Journal of Zoology最新文献

Understanding feeding behaviour of large carnivores is crucial for unveiling how adaptations to human-modified landscapes can alter their behaviour and ecological role. In this study, we investigated wolf feeding activity during winter through interpretative field surveys of 454 clusters of GPS locations obtained from 8 wolves in the Abruzzo, Lazio, and Molise national Park (central Italy, 2008–2011). Using generalized linear mixed models, we explored spatio-temporal use of feeding sites (i.e. kill and scavenging sites) accounting for the effect of ecological and anthropogenic factors. We detected feeding activity in 18.1% of the investigated GPS clusters, with 51.5% of the inspected feeding sites indicating scavenging on domestic prey. Wolves used feeding sites for an average of 2.4 days and revisited them about 3 (±2.7) times before being abandoned. Prey type (wild vs. domestic) and wolf category (i.e. solitary floaters, newly established breeding pairs, pack members) affected both prey handling time and recurrency of feeding site use. Pack members (≥3 wolves) spent relatively more time at feeding sites, especially those featuring large prey, and visited them more frequently compared to solitary floaters and wolf pairs. Although wolves used feeding sites mostly during the night, nocturnality significantly decreased with increasing distance to roads but not to settlements. We also revealed that time of cluster formation, number of visits, and mean slope best predict the presence of a feeding site at a GPS cluster. Despite the inclusion of scavenging sites and domestic prey, and limited to prey ≥15 kg, our predictive model would have revealed 62% of the feeding sites in the GPS clusters we investigated, while reducing of about 59% the field time required for ground truthing GPS clusters.

Previous work has focused on how prey availability and fear of people affect apex predators' habitat selection, but few have studied the effects of intraguild interactions. Patterns of co-occupancy between sympatric carnivores have started to be well described, but understanding the underlying habitat selection processes is lacking. We evaluated whether the risk of encountering African lions (Panthera leo) influences habitat selection by spotted hyaenas (Crocuta crocuta, hyaena hereafter) using GPS-collar data and two approaches: (1) resource selection functions considering the static long-term risk of encountering lions, and (2) step selection functions considering the dynamic, immediate risk of encountering lions. We explored the interplay between the risk of encountering lions, vegetation type and moonlight illumination, and examined individual variation in habitat selection. As expected, hyaenas did not avoid areas intensively used by lions, and there was even a positive effect of the long-term risk of encountering lions on habitat selection by hyaenas. As in other study sites, this likely arises because hyaenas select the same areas as lions. At the finer scale, unexpectedly, hyaenas did not generally move away from lions. We believe this occurs because hyaenas can sometimes be attracted to lions because of scavenging opportunities or because they outnumber lions and are likely to win an aggressive encounter. These two circumstances can lead to highly contrasting outcomes and highlight the high dynamics of intraguild interactions. This also illustrates the limits of GPS-based studies that lack crucial information about the context of interactions. While at the population level, we detected a selection for open vegetation areas, which are rich in prey in the study ecosystem and potentially good hunting grounds for cursorial predators, such as hyaenas; our results show a very high inter-individual heterogeneity underlying this population level result. Our work therefore illustrates the importance of investigating individual habitat selection.

The ability of animals to find shelter is vital for survival, providing protection from predators and harsh conditions. In lab studies, animals often favor walls and corners, suggesting a natural inclination toward enclosed spaces for safety reasons. Here, we investigated how shelter characteristics, specifically its size and corner angles, affect usage by the red flour beetle, Tribolium castaneum, a cosmopolitan pest of stored products, as well as the beetle's movement. The beetles remained longer in narrow shelters than in medium-sized shelters, with no significant difference from wide shelters. They spent less time in obtuse-angled corners than in right-angled ones, and more time in acute-angled corners than in right-angled ones, indicating their ability to differentiate among corners and choose suitable ones. Next, we examined whether movement through a corridor is delayed more strongly by the presence of obstacles forming acute angles with walls than by obstacles forming obtuse angles. Although there was no difference in the proportion of arrivals at the destination cell or the time required to cross the corridor, acute-angled obstacles caused a higher frequency of reentries into the origin cell, possibly due to the beetles' tendency to follow walls. This research may have applied importance, such as enhancing our understanding of beetle movement, strategies to delay their arrival in new areas, and the optimal placement of traps.

