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1.
  • Brodin, Anders, et al. (författare)
  • Memory and brain in food-storing birds: Space oddities or adaptive specializations?
  • 2008
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 114:7, s. 633-645
  • Forskningsöversikt (refereegranskat)abstract
    • Scatterhoarding birds that cache food items have become an important model system for the study of spatial memory and its correlates in the brain. In particular, it has been suggested that through adaptive specialization, species that cache food have better spatial memory and a relatively larger hippocampus than their non-caching relatives. Critics of this approach, dubbed neuroecology, maintain that neither of these hypotheses has been confirmed. Here, we review the evidence pertaining to a correlation between food-storing capability and the relative volume of the hippocampus. Hippocampal volume has been related to food-storing behaviour in comparisons between species, within species, or within individuals, but the evidence is not consistent. There are several possible reasons for this inconsistency, including: (1) food-hoarding birds may not always use memory for retrieval, (2) there may be systematic differences between data from North American and Eurasian species that affect the analysis, and (3) sample sizes have in many cases been too small. In addition, both the independent variable (degree of food-hoarding specialization) and the dependent variable (relative volume of the hippocampus) are not clearly and consistently defined. Alternatively, it is possible that the neuroecological hypothesis is false. Systematic empirical research is necessary to determine whether or not food-storing birds have evolved adaptive specializations in brain and cognition.
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2.
  • Bäckman, Johan, et al. (författare)
  • The influence of fat stores on magnetic orientation in day-migrating Chaffinch, Fringilla coelebs
  • 1997
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 103:3, s. 247-256
  • Tidskriftsartikel (refereegranskat)abstract
    • Earlier experimental studies have demonstrated the ability of day-migrating birds to perform migration under overcast skies, thereby indicating use of cues other than solar. The orientation behaviour of the chaffinch, a diurnal migrant, was investigated in orientation cage experiments during the autumn migration period. The aim of our experiments was to examine the relationship between different orientation cues and the influence of body condition on directional choices. We obtained the following results: 1. Chaffinches displayed a bimodal distribution of headings along a SW-NE axis when tested in the local geomagnetic field (controls); 2. When the geomagnetic field was experimentally deflected 90° counterclockwise, the chaffinches responded by changing their preferred axial orientation to SE-NW; and 3. The predictive power of stored fat reserves became evident when both the control and experimental samples were subdivided into fat and lean individuals. The majority of fat controls orientated towards a seasonally appropriate SW direction, whereas lean controls chose mean directions towards the NE. Experimentals followed the same pattern, but with the expected deflection, i.e. fat birds selected SE headings and lean individuals chose a NW mean direction.
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3.
  • Håkansson, P, et al. (författare)
  • Communal spawning in the common frog Rana temporaria - Egg temperature and predation consequences
  • 2004
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 110:9, s. 665-680
  • Tidskriftsartikel (refereegranskat)abstract
    • Females of the common frog, Rana temporaria, spawn synchronously at communal breeding sites, forming a communal egg mass of individual spawn clumps. A total of four spawning sites were studied. In the centre of the communal egg mass, daily maximum temperature was higher and minimum temperature lower than further out. Spawn clumps in the centre of the communal egg mass developed faster than single spawn clumps. In the centre of the egg masses, some spawn clumps suffered almost total egg mortality. This was probably the consequence of a cold spell with sub-zero temperatures in combination with a tendency for low minimum temperatures in the centre. In a laboratory study, worm leeches, Erpobdella spp., fed readily on eggs of common frog, while horse leeches, Haemopis sanguisuga, hardly ate any eggs. At the spawning sites, most worm leeches were found in single spawn clumps, far from the communal egg mass. Females which spawned late, when most of the spawning was over, preferred to spawn in the centre of the communal egg mass. This suggests that there is a net advantage for eggs in spawn clumps laid in the centre.
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4.
  • Nilsson, Anders, et al. (författare)
  • Environmental Conditions and Intraspecific Interference: Unexpected Effects of Turbidity on Pike (Esox lucius) Foraging
  • 2009
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 115:1, s. 33-38
  • Tidskriftsartikel (refereegranskat)abstract
    • Interference among predators decreases per capita foraging rates and has implications for both community dynamics and top-down trophic processes. Interference originates from behavioural interactions among foragers, and these behaviours could be affected by environmental conditions. In experiments on pike foraging alone or among conspecifics in different levels of water turbidity, we expected high turbidity to decrease the perceived risk of intraspecific interactions among pike, and thereby decrease the strength of interference, as turbidity would decrease the visual contact between individuals and act as a refuge from behavioural interactions. The results show that this is not the case, but suggest that interference is induced instead of reduced in high turbidity. Per capita foraging rates do not differ between pike foraging alone or in groups in our clear and moderately turbid treatments, indicating no effect of interference. As high turbidity enhances prey consumption for pike individuals foraging alone, but does not have this effect for pike in groups, high turbidity induces the relative interference effect. We suggest that future evaluations of the stabilizing effects of interference on community dynamics and its reduction of predation impact on top-down trophic cascades should consider potential unexpected effects of environmental conditions.
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5.
  • Nilsson, Jan-Åke (författare)
  • Establishment success of experimentally delayed juvenile marsh tits (Parus palustris)
  • 1990
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 85:1, s. 73-79
  • Tidskriftsartikel (refereegranskat)abstract
    • By experimentally manipulating the time when young marsh tits, Parus palustris, could become established, I tested the influence of size, hatching date, social dominance in caged situations, and time of season on establishment success. Individuals that managed to become established were divided into two groups: those that became established in new territories and those that were found in the same territory as the one where they were caught. In no circumstances did size, hatching date or social dominance influence establishment success. The only factor tested that had a significant effect on establishment success, was when the juveniles were released; those that established themselves in new territories had been released earlier than unsuccessful ones. Thus, prior occupancy rather than hatching date per se is the factor determining establishment in new territories. Juveniles that became re‐established in their former territory had been released significantly later than those not becoming re‐established. As the season progresses, increasingly fewer unestablished juveniles are present to fill vacancies. Thus, late‐released juveniles stood a better chance of finding their flock position still vacant compared with juveniles released early, whose previous positions would already have been occupied by other juveniles.
