Mammalian Biology最新文献

Based on principles of natural selection, high-quality individuals may benefit by selecting mates of similar phenotypic quality when given the opportunity; that is, individuals may benefit by engaging in a form of non-random mating referred to as positive assortative mating. In ungulates, the idea of mate selectivity is still highly debated, with few studies providing evidence of positive assortative mating. In white-tailed deer (Odocoileus virginianus), recent studies have suggested minimal mate selectivity based on phenotypic characteristics. However, findings from these previous studies may be due to the fact that study populations had young age structures and female skewed sex-ratios that may have limited opportunities for preferential mating. From 2008 to 2019 we studied a captive population of white-tailed deer to examine characteristics of 184 parental pairs that successfully recruited fawns, while the population underwent changes in age structure and sex ratio, and we found evidence of non-random mating in parental pairs. Specifically, for each 1-year increase in male age there was a 0.32-year increase in female age among parental pairs, and for every 1.00 cm increase in male skeletal body size there was a 0.18 cm increase in female skeletal body size. We also observed that as the male and female age structures increased over time, the slope of the relationship between male and female lifetime body percentiles of parental pairs had a greater positive increase over time. Furthermore, we observed that breeding success by younger males decreased as the age structure matured. Although, even with evidence for non-random mating, we were unable to firmly conclude these findings as assortative mating due to the fact we still observed cases where there was a large difference in age between mates, indicating some plasticity with mating. Overall, our results suggest that individuals of an older age and greater body size may select for individuals of a similar condition if provided with the opportunity. However, choosiness appears dynamic, with a decrease in selectivity when preferential mates are limited due to a young age structure or when mating opportunities decrease for poor competitors in a population with a mature age structure.

A species’ diet niche is shaped by the evolutionary processes of adaptation to the available food resources in its habitat and by competition with ecologically similar species. In the European Alps, Alpine mountain hares (Lepus timidus varronis) and European hares (Lepus europaeus) occur parapatrically along the elevation gradient and hybridise with each other in overlapping areas. Evidence that the areas of overlap are not stable suggests that interspecific competition between the two congeneric hare species is strong. Competitive exclusion might take place at a fine spatial scale and influence the feeding behaviour of the two hare species. In this study, we investigated diet ecology of Alpine mountain hares, European hares and their hybrids in the Alps in the middle and at the end of the plant vegetation growth period by collecting hare faeces along the altitudinal gradient in Grisons (Switzerland). We performed genetic analysis to identify the hare species and analysed the faeces microscopically to determine dietary composition. Plant components at the level of dicotyledons/monocotyledons, plant family and plant species in faeces of 49 European hares, 16 Alpine mountain hares and 22 hybrids (with discordant nuclear and mitochondrial genetic backgrounds) were identified. Alpine mountain hares used significantly more Ericaceae as food plants than European hares and hybrids. As mountain hares support phenolics in the nutrition better than European hares, our results suggest that the diet of the two lagomorph species are affected by phenolics content in the Alpine ecosystem. Our findings underline the Alpine mountain hare’s adaptation to the Alpine ecosystem by using characteristic Alpine vegetation as food plants. The phenolics tolerance and specialist feeding strategy might be a decisive advantage of the Alpine mountain hare in the competition between the two lagomorph species in the Alps.

Today’s biodiversity was strongly impacted by glacial cycles during the Pleistocene. They generated species diversity and population structuring, which can easily remain undetected, if populations differentiation is not accompanied by divergence in external morphological traits. This phenomenon, described as cryptic diversity, has been intensively researched in bats, which are known to harbour cryptic phylogenetic lineages. Many studies however have a regional focus or suffer from geographical gaps. Widely understudied areas include Central and Western Asia, although they connect the western and eastern Palearctic fauna. These areas are characterized by topographic heterogeneity and therefore high ecosystem diversity. In this study we investigated the phylogeography of the Savii’s pipistrelle (Hypsugo savii), a bat species assumed to be widely distributed across the Palaearctic. We compiled published sequences from four mitochondrial genes (ND1, CytB, COI and 16 S), added new sequences especially from the Asian part of the distribution range and performed phylogenetic and phylogeographic analyses. They indicate that H. savii is a taxonomic unit with extensive cryptic diversity, comprising at least four major mitochondrial lineages with allopatric or parapatric distribution ranges. Divergence time dating reveals the impact of Pleistocene glaciations on shaping highly structured populations of a highly mobile mammal across the Palearctic. Our study also revealed several zones of secondary contact among populations where hybridization and gene flow likely occur. This study highlights the necessity for studying biodiversity in Western and Central Asia in order to understand biogeographic patterns, evolutionary processes and conservation needs in the area that connects eastern and western Palearctic faunas.

