Ethology最新文献

Bird song contains crucial information that enables recognition of conspecific individuals from a distance, which facilitates subsequent complex behaviors related to mate attraction and rival deterrence. Loud broadcast signals of non-learning bird species are usually treated as less complex than songs of Oscines, but several studies have revealed that song learning is not necessary for the evolution of complex signaling. Here, we focused on a species of African wood-dove which produces superficially simple songs consisting of short notes organized into two parts of different amplitude. Our model was a population of emerald-spotted wood-doves (Turtur chalcospilos) that live in the same area as the physically and vocally similar blue-spotted wood-dove (Turtur afer). We tested the responses of male emerald-spotted wood-doves to different playbacks simulating territorial intrusion. We used songs of the focal species and of the congener, two types of artificially mixed songs with different parts belonging to the focal or congeneric species, and a control song. We aimed to assess (i) whether the focal species responds only to its own species' song or exhibits interspecific territoriality, and (ii) which part of the song is responsible for coding species identity. We found that male emerald-spotted wood-doves responded strongly to playback, but almost exclusively approached only the playback of their own species' song. Additionally, only conspecific song caused a decrease in song rate during playback and an increase in song output after playback. Our results suggest that emerald-spotted wood-doves are able to discriminate their own songs from those of congeners and do not exhibit interspecies territoriality. We were unable to identify a single part of the song that codes species-specificity, as mixed songs of any kind did not substantially increase responsiveness to playback in comparison to the congener song or the control. We discuss these results in the context of current hypotheses regarding interspecific territoriality and the evolution of species-identity coding.

Retraction: Pruitt, J. N., Burghardt, G. M., & Riechert, S. E. (2011). Non-conceptive sexual behavior in spiders: A form of play associated with body condition, personality type, and male intrasexual selection. Ethology, 118(1), 33–40. https://doi.org/10.1111/j.1439-0310.2011.01980.x

The above article, published online on October 23, 2011 in Wiley Online Library (wileyonlinelibrary.com) has been retracted by agreement between the Journal's Editor-in-Chief, Wolfgang Goymann, and Wiley-VCH GmbH. The retraction has been agreed upon following concerns raised about the validity of the quantitative data reported. J.N. Pruitt, the corresponding author, did not respond following repeated requests to provide the primary data. During the investigation, coauthors S.E. Riechert and G.M. Burghardt requested retraction because they would have no way to validate the article's conclusions without those data. The coauthors have lost confidence in the conclusions of the article, as have the editors and Wiley, hence our decision to retract. Corresponding author J.N. Pruitt was informed of the decision but has remained unresponsive.

Kodama, T., & Mori, A. (2023). How important is temperature for strike success of ectotherms? Thermal effects on predator–prey interactions of free-ranging pit vipers (Gloydius blomhoffii). Ethology, 129, 641–648.

In figure 2, the color of a plot (Strike outcome: “Hit”, Tb: 18.69°C, Dist.: 10 cm) is incorrect. The color of the plot should not be black but gray. The corrected figure 2 is shown below.

We apologize for this error.

Body size is often a critical determinant of competitive ability and reproductive behavior. For example, small males characteristically lose contests with larger males and may be metabolically constrained from sustaining energetically demanding reproductive behaviors. Small males thus often utilize alternative reproductive tactics (ARTs) to maximize their reproductive success. How variation in body size among behavioral phenotypes arises can provide important insight into the maintenance of ARTs. For instance, smaller body sizes for males adopting ARTs may simply be a function of age, suggesting that the tactic is maintained by the periodic recruitment of young males into the population. Alternatively, body size differences among behavioral phenotypes that are unrelated to age suggest disparate growth rates that potentially arise as a consequence of variation in environmental conditions during development or genotypic differences between the phenotypes. Here we examine these alternative scenarios in the green treefrog, Dryophytes cinereus, using skeletochronological analysis combined with body size measures. As with many other anuran amphibians, male green treefrogs conditionally adopt a noncalling satellite mating tactic and attempt to intercept females attracted to the vocalizations of calling “host” males. We show that males adopting satellite behavior in natural choruses are smaller than calling males but do not represent a class of younger individuals, indicating that satellite males have lower growth rates than calling males. We also show that satellite males are in poorer condition than larger calling males, implicating energetic constraints in size-related variation in mating tactic expression. Our work suggests that environmental conditions during development, genetic differences between phenotypes, or both, give rise to size discrepancies in behavioral phenotypes, neither of which have been previously explored in anurans. We discuss body size and condition differences between behavioral phenotypes in the context of energetic constraints and endocrine mediation of tactic expression in this species.

Sexual selection is an important evolutionary force and despite extensive research, understanding mate choice on naturally occurring trait variation remains an intriguing area of study. The correlation between mass, a trait associated with courter viability and common target for mate choice, and signals is particularly noteworthy. This study focuses on Schizocosa mccooki, the largest member of a wolf spider genus renowned for its diverse complex male courtship. Our objective was to understand the relationship of male mass and other courtship signals on female choice within this species. We conducted lab experiments involving random pairings of field caught males and females, recording vibratory courtship and its outcomes. Our findings revealed that S. mccooki courtship consisted of vibratory signals with two major components, thumps and raps. Male mass, overall courtship vigor, and thump duration were found to predict mating success. Interestingly, we found no correlation between temporal traits and mass suggesting independent information and an absence of trade-offs between mass, courtship vigor, and signal component rates/durations. Instead, we found that heavier males tend to produce thumps with lower frequencies. The finding that male mass predicts mating success contrasts with patterns observed in other species in this well-studied genus. By uncovering the mate choice patterns of S. mccooki, this study underscores the importance of comparative studies to understand the ways in which sexual selection drives diversification, even among closely related taxa.