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6.
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7.
  • Andersson, Malte, 1941 (författare)
  • Evolution of classical polyandry: Three steps to female emancipation
  • 2005
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 111:1, s. 1-23
  • Tidskriftsartikel (refereegranskat)abstract
    • In classical polyandry, sex roles are reversed and a female reproduces with several males, each of whom raises his offspring with little or no help from her. This mating system occurs in some fishes and birds, and it is of great interest in relation to parental investment, sex role and sexual selection theory. The evolution of classical polyandry, however, is debated and not well understood. It is here suggested to generally take place in three main steps. (1) First evolves male care for eggs, for reasons that differ between fishes and birds. (2) Second, a female becomes able to lay more eggs than a male can accommodate. This can happen, for example, by evolution of male pregnancy or smaller body size, or by female production of more or larger eggs, made possible by larger female body size or more food. Polyandry in several taxa is associated with shift to a habitat rich in food during the breeding season, to novel specialised foraging methods, or to both. A favourable food situation may be crucial for evolution of classical polyandry. (3) In step three, females compete to lay two or more clutches in sequence for different males. Successful polyandrous females obtain more offspring, spreading traits that enhance success in competition over males. Step three may be most likely in species with small body size, for reasons of reproductive constraints and seasonality. Evolution of classical polyandry appears to have followed these steps in shorebirds, coucals and pipefishes, but the reasons why certain species differ from their close phylogenetic relatives in being polyandrous are far from clear. Behavioural and ecological studies of additional species, and detailed phylogenies of taxa with diverse mating systems including polyandry, are needed for testing these ideas.
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8.
  • Borg, Åsa A., et al. (författare)
  • Interactions Among Female Guppies (Poecilia reticulata) Affect Growth and Reproduction
  • 2012
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 118:8, s. 752-765
  • 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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9.
  • Griesser, Michael, et al. (författare)
  • Influence of Winter Ranging Behaviour on the Social Organization of a Cooperatively Breeding Bird Species, The Apostlebird
  • 2009
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 115:9, s. 888-896
  • Tidskriftsartikel (refereegranskat)abstract
    • Most cooperative breeding bird species live in family groups that are formed through the prolonged association of offspring with their parents. Research into cooperative families has in particular investigated the balance between cooperation and conflict over reproductive decisions. As a consequence of this research focus, social interactions among group members outside the breeding season are rarely studied, despite the fact that they are likely to be crucial for social decisions. We investigated the social dynamics and ranging behaviour of the family group living cooperatively breeding apostlebird (Struthidea cinerea) outside the breeding season. Group size changed between, but not within, the seasons, being smaller during the breeding season than in the winter season. This change in group size was a consequence of breeding groups merging after breeding, then splitting again before the next breeding season. While breeding groups used small, non-overlapping home ranges (x = 113 ha) around the nesting site, during winter groups moved up to 1200 ha (x = 598 ha), and interacted frequently with up to four other winter groups. In particular large groups often joined together during winter and spent up to 50% of their time associating with other large winter groups. This apparent fission-fusion system facilitated the exchange of group members, offering the possibility to form new breeding coalitions and new groups. The results of this study suggest that behaviour outside the breeding season can be of considerable importance to the social dynamics of both families and cooperative breeding in such systems.
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10.
  • Johnsson, Jörgen I, 1959, et al. (författare)
  • Social transfer of predation risk information reduces food location ability in European minnows (Phoxinus phoxinus).
  • 2007
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 113:2, s. 166-173
  • Tidskriftsartikel (refereegranskat)abstract
    • Little is known about how food location ability of animals is affected by social information of predation risk. This question was therefore addressed in an experimental study where naïve 'observer' European minnows (Phoxinus phoxinus) were allowed to search for food in a maze in the presence or absence of a predator (Salmo trutta). Observer minnows were accompanied by conspecific demonstrators which had previously been trained in the same maze either in the presence or absence of the predator. Observer minnows were most likely to locate food when the predator was absent both during their trial and during the pre-training of demonstrators. When demonstrators had been trained with predators, observer success in locating the food was halved, although they were never exposed to predation risk themselves. When observers were exposed to predation risk their probability of locating food was further reduced regardless of the experience of their demonstrators. Our results show that predation risk can affect the foraging ability of minnows both directly and indirectly through social information from conspecifics. We conclude that social information may influence and constrain individual behavioural decisions, especially in rapidly changing environments where private information is often insufficient.
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11.
  • Kemp, Darrell, et al. (författare)
  • Life history effects upon contest behaviour: Age as a predictor of territorial contest dynamics in two populations of the speckled wood butterfly, Pararge aegeria L.
  • 2006
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 112:5, s. 471-477
  • Tidskriftsartikel (refereegranskat)abstract
    • Although empirical studies of life history effects upon sexually selected phenomena have largely overlooked contest behaviour, recent research suggests that territorial contest participation in butterflies may be mediated by ageing per se. Verbal and mathematical arguments predict lifetime increases in the expression of risky male reproductive behaviours, such as fighting, under a range of ecological conditions. Here we explored the relevance of ageing per se to contest dynamics in two phenologically distinct populations of the speckled wood butterfly, Pararge aegeria. We established 160 experimental like-population contests among naive south Swedish and Madeiran dyads, 112 of which we varied the age difference between combatants by 3-4 d. Although this age asymmetry did not influence contest outcome in either population, we found weak positive covariance between the loser's age and contest duration amongst Madeiran males. This is consistent with a slight lifetime increase in aggression because the duration of these aerial persistence contests is a sensitive measure of the losing male's level of aggressive intent. However, the size of this effect (semi-partial correlation = 0.281) suggests age is not as strongly relevant to contest behaviour in P. aegeria as in other territorial butterflies. We discuss the ways in which ecological differences between butterfly species, particularly with respect to predation risk, may have influenced the evolution of lifetime aggressive strategies in this group.
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12.
