1969, et al.
(författare)
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Do individual Activity Patterns of Brown Trout (Salmo trutta) alter the Exposure to Parasitic Freshwater Pearl Mussel (Margaritifera margaritifera) Larvae?
- 2016
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 122:9, s. 769-778
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that interindividual differences in the activity of brown trout alter the exposure to parasitic freshwater pearl mussel glochidia was tested in a Swedish stream. Wild yearling brown trout (N=103) were caught, individually tagged for identification and scored for open-field activity during standardized laboratory tests in June. Fifty gravid freshwater pearl mussels were relocated to the stream, where after the trout were released back into the stream. The fish were recaptured in October (N=35), checked for glochidia encystment (infested individuals: n=6) and re-scored for open-field activity traits. Swimming velocity during the test was higher in fish infected with glochidia, suggesting that high activity could increase their exposure to glochidia. Potentially, as metabolism rate and ventilation rate typically increase with activity, elevated activity may lead to an increased likelihood of glochidia passing over the gills. This novel finding suggests that glochidia infestation is non-random and that the behaviour of the host fish can influence the likelihood of glochidia infestation.
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| 14. |
- Wilson, Alexander D. M., et al.
(författare)
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The Personality Behind Cheating : Behavioural Types and the Feeding Ecology of Cleaner Fish
- 2014
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 120:9, s. 904-912
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Tidskriftsartikel (refereegranskat)abstract
- The complex mutualistic relationship between the cleaner fish (Labroides dimidiatus) and their 'clients' in many reef systems throughout the world has been the subject of debate and research interest for decades. Game-theory models have long struggled with explaining how the mixed strategies of cheating and honesty might have evolved in such a system and while significant efforts have been made theoretically, demonstrating the nature of this relationship empirically remains an important research challenge. Using the experimental framework of behavioural syndromes, we sought to quantitatively assess the relationship between personality and the feeding ecology of cleaner fish to provide novel insights into the underlying mechanistic basis of cheating in cleaner-client interactions. First, we observed and filmed cleaner fish interactions with heterospecifics, movement patterns and general feeding ecology in the wild. We then captured and measured all focal individuals and tested them for individual consistency in measures of activity, exploration and risk taking (boldness) in the laboratory. Our results suggest a syndrome incorporating aspects of personality and foraging effort are central components of the behavioural ecology of L. dimidiatus on the Great Barrier Reef. We found that individuals that exhibited greater feeding effort tended to cheat proportionately less and move over smaller distances relative to bolder more active, exploratory individuals. Our study demonstrates for the first time that individual differences in personality might be mechanistically involved in explaining how the mixed strategies of cheating and honesty persist in cleaner fish mutualisms.
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| 15. |
- Näslund, Joacim, 1985, et al.
(författare)
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Design of Emergence Test Arenas Can Affect the Results of Boldness Assays
- 2015
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Ingår i: Ethology. - : Wiley. - 0179-1613. ; 121:6, s. 556-565
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigate whether and how arena design of emergence tests (a commonly used boldness assay where the latency to emerge from a start box is measured) can affect the behaviour of the subject animals. We used two populations of wild brown trout fry, captured on their hatching grounds, and measured emergence latency in arenas with two different sizes of start-box gates and two different environments into which the fish emerges from the start box (barren and complex), in a factorial design. We found that arena design affected the behaviour of the fish, but only in one of the populations. In the affected population, a large start-box gate in combination with a barren environment reduced emergence latency. Furthermore, the time from leaving the box until entering another compartment on the opposite side of the arena was shorter in a barren environment as compared to a more complex environment. We also found that smaller brown trout fry generally showed lower tendency for emerging from the start box at all. The results of this study suggest that direct comparisons among results from experiments using different arena designs may be problematic and highlight the importance of reporting details of arena design in publications. BOTT JC, 1989, BEHAVIOUR, V108, P104
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| 16. |
- Wallerius, Magnus L., et al.
(författare)
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Interspecific association of brown trout (Salmo trutta) with non-native brook trout (Salvelinus fontinalis) at the fry stage
- 2017
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Ingår i: Ethology. - : Wiley. - 0179-1613. ; 123:12, s. 933-941
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Tidskriftsartikel (refereegranskat)abstract
- The introduction of non-native brook trout (Salvelinus fontinalis) in Europe has led to displacement and decreasing populations of native brown trout (Salmo trutta). Some studies have found that brown trout shift to a diet niche similar to brook trout when the two species live in sympatry, which conflicts with the competitive exclusion principle. A change in feeding niche may be a sign of early interspecific association and social learning, leading to behavioral changes. As a first step to address this possibility, it is essential to assess the interspecific association between the species during the early ontogenetic life stages. In this study, we therefore assess whether juvenile brown trout associate with non-native juvenile brook trout to the same extent as with conspecifics by setting up two experiments: (i) a binomial choice test allowing visual and chemical cues to estimate the species specificity of group preference, and (ii) an association test without physical barriers to estimate the degree of association of a focal brown trout with a group of either conspecifics or heterospecifics. In experiment (1), we found that focal juvenile brown trout preferred to associate with the stimuli groups and did not discriminate either against conspecific or heterospecific groups. Furthermore, more active individuals showed stronger preference for the stimuli group than less active ones, regardless of species. In experiment (2), we found that brook trout groups had a tighter group structure than brown trout groups, and that focal brown trout showed stronger association with brook trout than with brown trout. These results indicate that brown trout may associate with brook trout at an early life stage, which would allow for interspecific social learning to occur. Future studies should look closer into causes and consequences of interspecific association and social learning, including potential effects on the phenotype selection in brown trout populations.
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| 17. |
- Zavorka, Libor, et al.
(författare)
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Effects of familiarity and population density on competitive interactions and growth: an experimental study on a territorial salmonid fish
- 2015
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Ingår i: Ethology. - : Wiley. - 0179-1613. ; 121:12, s. 1202-2211
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Tidskriftsartikel (refereegranskat)abstract
- The deleterious effect of competition for space and food in animals increases with increasing population density. In contrast, familiarity towards conspecifics can relax the intensity of interference competition. Here, we hypothesized that familiarity towards conspecifics mitigates the effect of density-dependent growth and dispersal behaviour in territorial animals. To test this, wild-captured juvenile brown trout were subjected to two consecutive laboratory experiments. First, growth and fin erosion were measured for 40 d in a 2 × 2 factorial design manipulating density and familiarity. The density was manipulated via size of experimental tanks, while per capita food abundance and fish number was constant. All fish were subsequently exposed to an emergence test, giving them the option to leave their group and disperse to a novel unoccupied environment. The results show that familiarity increases growth and decreases the level of fin erosion (i.e. proxy of intensity of aggressive interactions). We found no significant effect of population density on growth rate. However, there was a tendency towards higher fin erosion in fish kept under high density. The growth of individuals was also affected by their size rank within the group, with the largest individuals in each group growing disproportionally faster than the rest of the group, probably due to their high social rank. However, the second and third fish in the size rank did not grow significantly faster and tended to suffer higher mortality than the rest of the group. During the emergence test, the largest individuals in the familiar groups left the shelter either as the first (six of 12 groups) or last (five of 12 groups) individual in the group, while no such pattern was observed in unfamiliar groups. Our results suggest that individuals in familiar groups receive less aggression and stress (i.e. fin damage) and grow faster than fish in unfamiliar groups. The mechanisms indicated in this laboratory study may be especially important in highly fecund organisms like fish which undergo density-dependent bottlenecks during early life.
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