Determining sex in Cervidae species is crucial for wildlife management, conservation, breeding programs, disease surveillance, and forensic investigations. While existing genetic sexing methods have proven effective, they often involve time-consuming and resource-intensive processes. In response to the growing need for a more efficient and cost-effective technique, this study aimed to develop a novel loop-mediated isothermal amplification (LAMP) method for sex detection in various deer species. We designed LAMP primers specific to Cervidae based on sex chromosome-located genes, AmelogeninX, and SRY. Analytical specificity was confirmed using 108 samples from red deer, roe deer, and fallow deer, and species specificity was also tested in other deer and mammal species. Sex determination results were fast (40 min) and accurate (100% reliability). This technique has the advantage of allowing researchers to identify the sex of different deer species using the same method. Using the isothermal amplification properties of LAMP, this new method provides a simple, quick, and accurate tool to help researchers, wildlife managers, and forensic investigators with important sex-related questions in cervid populations.

Sonations are non-vocal acoustic signals whose production mechanisms have been rarely investigated in mammals. Since sonations are directly tied to specific anatomical characteristics, one issue in acoustic communication studies is estimating the morphological diversity of the structures responsible of sound emission. The nocturnal and social habits of the African crested porcupine make them an ideal model to address this issue. Both sexes bear highly specialised quills on their tail that, by colliding against each other, produce a sound (rattling). We measured the quills of 130 subjects and found that their morphology did not vary in relation to season and sex. Compared to subadults (N = 39) and adults (N = 81), cubs (< 6 months, N = 10) have fewer and stubbier rattle quills that also differ in their length and diameter across the age classes. The passage from the cub to the subadult phase seems to sign the most important changes in the quill development. Although it is unknown when and how often a cub produces rattling, the presence of quills at a very early stage of life indicates that they can potentially be used. Although several hypotheses can explain the potential role of cub rattling, one of the most reasonable is that, when olfactory and/or visual contacts are prevented, this sound can alert adults about potential predation risks on offspring. Matching morphological and acoustic data under different contexts will allow understanding the correlates at the basis of the potential roles of such a peculiar way of communication.

One of the most fascinating mammalian range expansions in Europe involves an opportunistic mesocarnivore―the golden jackal (Canis aureus). However, key questions about the origins and dispersal strategies of pioneering individuals, likely the first to establish new populations, remain unanswered. We analyzed genetic data from three golden jackals found at the forefront of the expansion, reaching the Iberian Peninsula (Spain) and Fennoscandia (Finland and Norway, beyond the Arctic Circle). We genotyped two tissue samples and one fecal sample using 15 microsatellites and compared results with an extensive reference dataset. Additionally, we analyzed the mtDNA control region (HVR1) for two individuals. All individuals were males, identified as pure jackals and first-generation migrants. Our results suggested either western Pannonia (1650 km distance) or, less probably, the Adriatic region (1300 km) as the region of origin for the Spanish individual, also western Pannonia for the Finnish individual (2500 km), and the Baltics or the Caucasus for the Norwegian individual (1400 km to 3400 km). These sources represent abundant core populations or relatively recent and successfully colonized areas. Both the Spanish and Finnish individuals carried the prevalent H1 HVR1 haplotype in Europe, confirming matrilineal genetic uniformity on the continent. The recent expansion of C. aureus is fueled by several sources, showcasing the golden jackals’ remarkable ability for long-distance dispersal as they extend their range to northernmost and westernmost Europe. Our findings highlight the dynamic nature of wildlife distribution, providing insights into species movement across vast distances amidst climatic, environmental, and anthropogenic pressures.