  • Kullberg, Cecilia, et al. (författare)
  • An experimental study of predator recognition in great tit fledglings
  • 2002
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 108:5, s. 429-441
  • Tidskriftsartikel (refereegranskat)abstract
    • Studies of naturally predator-naïve adult birds (finches on predator-free islands) and birds experimentally hand reared in isolation from predators indicate that birds can recognise predators innately; that is, birds show anti-predator behaviour without former experience of predators. To reduce predation risk efficiently during the vulnerable fledgling period, we would predict an innate response to be fully developed when the chicks leave the nest. However, 30-day-old naïve great tit fledglings (Parus major) did not respond differently to a model of a perched predator than to a similarly sized model of a non-predator. Although chicks showed distress responses such as warning calls and freezing behaviour, they did not differentiate between the stimuli. In contrast, wild-caught first-year birds (4 mo old) and adults responded differentially to the two stimuli. Lack of recognition of a perched predator might be one explanation for the high mortality rate found in newly fledged great tits. Our results imply that parental care is not only important for food provisioning, but also to reduce predation risk during the time when fledglings are most vulnerable
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13.
  • Sundin, Josefin, et al. (författare)
  • Turbidity hampers mate choice in a pipefish
  • 2010
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 116:8, s. 713-721
  • 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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14.
  • Sundström, L. Fredrik, 1972, et al. (författare)
  • Dispersal potential is affected by growth-hormone transgenesis in coho salmon (Oncorhynchus kisutch).
  • 2007
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 113:4, s. 403-410
  • Tidskriftsartikel (refereegranskat)abstract
    • Potential ecological consequences on the natural environment of fast-growing transgenic fish with elevated intrinsic growth rates is an important question should such fish be allowed in commercial production systems. One trait that will strongly affect the spatial extent of consequences is the propensity of transgenic fish to disperse. We addressed this question in three experiments using different measures of spatial dispersal where we compared very young genotypically wild coho salmon with transgenic conspecifics in terms of: (i) group cohesion, (ii) exploratory behavior, and (iii) up- and downstream movements. Transgenic fish were more loosely aggregated, more likely to explore, and less likely to swim upstream, but equally likely to disperse downstream compared with genetically wild fish. These results show that dispersal behavior has been affected by transgenesis and that transgenic fish therefore may venture into habitats previously not used by wild fish. Given the importance of dispersal in ecological risk-assessment of transgenic fish, continued work within this area is warranted and experimental habitats should mimic the potential receiving natural habitats to which transgenic fish are likely to escape or be released to.
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15.
  • Sundström, L. Fredrik, 1972, et al. (författare)
  • Feeding on profitable and unprofitable prey: Comparing behaviour of growth-enhanced transgenic and normal coho salmon (Oncorhynchus kisutch)
  • 2004
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 110:5, s. 381-396
  • Tidskriftsartikel (refereegranskat)abstract
    • We compared the performance of normal and growth hormone-transgenic coho salmon feeding on surface drifting edible and inedible novel prey items in various social environments. With an inherently higher appetite, we predicted that transgenic fish would be more willing to feed on novel prey, and that visual company with another fish would enhance this difference further. Transgenic and normal fish, of similar size and age, were equally willing to attack both the edible (live insects) and inedible (artificial angling lure flies) prey, but transgenic fish did so faster and were more likely to make repeated attacks. Transgenic fish managed to seize and consume the edible prey after fewer attacks than did normal fish. However, swallowing of prey took longer than for normal fish. More transgenic individuals interacted with the inedible prey compared with normal salmon, and initially, transgenic fish in visual company with another fish also interacted more with the prey than single transgenic or any constellation of normal focal fish. With repeated exposures, the number of individuals attacking and the number of interactions with the prey decreased. These responses were stronger in transgenic fish, partly explained by the initially low response in normal fish. The observed differences are most likely the consequences of elevated levels of growth hormone in transgenic fish generating enhanced feeding motivation and reinforcement capacity. In a natural environment, the performance of a growth hormone-transgenic fish may therefore depend on the relative abundance of profitable vs. unprofitable prey, as well as the presence of other transgenic individuals.
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16.
  • Uller, Tobias, 1977, et al. (författare)
  • Direct exposure to corticosterone during embryonic development influences behaviour in an ovoviviparous lizard
  • 2006
  • Ingår i: ETHOLOGY. - : Wiley. - 0179-1613 .- 1439-0310. ; 112:4, s. 390-397
  • Tidskriftsartikel (refereegranskat)abstract
    • It is becoming increasingly clear that conditions experienced during embryonic development can be of major importance for traits subsequent to parturition or hatching. For example, in mammals, offspring from stressed mothers show a variety of changes in behavioural, morphological, and life-history traits. The effects of maternal stress on trait development are believed to be mediated via transfer of glucocorticoids, the main hormones released during the stress response, from mother to offspring. However, also other physiological maternal responses during stress could be responsible for changes in offspring phenotype. We investigated the direct effects of corticosterone on offspring development, without other confounding factors related to increased maternal stress, by injection of corticosterone in eggs of the ovoviviparous lizard Lacerta vivipara. Corticosterone-manipulated offspring did not show impaired development, reduced body size or body condition at parturition. However, corticosterone-treated offspring showed altered anti-predator behaviour, as measured by the time required to emerge from shelter after a simulated predator attack. Differential steroid exposure during development, possibly mediated by maternal stress response, may explain some of the variation in behaviour among individuals in natural populations.
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17.
  • Vilhunen, Sampsa, et al. (författare)
  • The bold and the variable : Fish with high heterozygosity act recklessly in the vicinity of predators
  • 2008
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 114:1, s. 7-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Variation in the innate behavioral response to predation threat is often assumed to reflect genetic differences among the prey individuals. To date, no published results, however, exist that would offer explanation for the origin of this behavioral variation within populations. Using microsatellites as markers, we estimated the genetic variability of juvenile brown trout (Salmo trutta) individuals whose behavior had been individually recorded in a trade-off situation where both predator chemical cues and food were present. Mean overall heterozygosity and the internal relatedness of fish associated significantly with their activity and foraging, so that the genetically more variable individuals showed more risk-prone behavior under predation risk. No association between genetic variability and behavior was found in trials where predator odors were not present. These results were consistent over the three study populations of brown trout with different backgrounds, suggesting that the phenomenon is of general nature in this species. Of the possible mechanisms suggested to enable the existence of the positive association between neutral microsatellite variation and fitness-related trait, the local effect hypothesis gained more support from our data than the general effect hypothesis.