Armadillos are considered important ecosystem engineers as their burrows can benefit many species. Monitoring burrows with camera traps allows us to obtain relevant biological data on the species that utilize this resource. Our goal in this study was to examine the lesser anteater's (Tamandua tetradactyla) use of giant armadillo (Priodontes maximus) burrows as a first attempt to assess how user species benefit from them. We took camera trap data from a long-term monitoring study (2011–2020) in the Brazilian Pantanal wetland. We then evaluated and classified the frequency and way in which the burrows were used by the individual lesser anteaters. We also assessed the time of entrance and exit from the burrows related to sleep, the period of activity and activity pattern. This species used most monitored burrows, and these were used more than once by the same individuals or by more than one individual at different times. We described four types of uses: inspection of the burrow entrance, inspection of the interior of the burrow, exploratory/resting and sleeping. The lesser anteater was active on average 7 h 42 m per day with a primarily nocturnal activity pattern, which started in the early evening and ended at dawn. This is the first study to evaluate a focal species' use of giant armadillo burrows. Our data suggest that burrows are a valuable resource for the lesser anteater as shelter. Burrow monitoring proved to be effective in obtaining records and key information on the ecology and behaviour of the lesser anteater. New studies may explore this approach to acquire data on other species who frequently use these burrows, including agoutis, tayras, ocelots and coatis.

Secondary contact is a key evolutionary event in understanding biodiversity formation. Elucidating the spatiotemporal effects of sex-specific behavioural patterns on gene flow associated with secondary contact provides valuable perspectives into population dynamics of organisms. The red fox (Vulpes vulpes) is highly dispersible and adaptable, possessing the broadest natural distribution range among the Carnivora. The Hondo red fox (V. v. japonica) is an endemic subspecies inhabiting three predominant islands of the Japanese Archipelago and is believed to have experienced secondary contact between eastern and western ancestral populations after the Last Glacial. Because their dispersal patterns exhibit sexual dimorphism characterised by male mobility and female philopatry, patrilineal and matrilineal genes are expected to reflect different aspects of the distributional fusion process. Here, we estimated the phylogeographic structure based on 11 Y-chromosome-specific microsatellite loci using 50 males and compared it to that based on mitochondrial DNA (mtDNA) sequences from 153 individuals. The phylogeny of Y-chromosomal DNA (yDNA) diverged into two clades with a high support rate and was analogous to that of mtDNA. However, no phylogeographic pattern was observed in yDNA, unlike mtDNA, which exhibited a distinct east–west structuring. In contrast to mtDNA clades, both yDNA clades were distributed across the three islands. These findings indicate that secondary contact of paternal lineages progressed earlier (prior to island segmentation through marine transgression in the post-glacial stage) and more broadly than that of maternal lineages. Historical east–west vicariance probably isolated not only females but also males over a long duration, resulting in similar phylogenetic divergence between yDNA and mtDNA. Subsequently, male-biased dispersal likely enhanced gene flow between the ancestral populations, whereas female natal philopatry restricted it. This study offers crucial insights into the evolutionary dynamics of terrestrial mammals with sex-specific life histories and underscores the significance of incorporating multifaceted markers in phylogeographic studies.

Comparative analysis of nonflight morphologies can give important insight into the early ancestral origin of bats by revealing locomotor adaptations that may have predated wings. Because the scapula of bats is not directly involved in flight mechanics but does retain a primary role in walking and climbing, morphological analysis may help resolve if the ancestor to bats was arboreal or terrestrial as well as if bats are indeed monophyletic. We compared the scapulae of species representing the body mass range of Old World fruit bats (Pteropodidae) with those spanning the body mass range and diverse diets of New World fruit bats (Phyllostomidae), with a focus on the subfamily Stenodermatinae whose members have very similar niches to pteropodids. Because we were interested in scapular traits associated with climbing versus walking, we analyzed characters known to differentiate arboreal from terrestrial primates, in both contemporary and extinct lineages. We hypothesized that the scapulae of both fruit bat families would show similar adaptations, either for terrestrial or arboreal locomotion, especially if they were derived monophyletically. We found that pteropodids scapulae showed overall adaptations associated with climbing and suspensory locomotion similar to arboreal primates, whereas phyllostomids possessed character states indicating terrestrially adapted scapular morphology. Comparing the scapulae of contemporary species with the scapulae from full-bodied fossil bats from the Eocene and Oligocene epochs showed alignments that may depict the evolutionary underpinnings of each group's adaptations.

