The ability to recognize and differentiate between conspecifics and heterospecifics as well as their signals is critical for the coexistence of closely related species. In the genus Rattus, species are morphologically similar and multiple species often coexist. Here, we investigated the interspecific recognition and signal differentiation of two sympatric rat species, the brown rat (Rattus norvegicus, RN) and the Asian house rat (Rattus tanezumi, RT). In a two-way choice test, both RN and RT females showed a preference for conspecific male rats to heterospecific ones. RT females showed a significant preference for accessible urine of males of same species to those of other species, but not for the inaccessible urine. On the other hand, there were significant differences in the structural characteristics of the ultrasonic vocalization emitted by males of these two rat species. Sodium dodecyl sulphate‒polyacrylamide gel electrophoresis (SDS‒PAGE) and isoelectric focusing electrophoresis unveiled that major urinary proteins (MUPs) in voided urine were more highly expressed in RN males versus RT males. The interspecific differences of urinary volatile compounds were also discussed. In conclusion, female rats had the ability to distinguish between males of either species.
Human‐gray wolf conflict over livestock depredation and absence of mitigation measures is a key threat leading to the decline of wolf populations in Pakistan, where gray wolves are endangered. In this study, we collected data from January 2019 to September 2021, and human–wolf conflict and mitigation measures were investigated by interviews with 200 shepherds that were randomly selected from 43 different human settlements. We used binary logistic GLM models to predict landscape features related to gray wolf conflict patterns. Over the 3 years of the study, the gray wolf was responsible for 963 livestock losses and 244.50 million rupees (1,381,388.14 USD) in economic loss in summer, and 798 livestock losses along with 169.31 million rupees (956,608.1356 USD) economic loss in winter for the same 200 shepherds in Shigar valley. Our questionnaires revealed that shepherds hold negative attitudes toward the species when there is inadequate compensation by the several government department.
Global climate change has led to shifts in the distribution ranges of many terrestrial species, promoting their migration from lower altitudes or latitudes to higher ones. Meanwhile, successful invaders have developed genetic adaptations enabling the colonization of new environments. Over the past 40 years, Rattus tanezumi (RT) has expanded into northern China (Northwest and North China) from its southern origins. We studied the cold adaptation of RT and its potential for northward expansion by comparing it with sympatric Rattus norvegicus (RN), which is well adapted to cold regions. Through population genomic analysis, we revealed that the invading RT rats have split into three distinct populations: the North, Northwest, and Tibetan populations. The first two populations exhibited high genetic diversity, while the latter population showed remarkably low genetic diversity. These rats have developed various genetic adaptations to cold, arid, hypoxic, and high-UV conditions. Cold acclimation tests revealed divergent thermoregulation between RT and RN. Specifically, RT exhibited higher brown adipose tissue activity and metabolic rates than did RN. Transcriptome analysis highlighted changes in genes regulating triglyceride catabolic processes in RT, including Apoa1 and Apoa4, which were upregulated, under selection and associated with local adaptation. In contrast, RN showed changes in carbohydrate metabolism genes. Despite the cold adaptation of RT, we observed genotypic and phenotypic constraints that may limit its ability to cope with severe low temperatures farther north. Consequently, it is less likely that RT rats will invade and overlap with RN rats in farther northern regions.
Knowledge of the mechanisms of species coexistence is crucial for biodiversity conservation. The tufted deer (Elaphodus cephalophus), alpine musk deer (Moschus chrysogaster), and Chinese serow (Capricornis milneedwardsii) are all found in alpine ecosystems in Tibet, China. To investigate how these sympatric species achieve stable coexistence, we compared species distribution models and diurnal activity rhythms to analyze their spatial and temporal niche characteristics based on data collected from 186 camera traps set in Changdu prefecture. The results indicate he following: (1) In Changdu, the total area of suitable habitats for tufted deer, alpine musk deer and Chinese serow are 14,968 km2, 41,909 km2, and 36,954 km2, respectively. These areas represent approximately 13.62%, 38.14%, and 33.63% of the study area, respectively. (2) The total overlapping area of suitable habitats between tufted deer and alpine musk deer is 5102 km2. The total overlapping area of suitable habitats between tufted deer and Chinese serow is 6483 km2. Additionally, the total overlapping area of suitable habitats between alpine musk deer and Chinese serow amounts to 26,869 km2. (3) The overlap index for daily activity rhythms between tufted deer and alpine musk deer is 0.88—this difference is statistically significant (p < 0.001). Similarly, the overlap index for daily activity rhythms between tufted deer and Chinese serow is 0.82—also significantly different (p < 0.001). Lastly, the overlap index for daily activity rhythms between alpine musk deer and Chinese serow is 0.76—again showing a significant difference (p < 0.001). The results provide valuable insight into conservation strategies aimed at preserving populations and habitats of tufted deer, alpine musk deer, and Chinese serow while contributing to a deeper understanding of resource partitioning mechanisms as well as population dynamics among coexisting species.