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18.
  • Waldeck, Peter, 1963, et al. (författare)
  • Brood parasitism and nest takeover in common eiders
  • 2006
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 112:6, s. 616-624
  • Tidskriftsartikel (refereegranskat)abstract
    • Conspecific brood parasitism (CBP) is an alternative breeding tactic that occurs in many brood-tending animals and can have important fitness effects for both host and parasite. We use protein fingerprinting of egg albumen to distinguish the eggs from different females and to estimate the frequency, pattern and tactics of CBP and other forms of mixed maternity in a Hudson Bay population of common eiders (Somateria mollissima sedentaria). Mixed clutches, containing eggs from more than one female, occurred in 31% of the 86 nests studied that progressed to clutch completion. Other females than the host laid 8% of the eggs. In 11 (41%) of the mixed clutches another female laid before the host started laying, corroborating the hypothesis that takeover of nests started by other females accounts for many of the mixed clutches in this population. Our results also indicate that traditional non-molecular methods of identifying foreign eggs may considerably underestimate the frequency of mixed clutches.
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19.
  • Alström, Per (författare)
  • Is the Soft Song of the Brownish-Flanked Bush Warbler an Aggressive Signal?
  • 2013
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 119, s. 653-661
  • 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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20.
  • Amcoff, Mirjam, et al. (författare)
  • Male Courtship Pheromones Affect Female Behaviour in the Swordtail Characin ( Corynopoma riisei)
  • 2014
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 120:5, s. 463-470
  • 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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21.
  • Benson, Scott A., et al. (författare)
  • Graded-risk sensitivity in northern European mixed-species flocks of tit and nuthatch species
  • 2022
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 128:5, s. 437-442
  • Tidskriftsartikel (refereegranskat)abstract
    • Avian species often use anti-predator calls such that the costs and benefits of vigilance are distributed within the group. Some species respond differentially to graded risk by attending to relevant predator cues, such as head orientation and gaze direction. One benefit of graded-risk sensitivity is fewer missed foraging opportunities. It is not known how the makeup of risk response behaviors in mixed-species flocks may relate to the relative nuclearity of each species in the flock. In the current study, predator models were presented to two nuclear and two satellite species of passerines that frequently occur in natural mixed flocks. Predator models either faced toward or away from a nearby stocked feeder to simulate high and low risk of predation, and calling and seed-taking rates of the present flock were recorded. The nuclear species, great tits (Parus major) and crested tits (Lophophanes cristatus), took more seeds when the predator faced away from the feeder than toward it. The satellite species, Eurasian nuthatches (Sitta europaea) and willow tits (Poecile montanus), did not show an effect of predator orientation. No species showed consistent differences in calling behavior relative to predator orientation, although insufficient calling data for great tits prevented analysis for this species. The results of this study suggest that one aspect of nuclearity in mixed-species flocks is a tendency for graded-risk sensitivity, or alternatively, that satellite species are more sensitive to mere predator presence rather than to predator orientation cues.
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22.
  • Berdal Anderson, Monica, et al. (författare)
  • Innovation as part of a wider behavioural syndrome in the guppy: : Theeffect of sex and body size
  • 2018
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310.
  • 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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23.
  • Bobrowicz, Katarzyna, et al. (författare)
  • Social context hinders humans but not ravens in a short-term memory task
  • 2020
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 126:2, s. 125-139
  • Tidskriftsartikel (refereegranskat)abstract
    • Using resources shared within a social group – either in a cooperative or a competitive way - requires keeping track of own and others’ actions, which, in turn, requires well-developed short-term memory. Although short-term memory has been tested in social mammal species, little is known about this capacity in highly social birds, such as ravens. We compared ravens (Corvus corax) with humans in spatial tasks based on caching, which required short-term memory of one’s own and of others’ actions. Human short-term memory has been most extensively tested of all social mammal species, hence providing an informative benchmark for the ravens. A recent study on another corvid species (Corvus corone) suggests their capacity to be similar to the humans’, but short-term memory skills have, to date, not been compared in a social setting. We used spatial set-ups based on caches of foods or objects, divided into individual and social conditions with two different spatial arrangements of caches (in a row or a 3x3 matrix). In each trial, a set of three up to nine caches was presented to an individual that was thereafter allowed to retrieve all items. Humans performed better on average across trials, but their performance dropped, when they had to keep track of partner’s actions. This differed in ravens, as keeping track of such actions did not impair their performance. However, both humans and ravens demonstrated more memory-related mistakes in the social than in the individual conditions. Therefore, whereas both the ravens’ and the humans’ memory suffered in the social conditions, the ravens seemed to deal better with the demands of these conditions. The social conditions had a competitive element, and one might speculate that ravens’ memory strategies are more attuned to such situations, in particular in caching contexts, than is the case for humans.
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24.
  • Brodin, Tomas (författare)
  • Predator hunting modes and predator-prey space games
  • 2020
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 126, s. 476-485
  • Tidskriftsartikel (refereegranskat)abstract
    • Predators and prey are often engaged in a game where their expected fitnesses are affected by their relative spatial distributions. Game models generally predict that when predators and prey move at similar temporal and spatial scales that predators should distribute themselves to match the distribution of the prey's resources and that prey should be relatively uniformly distributed. These predictions should better apply to sit-and-pursue and sit-and-wait predators, who must anticipate the spatial distributions of their prey, than active predators that search for their prey. We test this with an experiment observing the spatial distributions and estimating the causes of movements between patches for Pacific tree frog tadpoles (Pseudacris regilla), a sit-and-pursue dragonfly larvae predator (Rhionaeschna multicolor), and an active salamander larval predator (Ambystoma tigrinum mavortium) when a single species was in the arena and when the prey was with one of the predators. We find that the sit-and-pursue predator favors patches with more of the prey's algae resources when the prey is not in the experimental arena and that the prey, when in the arena with this predator, do not favor patches with more resources. We also find that the active predator does not favor patches with more algae and that prey, when with an active predator, continue to favor these higher resource patches. These results suggest that the hunting modes of predators impact their spatial distributions and the spatial distributions of their prey, which has potential to have cascading effects on lower trophic levels.
