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  • 1.
    Almbro, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Department of Ethology. Stockholm University.
    The downfall of mating: the effect of mate-carrying and flight muscle ratio on the escape ability of a pierid butterfly2009In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, no 3, p. 413-420Article in journal (Refereed)
  • 2.
    Amcoff, Mirjam
    et al.
    Uppsala universitet, Institutionen för ekologi och evolution.
    Arnqvist, Göran
    Uppsala universitet, Institutionen för ekologi och evolution.
    Kolm, Niclas
    Uppsala universitet, Institutionen för ekologi och evolution.
    Courtship signalling with a labile bilateral signal: males show their best side2009In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, no 12, p. 1717-1725Article in journal (Refereed)
    Abstract [en]

    Asymmetries in courtship signals can result from both developmental instability during ontogeny and from temporary or permanent damage following mating, fighting, or interactions with predators. These two types of asymmetries, which can be divided into fluctuating asymmetry (FA) and damage asymmetry (DA), have both been suggested to play an important role in mate choice as potential honest indicators of phenotypic and/or genetic quality, while at the same time, DA may affect ornament asymmetry in a random manner. Interestingly, despite the massive research effort that has been devoted to the study of asymmetry during the past decades, very little is known about how an individual's behaviour relates to asymmetry. Here, we measure and characterise asymmetry in morphological courtship signals in Corynopoma riisei, a fish where males carry elaborate paddle-like appendices on each side of the body that they display in front of females during courtship. Moreover, we investigate whether male courtship display, employing this bilateral morphological trait, reflects trait asymmetry. Finally, we assess whether males respond to phenotypic manipulations of DA with corresponding changes in courtship behaviour. We show that male display behaviour is asymmetric in a manner that reflects asymmetry of their morphological courtship trait and that male display behaviour responds to manipulations of asymmetry of these paddles. Our results thus suggest that males preferentially use their best side and, hence, that males respond adaptively to temporary changes in signal trait asymmetry.

  • 3.
    Andrén, Maria Norevik
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Gothenburg University, Sweden.
    Kvarnemo, Charlotta
    Stockholm University, Faculty of Science, Department of Zoology. Gothenburg University, Sweden.
    Filial cannibalism in a nest-guarding fish: females prefer to spawn in nests with few eggs over many2014In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 68, no 10, p. 1565-1576Article in journal (Refereed)
    Abstract [en]

    In fish, fecundity correlates with female body size and egg-tending males often eat small broods. Therefore, small females may prefer to spawn in nests that already contain many eggs, to ensure the brood is as large as possible. In contrast, large females may prefer nests with few eggs, if high egg number or density has a negative effect on egg survival, or if there are drawbacks of spawning last in a nest. To test the hypothesis that female body size affects nest (and male mate) choice, using the sand goby (Pomatoschistus minutus), we allowed small and large females to choose between two males that were matched in size - one guarding a small clutch and the other a large clutch, respectively. We recorded where females spawned (measure of female preference), the combined brood size, male courtship, egg care and nest building. We also quantified the effect of brood size and egg density on egg survival in a separate data set. Although the combined broods did not exceed the small brood sizes that are at risk of being eaten, both small and large females preferred to spawn in nests with smaller clutch sizes. This preference could not be explained by more courtship or male parental effort, nor by reduced survival of larger or denser broods. Instead, our result might be explained by females avoiding the danger of cannibalism of young eggs by males or the risk of reduced egg health associated with being near the nest periphery.

  • 4.
    Berger, David
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Time stress, predation risk and diurnal-nocturnal foraging trade-offs in larval prey.2008In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 62, no 10, p. 1655-1663Article in journal (Refereed)
    Abstract [en]

    Insect larvae increase in size with several orders of magnitude throughout development making them more conspicuous to visually hunting predators. This change in predation pressure is likely to impose selection on larval anti-predator behaviour and since the risk of detection is likely to decrease in darkness, the night may offer safer foraging opportunities to large individuals. However, forsaking day foraging reduces development rate and could be extra costly if prey are subjected to seasonal time stress. Here we test if size-dependent risk and time constraints on feeding affect the foraging–predation risk trade-off expressed by the use of the diurnal–nocturnal period. We exposed larvae of one seasonal and one non-seasonal butterfly to different levels of seasonal time stress and time for diurnal–nocturnal feeding by rearing them in two photoperiods. In both species, diurnal foraging ceased at large sizes while nocturnal foraging remained constant or increased, thus larvae showed ontogenetic shifts in behaviour. Short night lengths forced small individuals to take higher risks and forage more during daytime, postponing the shift to strict night foraging to later on in development. In the non-seasonal species, seasonal time stress had a small effect on development and the diurnal–nocturnal foraging mode. In contrast, in the seasonal species, time for pupation and the timing of the foraging shift were strongly affected. We argue that a large part of the observed variation in larval diurnal–nocturnal activity and resulting growth rates is explained by changes in the cost/benefit ratio of foraging mediated by size-dependent predation and time stress.

