Journal of Zoology最新文献

Yámanas (coastal) and Selknams (inland) were among the early Holocene Indigenous groups on the Switzerland-sized island of Tierra del Fuego at the southern tip of South America. Companion to both cultures was the extinct, zoologically mysterious and ‘domesticated’ Fuegian Dog. The objective here was to conduct an interdisciplinary-bibliometric analysis of widely scattered records by historical explorers, artists and scientists from the middle 1700s to early 1900s for a characterization of this canid species, its origin and relationship with Indigenous peoples. This is a rare glimpse into the historical past, especially because both the ‘dog’ and people are extinct. Historical references in the 1800s described live Fuegian Dogs as fox-like in appearance and behavior. Art renditions of the dog from early visitors to the island during James Cook's and FitzRoy-Darwin's expeditions 200 years ago illustrated fox-like canids. In fact, recent analyses of a dog-museum specimen revealed that it was genetically equivalent to the wild Culpeo Fox (Lycalopex culpaeus) of South America. Supporting this evidence are more than 160 words and phrases related to ‘dog’ in the Yámana language, suggesting this animal was long an integral part of their culture. Archaeological finds of paleo-pet foxes in Europe, North America and South America with human-like diets and/or shared burials suggest a close relationship with Indigenous cultures. Due to the absence of Domestic Dogs in the archaeological records of Tierra del Fuego and extreme southern Patagonia, as well as its tenuous relationship with Indigenous groups, its fox-like morphological characteristics, half-wild behavior, highly unusual food habits of marine shell fish, and driving of fish into trap nets, it is proposed that this canid was not a domesticated dog, but a semi-tame companion of Indigenous peoples, best described as a Fuegian Pet Fox (Lycalopex culpaeus).

Predator–prey interactions occur within the context of relative prey abundance, the nutritional value of prey individuals, and their specific vulnerability to predation. Predation patterns can therefore be expected to vary between seasons, age and sex categories, with this variation important for understanding predator–prey ecology. We examined seasonal prey selection by snow leopards (Panthera uncia) on different age and sex categories of Siberian ibex (Capra sibirica) using data collected from 150 kill sites. These were analysed in relation to known ibex population composition using Jacobs' index, which estimates the strength and direction of prey preference or avoidance. Although solitary felids typically select prey of similar or smaller size than themselves, both male and female snow leopards selected for prime-aged ibex males (>5 years old), despite these being at least twice their body mass. Female ibex, yearlings and medium-sized males, which are similar in size to snow leopards, were preyed upon less than expected. In spring, snow leopards increased their prey selection of females and newborn kids, and reduced their selection of prime males. Our results suggest that the vulnerability of ibex to snow leopard predation is related to their agility in negotiating steep mountain terrain. We propose that the much larger body size of prime-aged ibex males reduces their ability to evade snow leopard ambushes on mountain slopes. In spring, the switch to predation on kids likely relates to the ease of hunting because of their lower agility, with a similar explanation for increased predation on females in late gestation. This seasonal switching between different prey categories, and the snow leopard's specialisation to hunt in steep mountainous terrain, may impose limits on sexual size dimorphism commonly seen in other large felids. In contrast, the vulnerability of prime-aged ibex males to snow leopard predation may reflect a sexually selected handicap, imposed by high sexual size dimorphism.

The success of parthenogenic populations is facilitated by high fecundity, though studies show that parthenogenic hybrids can express traits of compromised fitness compared with their parent species, such as higher rates of evaporative water loss and greater susceptibility to ectoparasites. Recent works highlighting the importance of microbiomes on host health also show that both host lineage and the environment contribute to an animal's microbiome. In this study, we investigated how reproductive mode and the presence of mites affect evaporative water loss and if the skin bacterial microbiome differs between sympatric sexual and parthenogenic populations of the gecko Heteronotia binoei in central Australia. We collected sexual (n = 17) and parthenogenic (n = 66) H. binoei from six local sites (within 3 km of each other) to measure evaporative water loss, record mite infestations, and characterise skin bacterial communities from a subsample of individuals (n = 17 per reproductive mode). Only parthenogenic individuals had mites, and mite infestations were not severe at our site. We found that neither reproductive mode nor the presence of mites affected evaporative water loss in our study populations, contrary to prior studies elsewhere for the species. In microbiome analyses, we found that reproductive mode significantly predicted community structure and composition; however, local site explained more of the observed variation than other variables. While these findings challenge previously observed differences in physiology between parthenogenic and sexual H. binoei, we found support for ectoparasite susceptibility in parthenogenic individuals. Our microbiome results reinforce that even in sympatry, host lineages harbour unique microbiomes, although the environment largely influences the skin bacterial communities in our study system.

