Mammalian Biology最新文献

The capybara, Hydrochoerus hydrochaeris, is a rodent that inhabits the wetlands of South America. Despite being widely distributed and having the nuclear genomes available, there has been a lack of information regarding the mitochondrial genome. To address this, we conducted the assembly and annotation of the capybara’s mitochondrial genome and reconstructed the phylogeny of Parvorder Caviomorpha. The assembly was conducted under the de novo method with GetOrganelle, while the annotation was performed with MitoZ. Analysis of relative codon synonymous usage was conducted in the mitochondrial genomes of the capybara and two other Caviidae species: Cavia porcellus and Cavia aperea. The phylogenetic inference was conducted under the Maximum Likelihood method, using the 13 protein-coding genes, including the capybara as well as other 42 Caviomorpha mitochondrial genomes. The resulting capybara mitochondrial genome consisted of 16,681 bp, 37 genes (22 tRNAs, 2 rRNAs, and 13 protein-coding genes) and a control region. The number of genes and their arrangement corresponds to the pattern observed in most mammalian species. The capybara was recovered as a sister group of Cavia. Caviidae was reconstructed as a monophyletic group that is closely related to Cuniculidae. Overall, this study provides valuable insights into the mitochondrial evolution and evolutionary relationships of the capybara.

The native savanna ecosystem of the Orinoquia region is the habitat of 50% of the wild ungulate species reported for Colombia. Over the last 20 years, this high species diversity has been strongly threatened by the human transformation of the natural land cover causing connectivity loss of the habitats. The Orinoquia region lacks a biological connectivity analysis with a multi-species approach involving species groups that are representative of the savanna ecosystem such as the ungulates. Understanding the spatial distributions of suitable areas and the main habitats that act as primary habitats for ungulate species in these landscapes is fundamental for the design of conservation strategies. We use an occurrence dataset for lowland tapir (Tapirus terrestris), white-tailed deer (Odocoileus virginianus), and white-lipped peccary (Tayassu pecari) in the development of species’ potential distribution models, binarization process, and morphological spatial pattern analysis. This information was used for the modeling of dispersal corridors connecting the core habitats of the ungulate focal species using the randomized shortest path algorithm and quantifying the weighted global connectivity metrics. Our results suggest an integral corridor with potential least-cost dispersal routes between the native savanna landscape on the middle basins of the savanna rivers and the Meta River. These areas associated with the fluvial dendritic systems are connected, while the core habitats in the eastern part of the savanna landscape are disconnected. We discuss how the application of such knowledge on the spatial ecology of ungulate focal species might improve the management of the metapopulations in the Orinoquia region.

The Swedish brown bear Ursus arctos population is protected, but managed with legally defined hunting seasons. Management decisions (e.g., hunting quotas) are frequently changed and should be based on knowledge about demographic parameters, but collecting sufficient data in the field is time consuming and expensive. An efficient method to collect data on reproductive output could be counting placental scars in the uteri of female brown bears, because hunters in Sweden are required to collect samples (including reproductive organs) of harvested bears and submit them to the authorities. We assessed the reliability of placental scar counts to determine reproductive performance by counting the number of young with female radio-collared brown bears and comparing that with placental scar counts after those females had been harvested. We found that staining uteri improved the detection of placental scars. The differences between number of scars detected before and after staining the uteri, increased significantly with female age. The number of placental scars and number of observed cubs-of-the-year accompanying females corresponded well 2 and 3 years after birth; relatively small deviations between them might have occurred because of early cub mortality prior to the observations after leaving the den. Placental scar counts can provide accurate information on age of primiparity, evidence for reproductive aging (senescence), and reproductive productivity, and therefore inform decisions regarding adaptive management, sustainable hunting, and conservation.

In this study, we describe the acoustic structure of ultrasonic alarm calls of Mongolian gerbils Meriones unguiculatus in the wild and verify these calls as belonging to Mongolian gerbils by comparison of their acoustic parameters with alarm calls recorded in captivity. Both in captivity and in the wild, the alarm calls of Mongolian gerbils represented prolonged calls with an average duration of 118 ms and a flat contour and an average maximum fundamental frequency of 26.84 kHz. We found that alarm calls of captive Mongolian gerbils were shorter and higher in fundamental frequency and followed in a quicker succession than in the wild. Although the dataset size is not sufficient to determine significant acoustic variation between the populations, we discuss the potential reasons of the acoustic differences between the ultrasonic alarm calls produced in the wild and in captivity in our study and between the alarm calls reported in literature for different captive populations. We propose a method for non-invasive estimation of occupancy of the burrows by Mongolian gerbils in fragmented colonies at very low population density, by presence of the ultrasonic alarm calls.

Especially in species with complex social systems, the relatedness between individuals is important information. Visual phenotypic cues present one way to identify closely related conspecifics. Humans are capable of recognizing such visual cues in the faces of their own as well as several primate species, but to which degree this applies to non-primate species is largely unexplored. Here we demonstrate the capability of 110 test persons to recognize faces of 47 male Asian elephants based on 186 photographs. The human examiners were not only able to recognize an individual based on its face after several years, but also to identify, at decreasing accuracy, full brother pairs and paternal kinship. People regularly working with elephants were more successful than laypersons. However, even laypersons recognized 73.3% of the same individuals. The identification of individual elephants by a look at their faces presents a simple approach which can be a valuable tool for in situ research.