  • 5.
    Bergström, Jonas
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Enfjäll, Karin
    Determinants of mating rate in a butterfly.In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762Article in journal (Refereed)
  • 6. Boström, Jannika E.
    et al.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Åkesson, Susanne
    Northern magnetic displacements trigger endogenous fuelling responses in a naive bird migrant2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 5, p. 819-821Article in journal (Refereed)
    Abstract [en]

    In a previous study, we found that juvenile northern wheatears (Oenanthe oenanthe) exposed to a magnetic displacement to the west of their natural migration route increased their body mass. The total intensity and inclination used for the western displacement may also have been interpreted as northern compared to the experimental site (stronger total field intensity and steeper inclination angle). In order to investigate whether the fuelling response was a response to an unexpected magnetic field or specific to the northern magnetic field, we conducted a new experiment. Juvenile wheatears from the same study population were magnetically displaced to southwestern magnetic fields, exposing the birds to unexpected magnetic combinations, but eliminating the possible effect of a northern magnetic field. A control group was kept in the local geomagnetic field in Sweden for comparison. There was no difference in body mass increase between treatments, suggesting that the fuelling response previously found was not a simple response to an unexpected magnetic field, but rather a specific response to the northern magnetic field. Juvenile wheatears may have developed a fuelling response to northern magnetic fields in order to enable a successful flight towards the migration goal.

  • 7. Boström, Jannika
    et al.
    Fransson, Thord
    Henshaw, Ian
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Åkesson, Susanne
    Autumn migratory fuelling: a response to simulated magnetic displacement in juvenile wheatears, Oenathe oenathe2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, no 11, p. 1725-1732Article in journal (Refereed)
    Abstract [en]

    Recent experiments exposing migratory birds to altered magnetic fields simulating geographical displacements have shown that the geomagnetic field acts as an external cue affecting migratory fuelling behaviour. This is the first study investigating fuel deposition in relation to geomagnetic cues in long-distance migrants using the western passage of the Mediterranean region. Juvenile wheatears (Oenanthe oenanthe) were exposed to a magnetically simulated autumn migration from southern Sweden to West Africa. Birds displaced parallel to the west of their natural migration route, simulating an unnatural flight over the Atlantic Ocean, increased their fuel deposition compared to birds experiencing a simulated migration along the natural route. These birds, on the other hand, showed relatively low fuel loads in agreement with earlier data on wheatears trapped during stopover. The experimental displacement to the west, corresponding to novel sites in the Atlantic Ocean, led to a simulated longer distance to the wintering area, probably explaining the observed larger fuel loads. Our data verify previous results suggesting that migratory birds use geomagnetic cues for fuelling decisions and, for the first time, show that birds, on their first migration, can use geomagnetic cues to compensate for a displacement outside their normal migratory route, by adjusting fuel deposition.

  • 8.
    Corral-López, Alberto
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Garate-Olaizola, Maddi
    Stockholm University, Faculty of Science, Department of Zoology.
    Buechel, Severine D.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology.
    Kotrschal, Alexander
    Stockholm University, Faculty of Science, Department of Zoology.
    On the role of body size, brain size, and eye size in visual acuity2017In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 71, no 12, article id UNSP 179Article in journal (Refereed)
    Abstract [en]

    The visual system is highly variable across species, and such variability is a key factor influencing animal behavior. Variation in the visual system, for instance, can influence the outcome of learning tasks when visual stimuli are used. We illustrate this issue in guppies (Poecilia reticulata) artificially selected for large and small relative brain size with pronounced behavioral differences in learning experiments and mate choice tests. We performed a study of the visual system by quantifying eye size and optomotor response of large-brained and small-brained guppies. This represents the first experimental test of the link between brain size evolution and visual acuity. We found that female guppies have larger eyes than male guppies, both in absolute terms and in relation to their body size. Likewise, individuals selected for larger brains had slightly larger eyes but not better visual acuity than small-brained guppies. However, body size was positively associated with visual acuity. We discuss our findings in relation to previous macroevolutionary studies on the evolution of brain morphology, eye morphology, visual acuity, and ecological variables, while stressing the importance of accounting for sensory abilities in behavioral studies.