Carcasses are patchily distributed and often short-lived resources, placing scavenging animals under pressure to locate them before they rot or are depleted by competitors. Scavengers may search for carcasses directly, or indirectly, using social information. Aggregations of feeding animals and their conspicuous competitive behaviour may be more readily detectable to searching scavengers than the carcass itself. Moreover, the actions of attendant scavengers upon the carcass, breaking it apart and releasing odour or chemical cues, may further enhance its detectability to others foraging nearby. Here we test this idea. In the first of two experiments performed in the field, we found that hermit crabs (Pagurus bernhardus) were attracted to shelled mussels (Mytilus edulis) that other hermit crabs were already feeding on. They showed no strong tendency to approach aggregations of conspecifics in the absence of food, nor conspecifics that were confined close to mussels but prevented from feeding on them. We speculated that through breaking up the carcass, the feeding hermit crabs released chemical cues and drifting particles of mussel tissue that further attracted other hermit crabs. We tested this in a second experiment, finding that finely chopped mussels attracted significantly more hermit crabs than did intact mussels. We suggest that scavenger feeding action upon carcasses makes these more detectable to others by releasing odour and particle plumes, a form of inadvertently produced social information.

Egg retrieval is an ancient behaviour displayed by birds in which a displaced egg is transferred back into the nest. Egg rejection, in contrast, is a recently evolved adaptation by hosts of brood parasites in which an egg is removed from a nest. These conflicting behaviours are both adaptive because they prevent reproductive losses, but egg retrieval may benefit brood parasites if hosts retrieve parasitic eggs into their nests. We examined these conflicting cognitive processes in the prothonotary warbler (Protonotaria citrea), a cavity-nesting host of the brown-headed cowbird (Molothrus ater). Eggs and nestlings are occasionally found on the rims of warbler nest cavities. We determined how this happened using video cameras and tested whether warblers retrieved their own eggs more often than cowbird eggs. We also determined if shape affects retrieval and rejection by placing cylinders inside nest cups or onto nest rims. We found that eggs were displaced by rapidly departing warblers whose nests are constantly prospected by nest competitors and brood parasites. Warblers retrieved their eggs (29%) and cowbird eggs (19%) at similar rates, and never rejected cowbird eggs after retrieval. Warblers removed most cylinders from nest rims and cups (89% and 78%, respectively), and never retrieved them. Warblers have retained egg retrieval at a low level and its expression is costly because they only retrieve a low level of their own eggs and also retrieve cowbird eggs, which benefits the brood parasite.

Studies that concurrently investigate the functional benefits of group living in multiple populations of the same species are rare. Over a 3-year period (2014–2016), we examined two ecologically contrasting populations to test multiple hypotheses for the adaptive significance of group living in the communally breeding rodent Octodon degus. We quantified the size of social units (number of adults, number of adult females), edible vegetation at burrow systems, and per capita offspring weaned (PCOW) in each population. Contrary to expectations, we did not observe population-specific associations between group size and edible vegetation or PCOW nor universal benefits of group living. In one population, PCOW increased in mid-sized groups with more edible vegetation. However, this trend was not consistent across years. Notably, we observed a complete reproductive failure in one population during the first year of study, one that was characterized by low rainfall and no detectable edible vegetation. This result is important because reproductive failure occurred regardless of group size, suggesting that communal living may not buffer degus against the harshest of environmental conditions. Examining how social organization shapes individual reproductive success under extreme variation in food availability is an important step towards understanding how populations will respond to a changing climate.

How often males and females need to mate to maximize their fitness is a source of sexual conflict in animals. Sexual conflict over mating frequency can lead to antagonistic coevolution in which males employ tactics to coerce females into mating, while females resist or evade mating attempts by males. Here, we report on a novel burying behavior observed in female northern map turtles (Graptemys geographica) in Opinicon Lake, Ontario, Canada that appears to function as a tactic to avoid male detection during the mating season. Underwater videos indicated that females are heavily solicited during the mating season with over half the females being actively pursued by males. Biologgers indicated that females are less active and remain deeper than males during the mating season. Our data strongly suggest that female northern map turtles avoid intense solicitation and potential harassment by males by burying themselves in lake sediments. This behavior appears to be a low-cost solution for females to reduce the costs of resistance and mating while they are constrained to habitats with high male densities for overwintering.

Predator–prey dynamics have led to a strong selection of prey's ability to detect and respond to information about the risk environment. Further, intrinsic factors, such as sex, may cause prey to perceive and respond to information differently. Chemical alarm cues from injured conspecifics are a classic example of how prey have evolved to use publicly available information to shape their behavior and enhance fitness, yet sex-specific alarm reactions are rarely considered. The purpose of our study was to compare how males and females respond to conspecific chemical alarm cues in the livebearing fish species, Brachyrhaphis rhabdophora. Furthermore, we tested males and females from populations with a high- or low-predation environment. Brachyrhaphis rhabdophora showed strong alarm reactions, but contrary to our predictions, showed limited variation due to sex or predation environment. We found that males and females from both populations displayed lower activity levels and increased their swimming depth when exposed to an alarm cue, despite variable and consistent baseline behaviors among individuals. These data further contribute to our understanding of what factors shape the evolution of behavioral responses to chemical alarm cues in fishes.