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25.
  • Carlsen, Astrid (författare)
  • Prey predictability and preparation versus recovery breathing strategies in European shags Gulosus aristotelis (L.) diving in different habitats
  • 2023
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 129, s. 301-311
  • Tidskriftsartikel (refereegranskat)abstract
    • A recent study on the diving behaviour of European shags (Gulosus aristotelis (L.)) foraging in kelp forests off rocky coasts of Norway suggests surface durations are related only to the duration of the preceding dive, and hence are being used for respiratory recovery. These results contrast with earlier reports concerning shags foraging in highly tidal estuarine waters off the coast of Lundy Island, SW England, where there was a stronger relationship between dive durations and preceding pre-dive surface durations, suggesting the use of preparatory variation in oxygen loading. These two datasets were collected using different methods, and statistically analysed in quite different ways, so the contrasting results here could be due to different methodologies rather than the ecological differences between the two foraging environments. Here, we re-analyse the two datasets using similar statistical methods, and we confirm the contrasting results produced by the two datasets. We, therefore, conclude that shag breathing strategies do differ between these two marine environments, presumably reflecting adaptive facultatively plastic responses to differences in predictability of foraging dive durations. Off the Norwegian coast, unpredictable variation in the depth and availability of pelagic prey in complex environments may require more responsive post-dive respiratory recovery on the surface after each dive. In the more uniform English near-shore environment, however, pre-dive preparatory oxygen loading customised to match predictable dive-to-dive variation in benthic prey depths and foraging durations, may be more time and energy efficient.
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26.
  • Carlsen, Astrid (författare)
  • Temporal non-independence of foraging dive and surface duration sequences in the European shag Gulosus aristotelis
  • 2023
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 129, s. 254-268
  • Tidskriftsartikel (refereegranskat)abstract
    • Studies of foraging behaviour and respiratory physiology in breath-holding divers often assume that each dive cycle (dive plus surface duration) is physiologically and ecologically independent within a series (or "bout ") of sequential dives. We tested this assumption using time depth recorders and GPS data for more than 42,000 dives in 1289 bouts by 39 pairs of male and female European shags (Gulosus aristotelis) provisioning nestlings. We found distinct patterns of temporal autocorrelation over several dives within bouts, but this was driven mainly by consecutive dives of the same type, that is, runs of V-shaped (presumably prey searching) versus U-shaped (presumably active hunting) dives. We found no evidence of cumulative physiological effects (i.e. fatigue and/or lowered body temperature) across dives within a bout. However, within-individual variation in dive behaviour revealed complex interactions. Longer bouts were associated with more V-shaped dives, including more and longer runs of V-shaped dives. Meanwhile, more U-shaped dives and longer runs of U-shaped dives acted as limiting factors to bout lengths, with longer bouts being associated with more U-shaped dives only later in the bout. Interactions between bout length and body mass, and between dive order within the bout and body mass, also suggested various size-specific patterns in the temporal distribution of U-shaped dives. Long bouts and bouts ending in longer runs of V-shaped dives were more likely to indicate the termination of foraging activity. However, neither dive type nor bout length predicted whether individuals subsequently (i) stayed to forage in the same location or (ii) moved to a new location to continue foraging within the same trip from the nest. European shags therefore showed temporal non-independence across successive dive cycles and successive bouts of dives, likely as a result of temporal and spatial variation in prey availabilities rather than cumulative physiological effects that might contravene the assumptions in models of optimal dive behaviour.
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27.
  • Clements, J. C., et al. (författare)
  • "Urchin pinning": Behavioural observations reveal how hungry urchins actively prey upon their sea star predators
  • 2021
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 127:6, s. 484-489
  • Tidskriftsartikel (refereegranskat)abstract
    • Green sea urchins (Strongylocentrotus droebachiensis) are dominant components of benthic ecosystems that form aggregations and can transform entire kelp forests into barren systems. While these urchins are known to unwittingly consume practically anything in their path while grazing, detailed descriptions of active predatory behaviour on known predators (i.e., predator-prey reversal) are undocumented. Here, we use laboratory observations to describe the behavioural tactics used by starved S. droebachiesis to actively attack and consume sea stars, Crossaster papposus-a known predator of S. droebachiensis. We observed urchins preying on three separate sea stars, with one being substantially consumed by urchins within 24 hr. Urchins exhibited a direct mode of attack on sea stars by individually mounting and consuming the tips of the arms. Interestingly, we did not observe any conflict between individual urchins for attacking the sea star despite there being approximate to 80 starving urchins in the tank (and only 10-12 arms on the sea stars). Some sea stars did not attempt to escape urchin predation at all, while others attempted to escape by fleeing and lifting arms on top of the urchins. Given that sensory perception in sea stars is largely derived from the arm tips, we suggest that urchins directly attack and consume many sea star arm tips in an attempt to "pin" sea stars before consuming them. As such, we term this predatory behaviour "urchin pinning." These observations ultimately provide the first detailed behavioural documentation of how urchins actively prey on a known predator and provide a basis for a wealth of future research.
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28.
  • De Facci, Monica, et al. (författare)
  • Evidence for caste differences in anal droplet alarm pheromone production and responses in the eusocial thrips Kladothrips intermedius
  • 2013
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 119:12, s. 1118-1125
  • 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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29.
  • Griffith, Simon C., et al. (författare)
  • Variation in reproductive success across captive populations: Methodological differences, potential biases and opportunities
  • 2017
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 123:1, s. 1-29
  • 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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30.