  • 9.
    Henshaw, Ian
    et al.
    Uppsala universitet.
    Fransson, Thord
    Naturhistoriska riksmuseet, ringmärkningscentralen.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Geomagnetic field affects spring migratory direction in a long distance migrant2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, no 8, p. 1317-1323Article in journal (Refereed)
  • 10.
    Kaby, Ulrika
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    What limits predator detection in blue tits (Parus caeruleus): posture, task or orientation2003In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 54, no 6, p. 534-538Article in journal (Refereed)
    Abstract [en]

    To detect threats and reduce predation risk prey animals need to be alert. Early predator detection and rapid anti-predatory action increase the likelihood of survival. We investigated how foraging affects predator detection and time to take-off in blue tits (Parus caeruleus) by subjecting them to a simulated raptor attack. To investigate the impact of body posture we compared birds feeding head-down with birds feeding head-up, but could not find any effect of posture on either time to detection or time to take-off. To investigate the impact of orientation we compared birds having their side towards the attacking predator with birds having their back towards it. Predator detection, but not time to take-off, was delayed when the back was oriented towards the predator. We also investigated the impact of foraging task by comparing birds that were either not foraging, foraging on chopped mealworms, or foraging on whole ones. Foraging on chopped mealworms did not delay detection compared to nonforaging showing that foraging does not always restrict vigilance. However, detection was delayed more than 150% when the birds were foraging on whole, live mealworms, which apparently demanded much attention and handling skill. Time to take-off was affected by foraging task in the same way as detection was. We show that when studying foraging and vigilance one must include the difficulty of the foraging task and prey orientation.

  • 11.
    Kolm, Niclas
    Uppsala universitet, Zooekologi.
    Female courtship in the Banggai cardinalfish: honest signals of egg maturity and reproductive output?2004In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 56, no 1, p. 59-64Article in journal (Refereed)
    Abstract [en]

    Despite the vast literature on male courtship behaviour, little is known about the function and information content of female courtship behaviour. Female courtship behaviour may be important in many species, particularly where both sexes invest heavily in the offspring, and if such behaviours contain honest information regarding a female’s potential reproductive investment, they may be particularly important in male mate choice. Using observations of two female courtship behaviours (the “rush” and the “twitch”) from experimental pairings in the Banggai cardinalfish (Pterapogon kauderni), I addressed the question of whether these courtship behaviours contained information on female reproductive output (clutch weight) and egg maturity (proximity to spawning), traits commonly associated with male mate choice. I especially focused on the importance of these courtship behaviours in relation to other female characters, such as size and condition, using multiple regression. I found that one of these behaviours, the rush, was strongly associated with fecundity, whereas size, condition and the twitch were not. Further, I found that the “twitch” behaviour was associated with how close to actual spawning a female was. The results suggest that female courtship behaviour may convey highly important information in a mate choice context. I discuss the adaptive value of honest information in female courtship behaviour in light of these results.

  • 12.
    Kotrschal, Alexander
    et al.
    Uppsala universitet, Zooekologi.
    Rogell, Björn
    Uppsala universitet, Zooekologi.
    Maklakov, Alexei A.
    Uppsala universitet, Zooekologi.
    Kolm, Nichlas
    Uppsala universitet, Zooekologi.
    Sex-specific plasticity in brain morphology depends on social environment of the guppy, Poecilia reticulata2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 11, p. 1485-1492Article in journal (Refereed)
    Abstract [en]

    The vertebrate brain is a remarkably plastic organ, which responds quickly to environmental changes. However, to date, studies investigating plasticity in brain morphology have focused mostly on the physical properties of the surrounding environment, and little is known about brain plasticity in response to the social environment. Moreover, sex differences in brain plasticity remain virtually unexplored. Here, we tested how the social environment influenced brain morphology in adult males and females using experimental manipulation of the sex composition of social pairs (same sex vs. mixed sex) in the guppy (Poecilia reticulata). We detected substantial sex-specific plasticity in both the overall brain size (controlling for body size) and separate brain structures. The brain size was larger in males that interacted with females, and female optic tectum was larger in female-only groups. Overall, females had larger olfactory bulbs and cerebellum in comparison to males. While net sexual dimorphism in the brain structure can be explained in light of the known differences in boldness and foraging behaviour between the sexes, our results also support that cognitive demands associated with courtship behaviour can lead to plastic changes in the brain size. Our findings demonstrate that not only social environment can generate rapid, plastic responses in the vertebrate brain but also that such responses can depend strongly on sex.

