acta ethologica最新文献

Living in complex social environments presents behavioural and cognitive challenges. A key challenge is the regulation of aggression, which may be facilitated by response inhibition, the ability to suppress inappropriate actions. In more complex social environments, greater variability in interactions may increase demands for aggression regulation, promoting the development of response inhibition. However, social instability, a form of complexity characterised by frequent changes in group composition, can elevate aggression and may instead impair inhibition. To test these competing predictions, we raised 144 chickens (Gallus gallus domesticus) in either stable or unstable social groups for five weeks. We observed the aggression within their enclosures following the final manipulation and assessed their response inhibition using a thwarting task and a cylinder task. Unstable groups initially showed more aggression than stable groups following regrouping, but this declined rapidly to the same lower level of aggression as the stable groups. Contrary to our predictions, there were no differences between birds raised in stable and unstable groups for any measure of response inhibition, and individual variation in aggression did not correlate with inhibitory performance. These findings suggest that social instability influences aggression but does not affect the development of response inhibition in chickens, highlighting the potential context- and species-specific nature of social effects on cognition.

The Japanese giant flying squirrel is an arboreal mammal that mainly eats tree leaves. Some individuals first fold the leaf in half along the midvein using the mouth and next fold it vertically with the snout while holding the leaf with the forepaw. After partial eating of the corner of the folded leaf, they drop it on the ground. This leaf debris has an eaten hole in the center. We examined such leaf debris from six areas in Japan and found that the hole was usually located on the widest part of the leaf: near the tip of apically broad leaves, the middle of centrally broad leaves, and the base of basally broad leaves. This feeding behavior can be compared to the paper craft origami. We generated a paper leaf model with a clip that resembled the flying squirrel’s forepaw and found that the paper model is folded most compactly when clipped at the widest point along midvein. The compactly folded paper facilitates the next vertical folding. Thus, the flying squirrels learn the physical properties of leaves and make a fold at the widest part of the leaf, just like in origami.

The genus Dopasia (Anguidae), native to Southeast Asia, remains poorly studied due to its elusive and secretive lifestyle; therefore, any information on its ecology and behaviour is particularly valuable. Here we present the first detailed observations of male-male combat in the genus, specifically documented in Dopasia harti (Boulenger, 1899) from Taiwan, based on unique photographic and video evidence. While male-male combat is well documented across various squamates, records from the family Anguidae are scarce and virtually absent for Dopasia. We therefore compare the ritualized behaviours observed in D. harti with those previously described in Anguis and Pseudopus. Finally, our study highlights the role of citizen science platforms in advancing field observations, biodiversity documentation, and herpetological knowledge.

Interactions between predators and prey have direct effects on the fitness of both parties. Particularly, lizards are predated by a wide variety of taxa, where birds have been proposed to exert a minor predation pressure than other vertebrates, like squamates. In general, cases among the literature report predation events where a single individual has been consumed. Here, we report the finding of seven lizards in the stomach content of a variable hawk (Geranoaetus polyosoma) road-killed in Arid Patagonia. The remains found included three adult individuals and two juveniles of Liolaemus morandae, and one adult of L. kingii, along with an additional tail. All remains showed a similar degree of digestion, which may indicate that lizards were consumed within a short timeframe. This novel finding represents the first confirmed evidence of a raptor preying simultaneously upon multiple lizard species and highlights the potential importance of lizards as dietary items of the variable hawk during the warm season in arid environments of Patagonia. Additionally, it is the first confirmed record of predation upon the Liolaemus lineomaculatus section, a group restricted to Patagonia. This predation event, including several individuals, suggests that predation pressure exerted by birds upon lizards may be underestimated, particularly in regions where other predators are scarce. We provide new information with implications for both lizard population dynamics and raptor foraging ecology, enhancing our knowledge on predator-prey interactions in Arid Patagonia.

Play behaviour in adult animals is often overlooked, particularly in free-ranging populations where it occurs less frequently than in juveniles. We investigated play behaviour and its associated behavioural sequences in urban-dwelling colonies of adult yellow mongooses (Cynictis penicillata), a species in which play has not previously been described. Using direct observations and continuous video footage, we quantified the occurrence and types of play, identified accompanying play signals and analysed the behaviours preceding and following play bouts. Play was consistently present across colonies, with social play being more frequent than either locomotor or object play. Play sessions typically began with identifiable play invitations, including play bows, which were often followed by nape bites. Behavioural sequences were analysed to describe the typical flow of actions in play events and revealed consistent patterns within and across colonies. Vigilance behaviour was more commonly observed following play bouts, suggesting a potential shift in attentional state. Our study provides one of the first detailed accounts of play in this species and contributes to a growing body of descriptive work on adult play in carnivores. These findings expand our understanding of the social behaviour of yellow mongooses and offer a baseline for future comparative studies.

