acta ethologica最新文献

Annual killifish have an annual life cycle unique among vertebrates. Adults lay desiccation-resistant eggs in the soil of the temporary pools they inhabit. Courtship behavior of some Neotropical killifish consists of a series of displays performed by males and females that ends in the total or partial burial of the couple. However, little information exists on their reproductive isolation mechanisms, including a detailed analysis of courtship signals. In this study, we analyzed the courtship behavior of a Neotropical annual killifish (Austrolebias nigripinnis) within a comparative frame. The most frequent units in males were lateral (44%) and sigmoid displays (26%), where males exhibit morphological and color patterns to females. Females showed a high frequency (44%) of quiescence, suggesting that this unit may have an evaluative role during courtship. Behavioral units recognized in this species show some differences with other related species (i.e., Austrolebias affinis), mainly in frequency and duration, but also in sequence. Although the results of this work cannot determine if these differences constitute reproductive isolation mechanisms, it provides fundamental elements to try to establish kinship relationships and solve the complexity implicit in the definition of species.

While the use of trees has been widely documented for most of the big cats, this information is scant for the jaguar (Panthera onca). In this study, we investigated the use of trees by jaguars, evaluating different underlying reasons as well as the frequency of tree use based on sex, age, and reproductive status. Data were obtained from 2013 to 2020 through a combination of direct observations during fieldwork and camera trapping focused on this behavior in the Brazilian Pantanal. We documented 252 climbing events (176 direct observations, 76 camera captures). Using only camera trapping data to avoid observers’ influence on jaguar behavior, we fitted generalized linear mixed models (GLMM) with jaguar identity as a random factor to test the effects of age, sex, and presence of conspecifics in the odds of animals climbing trees. We also used a generalized linear model (GLM) to test the effect of adult body weight on jaguar tree climbing probability. Age and presence of conspecifics were the most important drivers of jaguar climbing behavior in the study area, with cubs being more likely to climb trees than adults of either sex (odds ratio = 7.91, p < 0.001), and the presence of conspecifics, irrespective of age and sex, accentuated that behavior (odds ratio = 3.26, p < 0.005). Adult females (especially the lighter ones) and cubs were commonly recorded through direct observation on trees, a similar trend to our GLMM that showed a marginally negative effect of body weight on jaguar tree climbing probability. Only a few adult male jaguars ascended trees, and in all cases, these males were following females in heat. We suggest that trees are vertical extensions inside jaguar home ranges and may be safe refuges for resting and for protecting offspring against potential threats, including the harassment of large adult males.

Abstract

Abstract

Animals whose ecological niches largely overlap within a habitat can get into intra-specific and/or inter-specific competition for some of the limited resources available. We hypothesise that differences in locomotor abilities might be a key component deciding which individual will gain the resource, especially in animals with limited agility, such as turtles. To address this hypothesis, we tested self-righting ability and releasing from a vegetation alike rope in two sympatric populations of turtles: Emys orbicularis and Mauremys rivulata. All individuals managed to complete the tests promptly (≤ 103 s). When overturned on their carapace, E. orbicularis had shorter inspecting time, as well as overturning time, indicating slight advantage in self-righting. On the other hand, both species were equally efficient to release from a rope attached to the front of their plastron. The inter-specific morphological differences indicate that muscular strength might be a good predictor of competitive relations among syntopic turtle species.

Toe-tapping, the quick movement of the middle toes of the hind legs, has been observed in many frogs and toads, and is usually associated with feeding, calling, or courtship behaviors. While plenty of observations of toe-tapping exist for different species, experimental evidence regarding the stimuli triggering this behavior is almost non-existent. Here, we systematically tested the influence of different stimuli on the toe-tapping behavior in the green-and-black poison frog (Dendrobates auratus, Dendrobatidae) from a captive colony in the Zoo Frankfurt. We found that, compared to a control, both big and small prey animals (crickets and fruit flies) elicited much more toe-tapping behavior, and that toe-tapping was positively correlated to feeding events. Playback advertisement calls in contrast did not trigger toe-tapping. We further showed that also juvenile frogs already toe-tap, but less frequently than adults. Our results support the observation-based data that toe-tapping is associated with hunting behaviors. While the auditory part of courtship does not seem to trigger toe-tapping, experimental evidence regarding visual and/or tactile courtship stimuli is still lacking.

The addax antelope (Addax nasomaculatus) is a species under serious threat of extinction, as it is more abundant in captivity than in the wild. However, little is known about its basic biology. The aims of this study were to determine how locomotor, feeding, aggressive, marking, and sexual behavior of male addax allocated in all-male groups vary with season and with female contact (i.e., biostimulation). The study was conducted in captive conditions, in two groups of adult males: one with no-physical contact with females, aside from visual and olfactory interactions (CF group, n = 4), and another group completely isolated from females (IF group, n = 4). The frequency of behaviors was recorded during the daytime, 4 days per season (total time of observation = 256 h). Lying, standing, walking, aggressive, marking, grazing, and ruminating behaviors as well as water and supplement consumptions varied with season (all p < 0.05). The lying, walking, marking, grazing, and ruminating behaviors were more frequently observed for CF than IF males (all p < 0.05). Also, all behaviors, except for marking, varied with the interaction between the group and seasons (all p < 0.05). Sexual behavior was extremely scarce, so it was not possible to analyze how it varied with seasons and the group. The present study suggests that management program and housing conditions, especially in ex situ breeding plans, should consider the influence of the season and the sociosexual context on the behavior of addax males.