  • 13.
    Larsdotter Mellström, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Friberg, Magne
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Borg-Karlson, Anna-Karin
    KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry.
    Murtazina, Rushana
    KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry.
    Palm, Mikael
    KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Seasonal polyphenism in life history traits: Time costs of direct development in a butterfly2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, p. 1377-1383Article in journal (Refereed)
    Abstract [en]

    Insects with two or more generations per year will generally experience different selection regimes depending on the season, and accordingly show seasonal polyphenisms. In butterflies, seasonal polyphenism has been shown with respect to morphology, life history characteristics and behaviour. In temperate bivoltine species, the directly developing generation is more time-constrained than the diapause generation and this may affect various life history traits, such as mating propensity (time from eclosion to mating). Here we test whether mating propensity differs between generations in Pieris napi, along with several physiological parameters, for males sex pheromone synthesis, and for females ovigeny index and fecundity.

    As predicted, individuals of the directly developing generation – who have shorter time for pupal development - are more immature at eclosion; males take longer to synthesize the male sex pheromone after eclosion and also take longer to mate than diapause generation males. Females show the same physiological pattern, the directly developing females lay fewer eggs than diapausing females during the first days of their life. Nevertheless, the directly developing females mate faster after eclosion than diapausing females, indicating substantial adult time stress in this generation and possibly an adaptive value of shortening the pre-reproductive period.

    Our study highlights how time-stress can be predictably different between generations, affecting both life history and behaviour. By analyzing several life history traits simultaneously we adopt a multi-trait approach to examining how adaptations and developmental constraints likely interplay to shape these seasonal polyphenisms.

  • 14.
    Larsdotter Mellström, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Different mating expenditure in response to sperm competition risk between generations in the bivoltine butterfly Pieris napi2015In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 69, no 7, p. 1067-1074Article in journal (Refereed)
    Abstract [en]

    Examining how the response to sperm competition risk varies in a population is essential in order to understand variation in reproductive success and mating system. In polyandrous butterflies, males transfer a large spermatophore at mating that delays female remating and confers an advantage in sperm competition. However, as large ejaculates are costly to produce—male expenditure on ejaculate size should be selected to vary with risk of sperm competition, as previously shown in the butterfly Pieris napi. In P. napi, adults can either emerge after winter diapause, or they can emerge as a directly developing generation later in the summer. Post-diapause adults have fewer developmental constraints because direct developers have to grow, develop, emerge, mate, and reproduce during a more limited seasonal timeframe, and as a result are more time-stressed. The two generations show polyphenisms in a variety of traits including polyandry, pheromone production, mating propensity, and sexual maturity at eclosion. Using these within-species, between generation differences in ecology, we generated three important findings: (1) that both generations respond to an immediate risk of elevated sperm competition and significantly raise ejaculate investment, (2) that the diapausing generation raises this investment by a far greater 65 % increase compared with the direct generation males’ 28 %, and (3) that males show a graded response relative to sperm competition risk and increase their ejaculate investment in relation to the actual level of mate competition. The difference in male mating allocation between generations may help explain life history evolution and geographic differences in mating patterns.

  • 15.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Reduced take-off ability in robins due to migratory fuel load1999In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 46, no 1, p. 65-70Article in journal (Refereed)
    Abstract [en]

    Recent studies have shown that large fuel loads in small birds impair flying ability. This is the first study to show how migratory fuel load affects flying ability, such as velocity and height gained at take-off in a predator escape situation, in a medium-distance migrant, and whether they adjust their take-off according to predator attack angle. First-year robins (Erithacus rubecula) were subjected to simulated attacks from a model merlin (Falco columbarius), and take-off velocity and angle were analysed. Robins with a wing load of 0.19 g cm−2 took off at a 39% lower angle than robins with a wing load of 0.13 g cm−2, while velocity remained unaffected. The robins did not adjust their angle of ascent in accordance with the predator's angle of attack. Since many predators rely on surprise attacks, a difference in flight ability due to varying fuel loads found in migrating robins can be important for birds' chances of survival when actually attacked.