Many mammals have a promiscuous mating system with multiple sired litters. Promiscuity can increase the genetic variability, reduce the risk of inbreeding, and increase the effective population size, and is therefore crucial for preventing genetic loss and maintaining adaptability. This is particularly true for small and threatened populations. The garden dormouse (Eliomys quercinus) is a threatened species, which exhibited a drastic decline over the last 20–30 years. The aim of this study was therefore to investigate the mating system of the garden dormouse in mountain forest habitat by parentage analyses using 5 polymorphic microsatellite markers combined with morphometric data and information about the nesting behavior. Genetic parentage analyses revealed that 64% (9 of 14) of the litters were sired by at least two males, suggesting that garden dormice have a promiscuous mating system. The genetic findings were further supported by indirect indicators of promiscuity, such as testes, that were nearly four times larger than predicted for a rodent of its body mass and only slight male biased sexual size dimorphism. The finding of a promiscuous mating system in garden dormice should be taken into account in future conservation efforts. Due to its habitat preferences and limited dispersal potential garden dormice are vulnerable to forest fragmentation. The connection of suitable habitats facilitates dispersal and promotes access to potential mating partners, which could be especially important for populations colonizing new habitats. Access to potential mates may also reduce inbreeding, loss of genetic variability which is crucial for populations viability and survival.

The widespread occurrence of the wild boar Sus scrofa, its controversial role in natural communities, and its close relationship with humans make this animal an important and convenient subject for studying the history and evolution of natural communities. The territory of Central Asia has been poorly represented in mammalian phylogeographic studies, namely in the case of wild boars and domestic pigs. In this study, we provide new information on wild boar genetic diversity in Central Asia in terms of mitochondrial and Y-chromosome markers and compare the set of haplotypes observed in Uzbekistan and Kazakhstan with those from other parts of the species’ range. The wild boar population in Central Asia is characterized by high uniqueness of mitochondrial and Y-chromosome markers and high haplotype diversity (as compared to other Asian regions). A maternal lineage marker (mitochondrial-DNA control region) clearly places this species in the Asian clade, whereas a paternal lineage markers (AMELY + USP9) positions it closer to wild boars from the western clade. Thus, the molecular genetic data supported the existence of a regionally specific subspecies of the wild boar: S. s. nigripes Blanford, 1875. Median-joining network analysis showed that Central Asia may be a center of dispersal and formation of S. scrofa genetic lineages in North Asia.

Detectability poses a common challenge faced by studies of small mammals. Traditional sampling methods use traps placed exclusively on the ground, which makes them less effective for monitoring species with climbing habits. The bias arising from imperfect detection may have important implications in pest assessment, epidemiological studies involving reservoirs, and conservation studies. In this study, we added above ground level (AGL) traps in the bushy or arboreal stratum to the conventional sampling protocol. Our objective was to evaluate whether the location of the traps influences the seasonal abundance pattern of Oligoryzomys flavescens, a scansorial rodent species identified as an orthohantavirus reservoir in the study area. Additionally, we evaluated the potential impact of various environmental variables on the capture probability of O. flavescens in different strata. Detectability of this rodent was significantly increased in traps placed AGL than at ground level (GL). However, trap placement level did not influence seasonal variation in O. flavescens abundance. Furthermore, the increase in herbaceous cover at ground level positively influenced the probability of capturing O. flavescens in traps placed AGL. Traditional sampling designs relying solely on GL traps may perform well for studies focused on the population dynamics of O. flavescens. Conversely, in areas where herbaceous vegetation facilitates connectivity between the ground and shrub layers, adding AGL traps in the sampling strategy can guarantee better results for studies that need to capture a large number of O. flavescens individuals (i.e., seroprevalence studies or investigations on movements).

Very recently, an interesting phenomenon was described in the common vole; vole parents with similar locomotor ability produced significantly larger litters. Positive assortative mating is a tendency to prefer individuals with similar phenotypes. We tested whether this also applies to smell similarity. Odour preference was tested in a T-maze, where each female was presented with two male odours, i.e. shavings together with feces and urine from home boxes. After female preference was established, the female was either paired with a preferred male (chosen) or paired with a non-preferred male (opposite choice). For analysis of the relationship to odour preference, genotyping of major histocompatibility complex (MHC) Class II DRB was done using amplicon sequencing. In the set of 45 individuals from two populations, we recovered 38 nucleotide haplotypes (alleles). Similarity of alleles in parent pairs according to the indexes of Sørensen–Dice (S–D) and Jaccard were calculated. Values of these indexes in parental pairs with preferred males were significantly higher (more similar) than in not preferred. The number of offspring in parental pairs with preferred males were significantly higher than in not preferred males. However, there is no correlation between the mentioned indexes and the number of offspring. The relationship between the success of reproduction and alleles is not clear-cut, this may be influenced by the measure of similarity we used, or by something that we could not detect.

Mammalian carnivores exert direct and indirect effects on communities through top-down control and trophic ecology studies are helpful to understand the ecological processes behind these interactions. However, most diet studies reveal only local patterns. Large-scale biogeographic and anthropogenic drivers can also influence carnivore diet patterns. We investigated how latitude, altitude and human disturbance drive changes in Geoffroy’s cat (Leopardus geoffroyi) diets on a large geographical scale. Seventeen articles addressing the diet of Geoffroy’s cat were reviewed. We estimated the effects of drivers on three diet descriptor variables: diet composition, mean mammal-prey size and diet specialization. Our results uncover the primary use of prey around 300 g in body weight, such as Ctenomys and Cavia, through most of the geographic gradient. Only latitude and altitude caused replacement of prey species in diet composition. An increase in latitude led to higher diet specialization and larger prey selection, possibly guided by an increase in Lepus spp. consumption. Higher altitudes and an intensification of human disturbances decreased diet specialization and prey-size. Lastly, diet specialization increased with consumption of large prey. This further increases our understanding of Geoffroy’s cat broad adaptive capacity throughout South America.