Lin Zhang

Ascodipteron bat flies are specialized parasites of bats, but their diversity and parasite ecology in China remain poorly understood. We surveyed hipposiderid bats at ten localities in Yunnan Province, China, combining morphological identification, mitochondrial cytochrome c oxidase subunit I (COI) barcoding, and ecological analyses. Among 226 bats, 58 were infested; 72 neosomic females were collected, and 14 representative specimens were sequenced. Morphology, COI genetic distances, Assemble Species by Automatic Partitioning (ASAP), and maximum-likelihood phylogenetic analysis supported three taxa: A. phyllorhinae, A. sanmingense, and an undescribed Ascodipteron sp. Within-taxon COI distances were 0.199–0.512%, whereas between-taxon distances were 6.303–12.118%. Overall prevalence was 25.66%, and prevalence and mean parasite abundance varied among host species. Evidence for host-species differences in parasitism depended strongly on the absence of infestation in Hipposideros gentilis. Estimated associations of body condition with infestation occurrence and parasite abundance were positive but uncertain, and no clear associations were detected for the site-level environmental variables examined. These findings expand current knowledge of Ascodipteron diversity and host-associated parasitism in Yunnan and provide an integrative basis for further studies of species identification, host use, and parasite ecology in this genus.

Understanding adaptive evolution has long fascinated evolutionary biologists. Adaptive phenotypic divergence is often driven by modifications to protein-coding sequences. The Rhinolophus macrotis group exhibits relatively lower echolocation frequencies relative to body size compared with other rhinolophids, implying distinct evolutionary trajectories. Transcriptomes bridge genotypes and phenotypes. Here, we sequenced brain, liver and cochlea transcriptomes from one individual per species representing five taxa of the macrotis group. We performed comparative transcriptomic analyses and detected signals of positive selection. Seven hearing-related genes (CRYM, FOXM1, MAP6, PYCARD, SLC35A2, WRB and SPRY2) were under positive selection. Unexpectedly, we also identified five vision-associated positively selected genes (ARRDC3, LZTFL1, RAB8A, IGFBPL1 and TRNT1) in taxa with relatively lower echolocation frequencies within the macrotis group, indicating selection on sensory genes. Furthermore, candidate positively selected genes were significantly enriched in metabolism-related GO terms such as catalytic and oxidoreductase activity. Our study offers valuable transcriptomic resources for unraveling adaptive genetic mechanisms in horseshoe bats.

Understanding the adaptive evolution of species has long interested evolutionary biologists. Adaptive phenotypes can result from changes in protein-coding sequences that affect protein structure and function. The Rhinolophus macrotis group as a specific group has low echolocation frequency relative to body size compared with other rhinolophids, suggesting a special evolutionary process of this group. Transcription bridges genetic information and phenotypes. Here, we sequenced transcriptomes of the brain, liver, and cochlea for five species of the macrotis group and its closely related species, R. pusillus, to explore the molecular basis of the adaptation in the macrotis group at the sequence level. Strong and significant positive selection signals for species within the macrotis group was detected in seven genes (CRYM, FOXM1, MAP6, PYCARD, SLC35A2, WRB and SPRY2) linked to hearing. Unexpectedly, we also detected five PSGs (ARRDC3, LZTFL1, RAB8A, IGFBPL1 and TRNT1) linked to vision in species with relatively low frequencies. These results suggested that natural selection has led to the positive selection of some sensory-related genes. Furthermore, PSGs identified in the macrotis group significantly enriched in GO categories related to metabolism (e.g. catalytic activity and oxidoreductase activity), which provided evidence to parse the genetic adaptations of the species with low frequencies within the macrotis group. This is the first attempt to detect genome-wide sequence evolution across the macrotis group and our study provided valuable resources for studying the genetic mechanisms of rhinolophids adaptation.

Determining the evolutionary history and population drivers, such as past large-scale climatic oscillations, stochastic processes and ecological adaptations, represents one of the aims of evolutionary biology. Hipposideros larvatus is a common bat species in Southern China, including Hainan Island. We examined genetic variation in H. larvatus using mitochondrial DNA and nuclear microsatellites. We found a population structure on both markers with a geographic pattern that corresponds well with the structure on mainland China and Hainan Island. To understand the contributions of geography, the environment and colonization history to the observed population structure, we tested isolation by distance (IBD), isolation by adaptation (IBA) and isolation by colonization (IBC) using serial Mantel tests and RDA analysis. The results showed significant impacts of IBD, IBA and IBC on neutral genetic variation, suggesting that genetic variation in H. larvatus is greatly affected by neutral processes, environmental adaptation and colonization history. This study enriches our understanding of the complex evolutionary forces that shape the distribution of genetic variation in bats.

Heat stress (HS) leads to substantial economic loss of dairy industry each year. The negative effect of HS in dairy cows is becoming one of the more urgent issue due to accelerating side-effects of global warming. Various genes are involved in HS response but the information about the role of noncoding RNAs, especially circular RNAs (circRNAs) is largely unknown. In our study, we aimed to investigate the different expression profile of circRNAs between HS and Non-heat-stressed condition (NC) of Chinese Holstein cow’s mammary gland. CircRNAs were identified using RNA sequencing and bioinformatics analysis. In total, 37405 circRNAs were detected and 95 were differentially expressed (DE), including 15 downregulated and 80 upregulated circRNAs in HS group compared to NC. Eight circRNAs were randomly selected to verify the RNA sequencing result. Further, Sanger sequencing validated the backsplicing site of the eight circRNAs. Moreover, results obtained from the Quantitative real time PCR (qRT-PCR) showed consistent expression trend with that of RNA sequencing. GO annotation and KEGG analysis suggested that these DE circRNAs probably involved in the energy metabolic regulation. Furthermore, we constructed ceRNA network and the result indicated that these DE circRNAs could regulate lactation through IGF1 and PRL signaling pathway.