The efficiency of insects in finding a suitable mate is crucial for their reproductive success. Chemical communication is primarily used to search for and recognize a potential mate. At close range, cuticular hydrocarbons (CHCs) are known to serve as mate recognition cue. In this study, we assessed the role of CHCs and social cues in mate and sex recognition through behavioral assays in ladybird beetle, Cheilomenes sexmaculata. To examine the role of CHCs in sex and mate recognition focal males were exposed to alive males and females and CHCs washed females (immersed in chloroform for 5 min, 30 min and 24 h) respectively. For social cues, males were made to encounter alive as well as dead males and females. Their copulation attempts and mating parameters (time to commence mating and copulation duration) were recorded. We also assessed whether males only mounted the dead females or copulated with them (i.e., transferred ejaculate). Our results revealed that focal males showed higher copulation attempts with alive individuals, regardless of sex. However, they attempted copulation with dead females significantly more often than with dead males. Washing of CHCs significantly influenced copulation attempts, with unwashed beetles showing a 100% attempt rate, followed by those immersed in chloroform for varying durations. Males initiated mating sooner and engaged in longer copulation with alive females compared to dead ones. Although, males mounted and copulated with dead females, no difference in sperm transfer was observed compared to alive females. Our study demonstrated that CHCs along with social cues (such as movement), play a pivotal role in eliciting male copulatory behavior.

Documented over the course of several years of scat sampling, we report on two different incidents of wild giant panda osteophagy in Sichuan Province, China. To confirm that the dense, white, fecal pellets were bone and from pandas, we sent samples to a mineralogy lab for analysis and extracted DNA. This analysis both confirmed our suspicion of osteophagy, and one sample yielded enough DNA to confirm the depositing species as giant panda. Though rare and consisting of less than 1% of collected scat samples, we posit that this behavior may constitute an important source of micronutrients for wild giant pandas.

Ladybird beetles, Propylea dissecta and Cheilomenes sexmaculata, are important biocontrol agents, preying on a variety of aphid species. These beetles often coexist and interact, and such interactions may result in reduced female fitness. To assess the impact of conspecific and heterospecific males (P. dissecta) on the reproductive output of C. sexmaculata females, we conducted three experimental treatments: control, conspecific, and heterospecific. Our results indicated that during mating, conspecific males exerted significant interference due to species similarity, disrupting mating attempts of C. sexmaculata females. Following copulation with conspecific males, a reduction in fecundity and egg viability was observed regardless of whether the females were subsequently housed with conspecific or heterospecific males. Multiple mating events occurred in the conspecific treatment, while no heterospecific mating was recorded in the heterospecific treatment. These findings suggest that both conspecific and heterospecific interactions negatively affect the reproductive success of C. sexmaculata, potentially limiting the efficacy of these beetles as biocontrol agents. Further investigation into the mechanisms driving these interspecies interactions is essential to optimise the use of these beetles in integrated pest management strategies.

Ants are social insects that inhabit nearly all terrestrial environments. In Brazil, they are widespread across diverse biomes, including the distinctive wood savannas known as Cerrado. Many species have evolved to the fire regimes in the Cerrado. Understanding the impact of fire on these species provides insights into their adaptability to altered ecological conditions. This study aimed to assess how burned areas affect on the foraging behavior of Pseudomyrmex termitarius (Smith, 1855) in the Cerrado. We conducted the research in the northeast of Brazil, specifically in Vargem Grande, Maranhão, Brazil. We studied eight ant nests from two areas: a control area and a burned area. These nests were located within 50 × 50 m continuous plots and were monitored twice daily, from 8:00 to 9:00 a.m. and from 4:00 to 5:00 p.m. We monitored temperature and humidity measurements at ground level, and the results were statistically similar between both areas. The distances traveled by ants from their nests were analyzed using the Friedman non-parametric test. Additionally, to compare the home ranges, each polygon was fragmented, and the sides of the geometric shapes were analyzed using the same test. The results showed that although the size of the home ranges for P. termitarius remained unchanged, the extent of their foraging routes was significantly larger in the burned area.