  • Haemig, Paul D., et al. (författare)
  • Dynamic table-visiting behavior of birds at outdoor restaurants and cafes
  • 2021
  • Ingår i: Ethology. - : John Wiley & Sons. - 0179-1613 .- 1439-0310. ; 127:7, s. 505-516
  • Tidskriftsartikel (refereegranskat)abstract
    • Fear of humans and its effect on animal behavior is increasingly being recognized as an important structuring force in ecological landscapes, with consequences for ecological interactions and communities. When aggressive, physically dominant species are displaced by anthropogenic disturbance, physically weaker species exploit competitor and predator downtimes to forage in previously risky places. Birds feeding at outdoor restaurants and cafes in association with humans are exposed to fluctuating levels of perceived danger caused by frequently changing densities of human diners. Consequently, birds must make decisions about which dining tables to visit based on trade-offs between foraging gain and perceived danger from avian competitors and humans. We tested the hypothesis that interspecific differences in response to perceived danger, combined with varying densities of human diners, dynamically alter which bird species predominates at dining tables. We found that house sparrows (Passer domesticus) tolerated higher human diner-densities than larger-sized, more physically dominant Eurasian jackdaws (Coloeus monedula). Sparrows were usually the first birds to visit diner-occupied tables and spent more time there than jackdaws. However, at diner-abandoned tables, this pattern changed: During low diner-densities at surrounding tables, jackdaws were usually the predominant species in first visits and minutes spent visiting, while at high diner-densities sparrows usually predominated. Moreover, along a gradient of increasing human diner-density, sparrows gradually replaced jackdaws as the predominant species in first visits and time at abandoned tables. However, at diner-occupied tables, once a sparrow chose which table to visit, factors other than diner-density influenced its choice of where to forage there (table-top or ground). To our knowledge, our research is the first scientific study of table-visiting behavior by birds at outdoor restaurants and cafes, and the first to reveal interspecific differences in table-visiting behavior by birds there.
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31.
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32.
  • Jacobs, Ivo, et al. (författare)
  • Tool use and tooling in ravens (Corvus corax) : A review and novel observations
  • 2022
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613.
  • Tidskriftsartikel (refereegranskat)abstract
    • Corvids are known for their cognitive flexibility, and many have innovated various forms of tool use. Here, we review tool use and tooling in common ravens (Corvus corax) and describe additional observations. In total, they have used tools in 10 submodes and 11 modes. Of these modes, four were observed in captivity only, four in the wild only and three in both contexts. Five of these modes constitute tooling. When they manufactured tools, it was through detachment or subtraction. The purpose of most tool use was apparent, except when they used containers to transport small amounts of food that could be held in their bill and antelingual pouch (estimated to hold at least 16.2 ml). The small number of tool-using individuals per mode and the lack of detailed descriptions limit further interpretation and generalizability. Nonetheless, ravens are likely customary tool users in three modes and show the capacity for diverse tool use, which should be examined in dedicated future experiments.
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33.
  • Johnsson, Robin D., et al. (författare)
  • Wild-caught great tits Parus major fail to use tools in a laboratory experiment, despite facilitation
  • 2019
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 125:5, s. 324-331
  • 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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34.
  • Kim, Diana, et al. (författare)
  • Mating Preferences of the Gynogenetic Amazon Molly Differ Between Populations Sympatric with Different Host Species
  • 2014
  • Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 120:11, s. 1053-1061
  • 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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35.
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36.
  • Näslund, Joacim, 1985 (författare)
  • Unreplicable state-dependent effects on start-box emergence latency in wild-origin sticklebacks
  • 2021
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 127:8, s. 621-631
  • Tidskriftsartikel (refereegranskat)abstract
    • Animals are predicted to adjust their behaviour in relation to their bodily energetic state. Adjustment can be driven by either positive feedbacks (e.g. increased risk-taking with higher energetic status; "state-dependent safety") or negative feedbacks (e.g. reduced risk-taking with higher status; "asset protection"). This study investigated effects of food restriction and subsequent refeeding on boldness-like behaviour in three-spined sticklebacks (Gasterosteus aculeatus) and nine-spined sticklebacks (Pungitius pungitius). The same experimental design was run in 2 consecutive years, using a start-box emergence test to score behaviour, aiming for an exact replication in the second year. Results indicate that the results from the original and the replicated experiment did not match. Both years there was support for treatment effects, but the effects were qualitatively and quantitatively different. In 2012, the fish on a continuous high ration had longer emergence times than restricted-refed fish (suggesting asset protection as the feedback mechanism), while in 2013, this pattern is reversed (suggesting state-dependent safety as the feedback mechanism). In 2013, the general emergence time was also generally shorter than in 2012. These effects suggest that the methodology used may not be particularly robust. Subject fish were wild-caught, and differences in the populations across years, or in the individuals' prior experience, may have influenced the results. Alternatively, the start-box emergence test could be sensitive to minor (unperceived) alterations in procedures. Regardless, the present study suggests that the robustness of the start-box emergence test, which is a commonly used test (e.g. to score "boldness" in animal personality experiments) needs further investigation. In addition to the behavioural experiment, fish going through the refeeding protocol were shown to have higher body water content than fish on a continuously high food ration in both species. Food restriction also decreased relative liver mass in the short term, but it was restored during refeeding.
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37.
  • Périquet, Stéphanie, et al. (författare)
  • Effects of lions on behaviour and endocrine stress in plains zebras
  • 2017
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 123:9, s. 667-674
  • 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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38.
  • Siegmann, Susanne, et al. (författare)
  • Naked mole-rats (Heterocephalus glaber) do not specialise in cooperative tasks
  • 2021
  • Ingår i: Ethology. - : John Wiley & Sons. - 0179-1613 .- 1439-0310. ; 127:10, s. 850-864
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been proposed that naked mole-rat (Heterocephalus glaber) societies resemble those of eusocial insects by showing a division of labour among non-breeding individuals. Earlier studies suggested that non-breeders belong to distinct castes that specialise permanently or temporarily in specific cooperative tasks. In contrast, recent research on naked mole-rats has shown that behavioural phenotypes are continuously distributed across non-breeders and that mole-rats exhibit considerable behavioural plasticity suggesting that individuals may not specialise permanently in work tasks. However, it is currently unclear whether individuals specialise temporarily and whether there is a sex bias in cooperative behaviour among non-breeders. Here, we show that non-breeding individuals vary in overall cooperative investment, but do not specialise in specific work tasks. Within individuals, investment into specific cooperative tasks such as nest building, food carrying and burrowing is positively correlated, and there is no evidence that individuals show trade-offs between these cooperative behaviours. Non-breeding males and females do not differ in their investment in cooperative behaviours and show broadly similar age and body mass related differences in cooperative behaviours. Our results suggest that non-breeding naked mole-rats vary in their overall contribution to cooperative behaviours and that some of this variation may be explained by differences in age and body mass. Our data provide no evidence for temporary specialisation, as found among some eusocial insects and suggest that the behavioural organisation of naked mole-rats resembles that of other cooperatively breeding vertebrates more than that of eusocial insect species.