Despite the common destructive effects of urbanisation on biodiversity assemblages, certain species thrive in urban environments. One mammalian species that has persisted in the urban-forest mosaic landscape is the vervet monkey (Chlorocebus pygerythrus). It is a common resident primate in Durban, eThekwini Municipality, KwaZulu-Natal Province, South Africa, with frequent contact with humans and domestic wildlife. Due to their adaptability in using human-altered landscapes, the interactions between humans and vervet monkeys have increased and are often negative. Our study determined trends in the admission cases of vervet monkeys to a Durban wildlife rehabilitation centre and assessed the main factors contributing to these admissions to mitigate human-vervet monkey conflict. Our analyses were conducted on recorded admission data for vervet monkeys at a wildlife rehabilitation centre from 2011 to 2018. Members of the public (90.0%) mostly reported vervet cases, with admissions mostly recorded from the central district (46.8%) of the municipality. The number of admitted vervet monkeys increased significantly over the years and months, with a mean (± SE) of 127.3 ± 21.34 and 84.8 ± 5.37, respectively. Only 34.3% of vervet monkeys were alive at the end of the admission process from the 83.7% that were admitted alive at the rehabilitation centre. The high number of deaths resulted from anthropogenic activities, primarily motor vehicle strikes (30.8%) and domestic dog (Canis lupus familiaris) attacks (13.9%). We modelled survivability for vervet monkeys, and our results showed that season, age category, and the cause of admission were all significant factors influencing survival after admission. The sex of vervet monkeys had no significant effects on survivability after admission to the rehabilitation centre. We suggest that wildlife rehabilitation centres in priority areas use these findings in education to improve human coexistence with vervet monkeys. The trends also serve as a foundation for human-vervet conflict resolution programmes. The advantages of publishing records from rehabilitation centres are that they will raise awareness of the challenges posed by vervet monkeys in urban environments, where they are sometimes perceived as a nuisance because of anthropogenic influences in the urban mosaic landscape.

Cozumel Island is one of the most important tourist destinations in Mexico. Unfortunately, this has been associated with a deterioration of the integrity of essential habitats for native fauna, including the Critically Endangered pygmy raccoon (Procyon pygmaeus). Environmental degradation can affect, among other things, their food availability. Here we focused on examining the diet of the pygmy raccoon in two main subpopulations of the species, by analyzing scat samples and assessing (natural and anthropogenic) food availability. Scat analysis showed that crabs are the dominant component of the pygmy raccoon diet, followed by fruits. The frequency of occurrence correlates with temporal (monthly) food availability. Although anthropogenic food sources can be found in both sampling sites, the availability of natural resources was greater. A better understanding of the diet and food resources availability in their habitats is important to understand the impacts of disturbances on wildlife health, distribution, abundance, and survival.

Knowledge on the mating system of a species is central to understand population dynamics and development. Special attention has been paid to the investigation of monogamous species and evolutionary causes and advantages of this mating system. However, social monogamy does not necessarily imply also genetic monogamy. Given the rarity of genetic monogamy in mammal species and the uncertain conclusions regarding multiple paternity in Eurasian beavers (Castor fiber), here, we undertake a further attempt to clarify the genetic monogamy of Eurasian beavers studying an Austrian beaver population by genotyping of gestating females and their foetuses at 19 microsatellite loci. Microsatellite analysis of mother–offspring groups suggest the occurrence of multiple paternity at a low level: two out of 42 litters (4.8%) were sired by two different males. We discuss the occurrence of extra-pair mating and potential drivers of multiple paternity in the light of beaver biology, population densities, territory characteristics and resulting activity ranges during reproduction period. Especially in the context of increasing beaver population densities in recovering populations and related increase of human-wildlife conflicts, sound knowledge on breeding biology, including species-specific reproduction tactics and their general applicability, is important for population monitoring.

Non-flying small mammals are interesting models to study biogeographic patterns due to their low vagility and diverse distribution patterns. Gracilinanus is a genus of mouse opossums widely distributed in different South American biomes, consisting of seven species. G. agilis and G. microtarsus, show distinct habitat preferences. The former is distributed over dry open forests and the latter is restricted to the Brazilian Atlantic Forest. In this study, we utilize molecular data to reconstruct the biogeographic history of Gracilinanus and the demographic history of G. agilis and G. microtarsus through probabilistic models: DEC and ABC models. We estimated the origin of the genus in the Middle Miocene and our analyses support that the uplift of the Andes could have been one of the major drivers of diversification. Looking at the past demographic history of two widely distributed species we found evidence of recent population expansion for G. agilis but not for G. microtarsus. These results suggest that G. microtarsus was ecologically resilient to maintain its effective population sizes throughout the glacial cycles during the Pleistocene. In contrast, ecological instability was higher for G. agilis, especially in the Caatinga biome.