  • 16.
    Lindenfors, Patrik
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Tullberg, Birgitta
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Biuw, Martin
    Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife KY16 8LB, Scotland.
    Phylogenetic analyses of sexual selection and sexual size dimorphism in pinnipeds2002In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 52, p. 188-193Article in journal (Refereed)
  • 17.
    Lissåker, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kvarnemo, Charlotta
    Ventilation or nest defence – Parental care trade-offs in a fish with male care2006In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 60, no 6, p. 864-873Article in journal (Refereed)
    Abstract [en]

    Brood guarding animals face many critical trade-offs. Sand goby males (Pomatoschistus minutus) build nests with larger openings during low oxygen conditions, presumably to enhance ventilation. However, this may make the nest easier for egg predators to detect and harder for guarding males to defend. Manipulating oxygen level and predator presence (a small crab) for small and large males, we found support for a parental trade-off between fanning and nest defense. An increased fanning activity resulted in less time for guarding. Small males and males in low oxygen showed a higher fanning expenditure than large males and males in high oxygen, but surprisingly, filial cannibalism did not differ between these groups. Males built larger nest openings in low than high oxygen. However, males in both high and low oxygen treatments reduced their nest opening size in the presence of a predator, again indicating an important trade-off between ventilation and nest defense.

  • 18.
    Olofsson, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Auditory defence in the peacock butterfly (Inachis io) against mice (Apodemus flavicollis and A. sylvaticus)2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 2, p. 209-215Article in journal (Refereed)
    Abstract [en]

    Morphological and behavioural traits can serve as anti-predator defence either by reducing detection or recognition risks, or by thwarting initiated attacks. The latter defence is secondary and often involves a 'startle display' comprising a sudden release of signals targeting more than one sensory modality. A suggested candidate for employing a multimodal defence is the peacock butterfly, Inachis io, which, by wing-flicking suddenly, produces sonic and ultrasonic sounds and displays four large eyespots when attacked. The eyespots make small birds retreat, but whether the sounds produced thwart predator attacks is largely unknown. Peacocks hibernate as adults in dark wintering sites and employ their secondary defence upon encounter with small rodent predators during this period. In this study, we staged predator-prey encounters in complete darkness in the laboratory between wild mice, Apodemus flavicollis and Apodemus sylvaticus, and peacocks which had their sound production intact or disabled. Results show that mice were more likely to flee from sound-producing butterflies than from butterflies which had their sound production disabled. Our study presents experimental evidence that the peacock butterfly truly employs a multimodal defence with different traits targeting different predator groups; the eyespots target birds and the sound production targets small rodent predators.

  • 19.
    Partridge, C
    et al.
    Texas A&M University, USA.
    Ahnesjö, I
    Uppsala universitet.
    Kvarnemo, Charlotta
    Stockholm University, Faculty of Science, Department of Zoology.
    Mobley, KB
    Texas A&M University, USA.
    Berglund, A
    Uppsala universitet.
    Jones, A
    Texas A&M University, USA.
    The effect of perceived female parasite load on post-copulatory male choice in a sex-role-reversed pipefish2009In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, p. 345-354Article in journal (Refereed)
    Abstract [en]

    The last several decades of research in behavioral ecology have resulted in a deeper appreciation of post-mating processes and sexual conflict in sexual selection. One of the most controversial aspects of sexual selection is cryptic mate choice. Here, we take advantage of male pregnancy in a sex-role-reversed pipefish (Syngnathus typhle) to quantify cryptic choice based on perceived parasite load and other sources of variance in female fitness. Studies have shown that S. typhle males preferentially mate with females with lower parasite loads and that a male's perception of female parasite load can be altered by tattooing females. We manipulated the apparent parasite load of females in controlled mating experiments to test the hypothesis that post-copulatory sexual selection is dependent on a male's perception of female parasite load in pipefish. Our results provided no evidence for cryptic male choice based on perceived female parasite load. However, we found evidence that eggs from larger females were more likely to result in viable offspring than eggs from smaller females and that the first female to mate with a male transferred more eggs per copulation on average. Overall, our results show that potential for post-copulatory sexual selection does exist in pipefish, but the male's perception of female parasite load does not play a major role in this process.