Self and conspecific recognition allows many animals to effectively navigate complex social environments. However, these discriminatory abilities come with substantial sensory and neurological costs and therefore should be more prevalent in populations where recognizing self-other and individual cues is essential. Populations on islands may experience reduced benefits from self and conspecific recognition due to the distinct ecological and social conditions of insular life (e.g. high population densities, decreased territoriality, minimal hybridization risk, challenging signalling environment). To test this hypothesis, we compared the discriminatory abilities for self and conspecific chemical recognition of mainland and island Italian wall lizards (Podarcis siculus), a species much dependent on chemoreception. We sampled lizards from three locations on the Italian mainland and three Adriatic islands and assessed their tongue flick behavior when confronted with water (control), their own odour, or that of conspecifics. Our results indicated that both mainland and island lizards could discriminate between their own scents and those of other individuals within their population, as well as between two distinct individuals, as evidenced by significant increases in tongue-flick rates. This indicates self-other and conspecific recognition on the basis of chemical cues, in both mainland and island populations. However, we do find some evidence of chemosensory deprivation in the island populations, as increases in tongue flick rates were lower in island lizards compared to mainland lizards. In addition, island lizards tongue flicked at much lower rates than mainland lizards, suggesting a reduced use of the chemosensory channel in insular conditions. Nevertheless, if insular lizards have a chemosensory deficiency, it does not seem to jeopardize self and conspecific chemical recognition.

Insects represent the most megadiverse animal group, having evolved a wide range of feeding strategies. Among them, dung beetles stand out for their specialization in exploiting decomposing organic matter, particularly excrements. In the Iberian Peninsula, dung beetles typically feed on various types of dung produced by large herbivorous mammals. However, when different types of dung are available, they tend to show a predilection for the most valuable one. In addition, studies using non-native dungs are lacking. Therefore, the aim of this study was to assess whether an Iberian dung beetle community may be attracted to specific dung types, including those from exotic fauna. Fieldwork was carried out in Mataelpino, a town located in Central Spain (Madrid, Spain). A total of six different dungs were used, from animal species with different feeding strategies and geographic origins: African forest buffalo, Asian elephant, brown bear, goat, fallow deer and wild boar. To determine whether dung beetles exhibit attraction for particular dung types, different statistical analyses were carried out on the data collected from field sampling. The results show that dung beetle species behave mostly as generalists, utilizing all the excrements tested. However, it was observed that there were clear preferences for certain types of excrement, notably elephant dung, which is exotic to the region. Buffalo and wild boar dungs were also highly attractive, whereas goat dung exhibited the lowest attractiveness. In conclusion, Iberian dung beetles display a generalist diet although they may exhibit attraction towards specific excrements, including those of exotic origin.

Predator–prey interactions can be viewed as an evolutionary arms race influenced by environmental factors. A common anti-predator strategy, known as aposematism, relies on the coupling of warning signals with secondary (e.g., chemical) defences to deter predators. The European fire salamander (Salamandra salamandra) is an emblematic, aposematic amphibian of the Biosphere Reserve Wienerwald (BRWW), a forest region where both protected areas and areas with forest management can be found. Differences between these areas are likely to affect the structure of predator communities and, in turn, their interactions with prey. Fire salamanders have a distinct yellow and black warning colouration and skin toxins that provide protection from predators, and the amount of yellow in their dorsum is negatively correlated with predation attempts. Here, we compare predation rates on clay models of fire salamanders with the same amount of dorsal yellow colouration distributed across either many small or few large markings, and placed in either protected or managed zones of the BRWW. We observed no differences in predation rates based on marking size, as all models were attacked with similar frequency. However, we found that bird attacks were more frequent in managed forest zones than in protected ones. The main differences between these forest zones were in tree diversity and evenness. We suggest that forest structure and complexity may lead to differences in either abundance or composition of predator communities which, in turn, might influence attack rates. Finally, we highlight the importance of protected zones as potential havens for fire salamanders and propose further research to test specifically the effect of differences in predator community composition on predation risk across forest zones.