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39.
  • Sundberg, Jan (författare)
  • Absence Of Mate Guarding In The Yellowhammer (Emberiza-Citrinella)
  • 1992
  • Ingår i: Ethology. - 0179-1613 .- 1439-0310. ; 92:3, s. 242-256
  • Tidskriftsartikel (refereegranskat)abstract
    • The mate guarding behaviour of male yellowhammer (Emberiza citrinella) was studied with special reference to the effects of age, body size (tarsus length) and coloration of males. Measurements of intra-pair distance do at the most provide evidence for relatively lax mate guarding. On the other hand, patterns of male song activity and inter-male aggression were more in agreement with the predictions of the mate guarding hypothesis. The reasons for the comparatively low mate guarding intensity in the yellowhammer may be that males do not need to guard their mates intensely. Age differences were found in song and aggressive activity, older males singing and fighting the most. Size had no effect on guarding behaviour. Coloration was correlated with inter-male aggressiveness and conflict initiation propensity. Less colourful males fought the most in the pre-fertile period of their mates, whereas colourful and old males fought the most during the fertile period. This suggests that coloration may be an indicator of individual fighting and guarding ability.
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40.
  • Sundin, Josefin, et al. (författare)
  • Algal Turbidity Hampers Ornament Perception, but Not Expression, in a Sex-Role-Reversed Pipefish
  • 2016
  • Ingår i: Ethology. - : John Wiley & Sons. - 0179-1613 .- 1439-0310. ; 122:3, s. 215-225
  • 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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41.
  • Sundin, Josefin, et al. (författare)
  • Altered oceanic pH impairs mating propensity in a pipefish
  • 2013
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 119:1, s. 86-93
  • 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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42.
  • Sundin, Josefin, 1981-, et al. (författare)
  • Males show their best side revisited : Effects of predation pressure on laterality in wild guppies
  • 2023
  • Ingår i: Ethology. - : Wiley-VCH Verlagsgesellschaft. - 0179-1613 .- 1439-0310. ; 129:8, s. 390-405
  • Tidskriftsartikel (refereegranskat)abstract
    • The ability to detect and avoid predators has been suggested as one of the main drivers for behavioral lateralization. This is supported by studies reporting that animals from high-predation environments are more lateralized than those from low-predation environments. Some studies, however, have shown no effect of predator regime on lateralization. Lateralized behavior can also be driven by phenotypic asymmetry, where the more attractive side of the body is preferentially displayed during male-female interaction and courtship. The importance of fluctuating asymmetry for mate choice has been highly debated for a number of reasons. Here, we revisited the concepts of predator-induced behavioral lateralization and phenotypic asymmetry using wild Trinidadian guppies Poecilia reticulata from three different stream systems. Using fish collected from both high- and low-predation environments, we quantified behavioral lateralization in terms of directional turning bias, measured right-left body color asymmetry, and investigated whether a male side-showing preference was present in male-female interaction trials. We found that guppies were, at best, moderately lateralized on average (across all populations), without any general effect of predator regime. There were some slight stream-dependent side biases in color asymmetry, but this did not translate into a side-showing preference in any of the populations in the interaction trials. Some significant observed effects align with previously published results, but these were dependent on stream-origin and were not repeated across different experiments, complicating interpretation. We conclude that when investigating the effects of predation regime in general, and such effects on behavioral lateralization or fluctuating asymmetry in particular, attention must be focused toward several factors such as experimental assay used and population origin, and broad generalizations from results stemming from experiments including only one population should be avoided.
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43.
  • Tan, Hung, et al. (författare)
  • No evidence that the widespread environmental contaminant caffeine alters energy balance or stress responses in fish
  • 2023
  • Ingår i: Ethology. - 0179-1613 .- 1439-0310. ; 129:12, s. 666-678
  • Tidskriftsartikel (refereegranskat)abstract
    • Anthropogenic sources of environmental pollution are ever-increasing as urban areas expand and more chemical compounds are used in daily life. The stimulant caffeine is one of the most consumed chemical compounds worldwide, and as a result, has been detected as an environmental contaminant in all types of major water sources on all continents. Exposure of wildlife to environmental pollutants can disrupt the energy balance of these organisms, as restoration of homeostasis is prioritised. In turn, energy allocated to other key biological processes such as growth or reproduction may be affected, consequently reducing the overall fitness of an individual. Therefore, we aimed to investigate if long-term exposure to environmentally relevant concentrations of caffeine had any energetic consequences on wildlife. Specifically, we exposed wild eastern mosquitofish (Gambusia holbrooki) to one of three nominal concentrations of caffeine (0, 100 and 10,000 ng/L) and assayed individuals for metabolic rate, general activity, antipredator and foraging behaviour and body size as measures of energy expenditure or energy intake. We found no differences in any measured traits between any of the given exposure treatments, indicating that exposure to caffeine at current environmental levels may not adversely affect the energy balance and fitness of vulnerable freshwater fish. 
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44.
  • Triki, Zegni, et al. (författare)
  • A proposal to enhance data quality and FAIRness
  • 2022
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 128:9, s. 647-651
  • Forskningsöversikt (refereegranskat)abstract
    • In recent years, we witnessed an increasing number of funding agencies, scientific journals and scientists agreeing that society and science benefit from open access to research data. Benefits derive mainly from increased access to knowledge for all and improved transparency and credibility in academia. However, despite the advances in open science and open data, three significant aspects still need considerable policing: data quality, the accompanying summaries with basic information of the data files (i.e. metadata) and computational codes used to generate the research outcomes. Only by having these three components together, we can achieve efficient data sharing and reuse, and hence higher transparency. Here, we present two complementary approaches that potentially can help with shared data quality: (i) data file(s) sharing should be guided step-by-step in public archives with mandatory metadata, and (ii) journals creating assistant data editor positions at editorial boards with a leading role in data quality and computational reproducibility. Forty-four editors-in-chief in the field of behaviour, ecology and evolution shared their opinion with us regarding these two approaches. Although most of the views were divided, the majority estimated that their current editorial board members do not have the necessary skills to assess the quality of shared data. Since data are the core of research studies, we should consider not only data presence but also quality as a requirement for publication. 
