Genetic evidence for inter-population male – Biased dispersal of lesser rice field rat (Rattus losea) in Zhoushan Archipelago, China

Abstract

Dispersal is a fundamental life history trait that has profound effect on both the genetics and evolution of species, and sex-biased dispersal is pervasive in vertebrates. Lesser rice field rat (Rattus losea) belongs to the family Muridae and is one of the dominant rodents in Zhoushan archipelago, China. In this study, we genotyped 168 samples including 74 males and 94 females R. losea, live-captured from five neighboring islands during breeding seasons. Based on eight highly polymorphic autosomal microsatellite markers analyzed, we found that the island populations of R. losea maintained a large amount of genetic diversity, along with low to moderate levels of genetic variation, extensive gene flow and declining inbreeding. The Bayesian clustering divided the populations into three distinct genetic clusters. Analyses of sex-biased dispersal conducted over the total R. losea individuals presented that Fst, Fis, mAIc and r in females were higher than those in males, and conversely vAIc in females was lower than males, which all suggested a male-biased dispersal pattern in R. losea populations. This pattern of dispersal may be influenced by factors such as reducing mate competition and preventing inbreeding. In general, the study provides strong genetic evidence for male-biased dispersal of R. losea in Zhoushan archipelago, which has practical implications for understanding behavioral strategies for the adaptive evolution of island species in fine-scale populations and developing control methods for rodents in island ecosystems.