The harsher environment of higher altitudes increases selection for biparental care and increases extrinsic mortality, both of which are expected to reduce the strength of sexual selection. The intensity of sexual selection is often studied using sexual dimorphism as a proxy, especially sexual dichromatism. In birds, multiple studies have shown that sexual dichromatism decreases with increasing altitude. However, those studies have either used small datasets or have used human scoring of sexual dichromatism, potentially missing out on significant levels of cryptic dichromatism. This study includes the measure of subjective sexual dichromatism of the Vorobyev-Osorio colour discrimination model of sexual dichromatism in 758 species of bird with UV-sensitive visual systems and tests whether a relationship exists between altitude and sexual dichromatism. We found a significant positive relation between altitude and sexual dichromatism when accounting for the UV-sensitive vision of Passeriformes, Charadriiformes, Psittaciformes and Struthioniformes, but not when dichromatism is measured using human scoring. This suggests that there might be a greater selection pressure for females to select high-quality males in harsher, higher altitude, environments and that this signalling is primarily done in the ultraviolet range. We suggest that macroecologists should pay closer attention to the receiver psychology of signals even when studying a large number of species and that not doing so could lead to misleading or spurious macroecological and/or macroevolutionary patterns.

Globally, with the continuous increase in human populations, land use is changing at an unprecedented rate. Little is known about how African reptiles respond to urbanization. We used mark-resight and baited camera traps to compare population density and demographics of Nile monitors (Varanus niloticus) on a gradient of land use, namely a golf course, a farm and a nature reserve in KwaZulu-Natal, South Africa, during 2022–2023. We also collected detailed morphometrics on 112 Nile monitors throughout KwaZulu-Natal. We compared morphometric data on limbs, head, body and mass to establish whether the different ecological factors in urban and rural environments and associated behavioural shifts have resulted in unique phenotypes. No significant morphometric differences were found, but urban individuals were generally smaller and lighter than their rural counterparts. Population size estimates varied between sites. Overall, population size estimates increased with anthropogenic disturbance between our three focal sites, while the mean estimated snout-vent length decreased. The naïve presence of competing diurnal mammals did not follow a specific pattern. The overall insignificant variations in morphometrics in urban and rural areas of KwaZulu-Natal suggest that Nile monitors have adapted to urban mosaic landscapes with natural and managed (e.g. gardens, parks, golf courses, etc.) green spaces but are not as successful as some urban-exploiting varanids globally. Future research should investigate Nile monitor interactions with people and pets as well as conflict mitigation strategies.

Quantification of faecal glucocorticoid metabolites (fGCMs) is a popular non-invasive technique for monitoring wildlife's response to stressors, demanding an understanding of the stability of fGCM concentrations post-defaecation to ensure comparability of determined fGCM values across samples. To provide species-specific recommendations for the duration within which sampling can take place, we measured the rate at which the fGCM concentrations of nine different species changed throughout a 7-day period post-defaecation. In this study, we explored the temporal dynamics of fGCM concentrations in nine species across three feeding classes (ruminants, hindgut fermenters and carnivores): impala (Aepyceros melampus), giraffe (Giraffa camelopardalis), blue wildebeest (Connochaetes taurinus), plains zebra (Equus quagga), African elephant (Loxodonta africana), white rhino (Ceratotherium simum), cheetah (Acinonyx jubatus), spotted hyena (Crocuta crocuta) and leopard (Panthera pardus). Utilizing enzyme immunoassays already established for each of the focal species, we identified broader feeding class-specific patterns. All herbivores exhibited a significant decrease in fGCM concentrations over time, starting from 6 h (impala) to 48 h (giraffe, blue wildebeest, white rhino and African elephant) post-defaecation. For carnivores, concentrations remained fairly comparable for 12–24 h, after which fGCM concentrations either decreased (spotted hyena), increased (leopard) or remained stable (cheetah), with notable variation in triplicate concentrations (cheetah and leopard). These findings offer insights into scheduling faecal sampling for endocrine monitoring, particularly from free-roaming wildlife, to ensure comparability of determined hormone metabolite concentrations. Furthermore, the species-specific variation in fGCM concentration post-defaecation demonstrated in this study underlines the necessity to investigate every new species to ensure accurate and comparable results. Future studies ought to investigate how the mass of collected material, sex and drying methodologies affect the measurement of fGCMs post-defaecation.