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45.
  • Undin, Malin, et al. (författare)
  • Predicting breeding systems to guide conservation strategies : A kiwi example
  • 2022
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 128:7, s. 538-549
  • Tidskriftsartikel (refereegranskat)abstract
    • The breeding system and mating strategy of a species are at the heart of its behavioral ecology and part of determining its population dynamics. Thus, understanding breeding and mating behavior, and its flexibility, is important for accurate population modeling and successful conservation management. Here, we combine previous work with species-specific data and phylogenetic context to shine the spotlight on the breeding system of North Island (NI) brown kiwi, Apteryx mantelli, in a conservation context. The NI brown kiwi is of wide interest as a ratite, which are known for their variable breeding biology both within and between species, and its dire need of conservation management. With the aid of data from a long-term study in a rare, high-density population, we conclude that, although NI brown kiwi have several features characteristic of monogamous bird species (substantial investment in offspring by both parents, long-life expectancy, and well-developed sense of olfaction), it has as many that are consistent with potential for polygamy (uneven quality and distribution of resources, long and asynchronous breeding season, super-precocial chicks, and non-monogamous relatives). Consequently, we suggest that (1) the breeding system of NI brown kiwi is more flexible than has been widely recognized, and (2) further study of NI brown kiwi mating behavior would greatly benefit its conservation planning. Specifically, the prevalence of polygamy will directly affect genetic admixture, maintaining of genetic diversity, and distribution of parentage-all crucial factors influencing translocation success and genetic rescue. We argue that the NI brown kiwi study system could contribute to the increased incorporation of behavioral aspects in conservation management, and we provide suggestions for informative studies that would facilitate this.
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46.
  • Wengström, Niklas, 1969, et al. (författare)
  • Do individual Activity Patterns of Brown Trout (Salmo trutta) alter the Exposure to Parasitic Freshwater Pearl Mussel (Margaritifera margaritifera) Larvae?
  • 2016
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 122:9, s. 769-778
  • 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.
  •  
47.
  • Wilson, Alexander D. M., et al. (författare)
  • The Personality Behind Cheating : Behavioural Types and the Feeding Ecology of Cleaner Fish
  • 2014
  • Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 120:9, s. 904-912
  • 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.
  •  
48.
  • Dencker, Magnus, et al. (författare)
  • Gender differences and determinants of aerobic fitness in children aged 8-11 years.
  • 2007
  • Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6327 .- 1439-6319. ; 99, s. 19-26
  • Tidskriftsartikel (refereegranskat)abstract
    • Previous studies of gender differences in maximum oxygen uptake have come to different conclusions. Limited data exists where the determinants of maximum oxygen uptake have been evaluated in a comprehensive manner. Thus, we examined 248 children (140 boys and 108 girls), aged 7.9-11.1 years. Body composition was determined by dual-energy X-ray absorptiometry, measured variables were total body fat (TBF) and lean body mass (LBM). Maximal oxygen uptake (VO2peak) was measured by indirect calorimetry during a maximal cycle exercise test. Daily physical activity was assessed by accelerometers and duration of vigorous activity per day (VPA) was calculated. Left ventricular inner diastolic diameter (LVDD) was measured by echocardiography. Lung function was evaluated with spirometric testing and whole body plethysmography. Boys had between 8 and 18% higher values than girls for VO2peak, dependent upon whether VO2peak was expressed in absolute values or scaled to body mass, LBM or if allometric scaling was used. In multiple regression analysis absolute values of aerobic fitness were independently related to LBM, maximal heart rate (Max HR), gender, LVDD, and VPA. Furthermore, when VO2peak was scaled to body mass it was independently related to In TBF, Max HR, gender, VPA, and LVDD. Lung function had no relation to VO2peak. Our study concludes that body composition is the main predictor for VO2peak, in children aged 8-11 years, whereas VPA or LVDD has only a modest impact. Existing gender differences in VO2peak cannot be explained only by differences in body composition, physical activity, or heart size.
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49.
  •  
50.
  • Drerup, Christian, et al. (författare)
  • Dynamic visual noise has limited influence on the habitat selection and behavioural activity of crustaceans and cephalopods
  • Ingår i: Ethology. - 0179-1613. ; 130:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Environments contain various forms of noise that can interfere with the ability of animal sensory systems to perceive information. One ubiquitous type of visual noise in shallow aquatic habitats is caustic flicker (or caustics), consisting of dynamically moving light patterns caused by the refraction of light when passing through the water's rippling surface. While some teleost fish avoid environments with caustic noise (where their prey can be more difficult to detect), it remains untested whether caustics affect the habitat selection of invertebrates. In the present study, we ask whether three invertebrate species, the shore crab Carcinus maenas, the brown shrimp Crangon crangon, and the common cuttlefish Sepia officinalis, prefer or avoid associating with environments with caustic noise, and whether caustics affect their behavioural activity and habitat exploration. To do this, we exposed the three species in binary choice experiments to different simulated caustic noise levels varying in their temporal (speed) and spatial (definition) components. Neither of the three tested invertebrate species spent more or less time in environments with higher caustic noise levels. While we also found no evidence that caustics affected the behavioural activity and exploration of Ca. maenas and S. officinalis, the brown shrimp Cr. crangon reduced its activity with increasing spatial caustic noise. However, all obtained effect sizes in this study were small, suggesting that caustic noise only minimally affects invertebrate behaviour. Overall, our results show that, unlike in teleost fish, caustics have limited influence on the habitat selection, exploration, and activity of crustaceans and cephalopods.
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