Association Analysis Between Sexual Dimorphism And Intestinal Microbiome In Hipposideros Pratti

Gut microbes are closely related to the physiology and health of their hosts.The host genetic background affects the composition and structure of gut microbes,while the gut microbiome can reflect the phylogenetic relationships of the host.The fleshy shields in the noseleaf structure of Hipposideros pratti show a clear sexual dimorphism,with adult males growing exaggerated fleshy shields,which usually imply higher energy payoffs and reduced body flexibility,the significance of which is unclear.In this study,we investigated the association between shield size and gut microbiome by analyzing the gut microbiome of male H.pratti with different shield sizes using highthroughput sequencing,hoping to provide a relevant basis for revealing the evolutionary mechanism of sexual dimorphism of Pratt’s roundleaf bats’ shields.The main findings of this study are as follows:(1)Correlation analysis between microbial species abundance in different gut regions and host shield size in male Pratt’s roundleaf bats showed that the amount of Ureaplasma,which can negatively affect sperm quality,decreased in the large intestine with increasing shield size.The content of probiotic bacteria(Lachnospiraceae＿NK4A136＿group,Ruminococcus＿1,Bacteroides,etc.)in the small intestine increased with the increase of shield area,which could promote lipid catabolism,maintain homeostasis of the flora structure and characterize good nutritional status of the host.These microbes have an important role in the maintenance of sperm quality and normal gut function in H.pratti.(2)Among the functional entries of microbial genes that were significantly positively correlated with shield area,the products of caffeine metabolic pathway helped bats to efficiently perform flight and dormancy activities.In addition,the pathways associated with sex hormone synthesis also increased with increasing shield area,which is more conducive to healthy development of the reproductive system in H.pratti.(3)Comparison of the gut microbial molecular ecological network showed that the overall gut microbial network of bats with larger shields is more stable and more tightly connected internally.In summary,these results reflect that male H.pratti with large shields may have significant advantages over bats with small shields in terms of sperm quality,gut function,and adaptation to flight and dormancy activities,suggesting that shield size may play an important role in sexual selection,and the results provide a reference for future studies on sexual dimorphism in Pratt’s roundleaf bat.