  • 20. Ramp, Christian
    et al.
    Hagen, Wilhelm
    Palsböll, Per
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Berube, Martine
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Sears, Richard
    Age-related multi-year associations in female humpback whales (Megaptera novaeangliae)2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, no 10, p. 1563-1576Article in journal (Refereed)
    Abstract [en]

    Analyses of social structures in baleen whales are rare, and so far, they are thought to consist of mostly short and unstable associations. We investigated the association patterns of individual humpback whales from a summer feeding aggregation in the Gulf of St. Lawrence from 1997 to 2005. Photo-identified animals were sexed using genetic methods and were grouped into five categories: juvenile males/females, mature males and lactating/non-lactating females. We calculated half-weight association indices within and between the groups and found that 45% of the observation showed single animals and another 45% small groups (two to three) consisting mainly of mature animals besides lactating females. Using permutation tests, we found evidence for long-term associations between mature males and non-lactating females as well as among non-lactating females. Standardised lagged association rates revealed that these male-female groups disassociated quickly over about 2 weeks, whereas associations increased again towards the beginning of the breeding season. Non-lactating females of similar age engaged in multi-seasonal stable pairs for up to six consecutive feeding seasons; no mature male-female association was observed in consecutive years. The females with the most stable and long-term associations also had the highest reproductive output. While the risk of predation could not explain these long-term bonds, feeding cooperation seemed the most plausible explanation for group forming behaviour during the summer months.

  • 21. Sol, Daniel
    et al.
    Maspons, Joan
    Gonzalez-Voyer, Alejandro
    Stockholm University, Faculty of Science, Department of Zoology. Universidad Nacional Autónoma de México, Mexico.
    Morales-Castilla, Ignacio
    Zsolt Garamszegi, László
    Møller, Anders Pape
    Risk-taking behavior, urbanization and the pace of life in birds2018In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 72, no 3, article id UNSP 59Article in journal (Refereed)
    Abstract [en]

    Despite growing appreciation of the importance of considering a pace-of-life syndrome (POLS) perspective to understand how animals interact with their environment, studies relating behavior to life history under altered environmental conditions are still rare. By means of a comparative analysis of flight initiation distances (i.e., the distance at which an animal takes flight when a human being is approaching) across > 300 bird species distributed worldwide, we document here the existence of a POLS predicted by theory where slow-lived species tend to be more risk-averse than fast-lived species. This syndrome largely emerges from the influence of body mass, and is highly dependent on the environmental context. Accordingly, the POLS structure vanishes in urbanized environments due to slow-lived species adjusting their flight distances based on the perception of risk. While it is unclear whether changes in POLS reflect plastic and/or evolutionary adjustments, our findings highlight the need to integrate behavior into life history theory to fully understand how animals tolerate human-induced environmental changes. Significance statement Animals can often respond to changing environmental conditions by adjusting their behavior. However, the degree to which different species can modify their behavior depends on their life history strategy and on the environmental context. Species-specific perception of risk is a conspicuous example of adjustable behavior tightly associated with life history strategy. While there is a general tendency of higher risk aversion in rural than city-dwelling birds, it is dependent on the species' life history strategy. Slow-lived species are more prone to adjust their flight initiation distances based on the perception of risk, allowing humans to approach closer in urban than rural environments. Behavior must therefore be taken into account together with life history to reliably assess species' vulnerability at the face of ongoing environmental change.

  • 22. Sundin, Josefin
    et al.
    Amcoff, Mirjam
    Stockholm University, Faculty of Science, Department of Zoology. University of Texas, USA.
    Mateos-Gonzalez, Fernando
    Raby, Graham D.
    Jutfelt, Fredrik
    Clark, Timothy D.
    Long-term exposure to elevated carbon dioxide does not alter activity levels of a coral reef fish in response to predator chemical cues2017In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 71, no 8, article id UNSP 108Article in journal (Refereed)
    Abstract [en]

