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. Recent research has uncovered considerable diversity and complexity in sex-biased dispersal patterns across species, although studies on snakes with secretive behaviors and low encounter rates remain limited. In this study, sex-biased dispersal in the Asian pitviper (Viridovipera stejnegeri) was investigated using microsatellite markers and a mark-recapture approach. The underlying factors contributing to sex-biased dispersal were also examined, with a focus on genetic structure, kinship patterns, and resource competition. Microsatellite 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 failing to support the resource competition hypothesis. 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. However, further investigation is needed to determine whether the local mate competition hypothesis applies. Overall, this study provides valuable insights into methodological approaches and data interpretation relevant to biodiversity conservation and management strategies.