Multiple lines of evidence for sex-biased dispersal in the nocturnal pitviper Viridovipera stejnegeri

Sex-biased dispersal, a widespread phenomenon in the animal kingdom, plays a crucial role in shaping genetic structure, optimizing population dynamics, and sustaining reproductive success. However, recent research has uncovered considerable diversity and complexity in sex-biased dispersal across species. Especially for snakes with secretive behaviors and low encounter rates, research is limited. In this study, we investigated sex-biased dispersal in the Asian pitviper (Viridovipera stejnegeri) using microsatellite genetic markers and a mark-recapture approach. We also explored the underlying factors contributing to sex-biased dispersal based on genetic structure, kinship patterns, and resource competition. Microsatellite marker analyses revealed an overall pattern of female-biased dispersal in V. stejnegeri, although certain populations exhibited male-biased dispersal. Notably, these variations in dispersal patterns among populations were not associated with genetic differentiation. The contrasting results between microsatellite data and mark-recapture methods highlighted the limitations of using mark-recapture alone to investigate sex-biased dispersal in snakes. Analyses indicated no significant differences in intrasexual and intersexual resource competition pressures, thus the resource competition hypothesis cannot be proven, and further research is needed. Kinship analysis showed no significant clustering of consanguineous individuals within subpopulations; rather, individuals dispersed into neighboring subpopulations through sex-biased dispersal, effectively reducing the risk of inbreeding and supporting the inbreeding avoidance hypothesis. Further investigation is needed to determine whether the local mate competition hypothesis applies. This study provides valuable insights into methodological approaches and data interpretation relevant to biodiversity conservation and management strategies.