    Levels of dissolved carbon dioxide (CO2) projected to occur in the world's oceans in the near future have been reported to increase swimming activity and impair predator recognition in coral reef fishes. These behavioral alterations would be expected to have dramatic effects on survival and community dynamics in marine ecosystems in the future. To investigate the universality and replicability of these observations, we used juvenile spiny chromis damselfish (Acanthochromis polyacanthus) to examine the effects of long-term CO 2 exposure on routine activity and the behavioral response to the chemical cues of a predator (Cephalopholis urodeta). Commencing at similar to 3-20 days post-hatch, juvenile damselfish were exposed to presentday CO2 levels (similar to 420 mu atm) or to levels forecasted for the year 2100 (similar to 1000 mu atm) for 3 months of their development. Thereafter, we assessed routine activity before and after injections of seawater (sham injection, control) or seawater-containing predator chemical cues. There was no effect of CO2 treatment on routine activity levels before or after the injections. All fish decreased their swimming activity following the predator cue injection but not following the sham injection, regardless of CO2 treatment. Our results corroborate findings from a growing number of studies reporting limited or no behavioral responses of fishes to elevated CO2. Significance statement Alarmingly, it has been reported that levels of dissolved carbon dioxide (CO2) forecasted for the year 2100 cause coral reef fishes to be attracted to the chemical cues of predators. However, most studies have exposed the fish to CO2 for very short periods before behavioral testing. Using long-term acclimation to elevated CO2 and automated tracking software, we found that fish exposed to elevated CO2 showed the same behavioral patterns as control fish exposed to present-day CO2 levels. Specifically, activity levels were the same between groups, and fish acclimated to elevated CO2 decreased their swimming activity to the same degree as control fish when presented with cues from a predator. These findings indicate that behavioral impacts of elevated CO2 levels are not universal in coral reef fishes.

  • 23.
    Svensson, Ola
    et al.
    University of Gothenburg Department of Zoology .
    Lissåker, Maria
    Stockholm University, Faculty of Science, Department of Zoology.
    Mobley, Kenyon B.
    3.Umeå University Department of Ecology and Environmental Science .
    Offspring recognition and the influence of clutch size on nest fostering among male sand gobies, Pomatoschistus minutus2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, no 8, p. 1325-1331Article in journal (Refereed)
    Abstract [en]

    When parental care is costly, parents should avoid caring for unrelated young. Therefore, it is an advantage to discriminate between related and unrelated offspring so that parents can make informed decisions about parental care. In the present study, we test the hypothesis that male sand gobies (Pomatoschistus minutus) recognize and differentially care for their own offspring when given a choice between a nest with sired eggs and a second nest with eggs sired by an unrelated male. The sand goby is a species with exclusive and costly paternal care. Male parasitic spawnings (e.g., sneaking) as well as nest takeovers by other males are common. Our results show that nests containing sired eggs were preferred and received significantly more care, as measured by nest building and nest occupancy, than nests with foreign eggs even when males cared for both nests. These findings suggest that males respond to paternity cues and recognize their own clutches. Relative clutch size also had a significant effect on male parental care. When sired clutches were larger than foreign clutches, males preferred to care for their own nest. In the few cases where males chose to take care of foreign nests, the foreign clutch was larger than their own clutch. Taken together, our results provide evidence that both paternity cues and clutch size influence parenting decisions among male sand gobies.

  • 24. Vallin, Adrian
    et al.
    Dimitrova, Marina
    Stockholm University, Faculty of Science, Department of Zoology.
    Kodandaramaiah, Ullasa
    Stockholm University, Faculty of Science, Department of Zoology.
    Merilaita, Sami
    Deflective effect and the effect of prey detectability on anti-predator function of eyespots2011In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 65, no 8, p. 1629-1636Article in journal (Refereed)
    Abstract [en]

    Eyespots (patterns of roughly concentric rings) are often thought to have an anti-predator function. Previous experiments have lent support for the intimidation hypothesis by demonstrating a deterring effect of eyespots, but so far there is little evidence for the deflective effect (direction of attacks toward less vital body parts). We studied predators' responses towards large and small eyespots and towards prey with no, one, or a pair of eyespots and if this response is influenced by whether or not prey blend into background. In two experiments, we used artificial, triangular prey items and blue tits (Cyanistes caeruleus) as predators. In experiment 1, we found evidence for the deflective effect of small but not large eyespots, independent of whether the prey was presented on a concealing or exposing background. In experiment 2, we found that predators avoided the prey with a pair of small eyespots more than the prey without eyespots, but interestingly, we only found this deterring effect on the concealing background. There was no difference in attacks between the prey with one large and two small or one large and no eyespots. We conclude that deflective function may select for eyespots, and background may influence the deterring function of eyespots.