Maratus marinus (Salticidae) is a marine-associated jumping spider that lives on pebble beaches. It can be found in the intertidal zone, exposing it to inundation, hydraulic forces and saltwater. We investigated aspects of M. marinus's behaviour and physiology that may allow it to exploit this zone. Firstly, we determined the propensity for spiders to flee or remain within their nests when facing submersion. We found that nest structure affected behaviour: spiders in densely constructed nests remained in their nests, spiders in the flimsiest nests fled from the water, while those in medium-density nests either fled or, if they remained, appeared to spin silk, possibly to improve waterproofing. Additionally, we determined that spiders in nests submerged under water for 1 h continued to respire, as oxygen levels within these nests decreased over time, but hypoxia was minimal. Finally, we compared the heart rates M. marinus with Trite planiceps, a larger fully terrestrial salticid from a nearby habitat. Trite planiceps had a faster maximum heart rate (230 bpm) compared with M. marinus (175 bpm). Hearts rates in both species declined when left undisturbed for an hour. Using heart rate data as a proxy of metabolic rate, we suggest that M. marinus has a lower metabolic rate compared with T. planiceps. Our findings support the notion that, at the very least, M. marinus has behavioural adaptations enabling it to exploit the intertidal environment.

Anemones are prominent members of marine ecosystems; however, of the 15 000 species of marine fishes, only 13 are documented to feed substantially on anemones. Preying on anemones may require specialized phenotypes to overcome their nematocyst-lined tentacles and elastic material properties. Here, we investigated whether Clinocottus globiceps, one of the few anemone-feeding fishes, has behavioral and morphological adaptations for consuming anemones. We used high-speed videography to describe the behaviors of C. globiceps and syntopic sculpins feeding on anemones and shrimp. We then compared the feeding apparatus of five trophically diverse sculpins using micro-computed tomography and scanning electron microscopy. We also used histology to investigate potential defense mechanisms for resisting nematocysts. We found that C. globiceps used a distinct combination of twisting and bending to rip anemone tentacles, compared to just the pulling or just rolling behaviors used by all species to feed on shrimp. Both C. globiceps and its algivorous sister species, C. recalvus, had robust jaws, large jaw muscles, and rows of blade-like teeth suited for biting that contrasted with the suction-feeding morphology of benthic invertivores. Clinocottus globiceps also had thicker epithelia around the mouth, which may act as a shield against nematocysts. We propose that the morphologies of C. globiceps that aid in anemone-feeding are likely exapted from algivory. We also emphasize the important role of behavior in facilitating trophic novelty.

Sexual size dimorphism (SSD) in lizards is often explained through two main evolutionary strategies: fecundity selection in females reflected in differences in abdomen length (being bigger in females) and male–male competition reflected in differences in head and body size (greater in males). However, in lizards with fossorial lifestyles, sexual dimorphism is often lacking or reduced, likely due to the constraints imposed by burrowing. In the present study, we studied the sexual size and shape dimorphism in the small semi-fossorial skink Ablepharus kitaibelii. Our results show a significant size dimorphism with females being larger than males in all subspecies examined. Moreover, we found differences between sexes in both relative head and abdomen size reflecting both fecundity selection and male–male competition. Females have more elongate and wider abdomens, allowing them to carry up to 5 large eggs, whereas males have bigger heads likely related to male–male aggression and territoriality. Overall, our results suggest that despite the possible constraints imposed by burrowing, in semi-fossorial species, the SSD can evolve. Future studies on other semi-fossorial and fossorial species are needed to test the generality of these results.

Mimic species vary widely in how faithfully they resemble their models. On coral reefs, several species of the family Blenniidae mimic the bluestreak cleaner wrasse, Labroides dimidiatus (Labridae), which removes ectoparasites from other fishes, enabling the mimics to approach and bite parts of fish bodies undetected. The false cleanerfish, Aspidontus taeniatus, and bluestriped fangblenny, Plagiotremus rhinorhynchos, are well-known blennies that feed on fins, scales, and mucus of other fishes while exhibiting aggressive mimicry of the cleaner wrasse. The former (a perfect mimic) exhibits elaborate mimetic features throughout its life history, whereas the latter (an imperfect mimic) shows mimetic traits only facultatively. We conducted three-dimensional (3D) video recordings of their predatory foraging behaviors in the wild using an underwater stereo video system. Our study focused on three blenniid species, including the piano fangblenny, P. tapeinosoma, a non-mimic blenny with similar feeding habits. Our results showed that the false cleanerfish (perfect mimic) employed a “sneaky” tactic, slowly approaching small target fish and biting their caudal fins from a short distance. By contrast, the piano fangblenny (non-mimic) employed a “hit-and-run” tactic, approaching swiftly from a long distance and ripping off scales or mucus directed at the lateral body of large target fish. The bluestriped fangblenny, which exhibits lower mimetic fidelity (imperfect mimic), employed an intermediate tactic, approaching from a moderate distance between that of a perfect mimic and a non-mimic and ripping off scales or mucus of medium-sized fish. These findings suggest that differences in predatory tactics may have corresponded to the evolution of mimetic fidelity in aggressive mimic blennies.