  • 25.
    Vallin, Adrian
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    An eye for an eye – on the generality of the intimidating quality of eyespots in a butterfly and a hawkmoth2007In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 61, no 9, p. 1419-1424Article in journal (Refereed)
    Abstract [en]

    Large eyespots on the wings of butterflies and moths have been ascribed generally intimidating qualities by creating a frightening image of a bird or mammal much larger than the insect bearing the eyespots. However, evidence for this anti-predator adaptation has been largely anecdotal and only recently were peacock butterflies, Inachis io, shown to effectively thwart attacks from blue tits, Parus caeruleus. Here we test whether large eyespots on lepidopterans are generally effective in preventing attacks from small passerines, and whether the size of insect or bird can influence the outcome of interactions. We staged experiments between the larger eyed hawkmoths, Smerinthus ocellatus, and the smaller peacock butterflies, I. io, and the larger great tits, Parus major, and the smaller blue tits, P. caeruleus. Survival differed substantially between the insect species with 21 of 24 peacocks, but only 6 of 27 eyed hawkmoths, surviving attacks from the birds. Thus, surprisingly, the smaller prey survived to a higher extent, suggesting that other factors than insect size may be important. However, great tits were less easily intimidated by the insects’ eyespots and deimatic behaviour and consumed 16 of 26, but the blue tits only 8 of 25 of the butterflies and hawkmoths. Our results demonstrate that eyespots per se do not guarantee survival, and that these two insects bearing equally large eyespots are not equally well protected against predation.

  • 26.
    Wiklund, Christer
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Vallin, Adrian
    Stockholm University, Faculty of Science, Department of Zoology.
    Friberg, Magne
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Rodent predation on hibernating peacock and small tortoiseshell butterflies2008In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 62, no 3, p. 379-389Article in journal (Refereed)
    Abstract [en]

    Insects that hibernate as adults have a life span of almost a whole year. Hence, they must have extraordinary adaptations for adult survival. In this paper, we study winter survival in two butterflies that hibernate as adults and have multimodal anti-predator defences-the peacock, Inachisio, which has intimidating eyespots that are effective against bird predation, and the small tortoiseshell, Aglais urticae, which does not have an effective secondary defence against birds. We assessed predation on wild butterflies hibernating in the attic of an unheated house, as well as survival of individually marked butterflies placed by hand on different sites in the attic. Our objectives were to assess (1) the number of butterflies that were killed during hibernation, (2) whether survival differed between butterfly species, and (3) how predation was related to hibernation site and the identity of the predator. There was a strong pulse of predation during the first 2 weeks of hibernation: 58% of A. urticae and 53% of I. io were killed during this period. Thereafter, predation decreased and butterfly survival equalled 98% during the final 16 weeks of hibernation. There was no difference in survival between the two butterfly species, but predation was site-specific and more pronounced under light conditions in locations accessible to a climbing rodent, such as the common yellow-necked mouse, Apodemus flavicollis. We contend that small rodents are likely important predators on over-wintering butterflies, both because rodents are active throughout winter when butterflies are torpid and because they occur at similar sites

  • 27. Zidar, Josefina
    et al.
    Balogh, Alexandra
    Stockholm University, Faculty of Science, Department of Zoology. Linköping University, Sweden.
    Favati, Anna
    Stockholm University, Faculty of Science, Department of Zoology.
    Jensen, Per
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology.
    Sorato, Enrico
    Løvlie, Hanne
    The relationship between learning speed and personality is age- and task-dependent in red junglefowl2018In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 72, no 10, article id 168Article in journal (Refereed)
    Abstract [en]

    Cognition is fundamental to animals’ lives and an important source of phenotypic variation. Nevertheless, research on individual variation in animal cognition is still limited. Further, although individual cognitive abilities have been suggested to be linked to personality (i.e., consistent behavioral differences among individuals), few studies have linked performance across multiple cognitive tasks to personality traits. Thus, the interplays between cognition and personality are still unclear. We therefore investigated the relationships between an important aspect of cognition, learning, and personality, by exposing young and adult red junglefowl (Gallus gallus) to multiple learning tasks (discriminative, reversal, and spatial learning) and personality assays (novel arena, novel object, and tonic immobility). Learning speed was not correlated across learning tasks, and learning speed in discrimination and spatial learning tasks did not co-vary with personality. However, learning speed in reversal tasks was associated with individual variation in exploration, and in an age-dependent manner. More explorative chicks learned the reversal task faster than less explorative ones, while the opposite association was found for adult females (learning speed could not be assayed in adult males). In the same reversal tasks, we also observed a sex difference in learning speed of chicks, with females learning faster than males. Our results suggest that the relationship between cognition and personality is complex, as shown by its task- and age-dependence, and encourage further investigation of the causality and dynamics of this relationship.

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