Population genetics and ecological niche modeling of <i>Diglyphus albiscapus</i> (Hymenoptera: Eulophidae) in China

The effects of global climate change on the biocontrol of agricultural pests remain unclear. Understanding the geographical distribution and genetic differentiation of parasitoid wasps in past and current environments can help predict how the future environment will affect these wasps. Diglyphus albiscapus (Hymenoptera: Eulophidae) is a dominant parasitoid wasp of agromyzid leaf miners. Our study analyzed the intraspecific diversity, population structure, and historical population dynamics of D. albiscapus based on cytochrome c oxidase subunit I and internal transcribed spacer II genes. The current and future potential geographical distributions (PGD) of D. albiscapus in China were predicted using an ensemble model. Although the genetic diversity of D. albiscapus in China was relatively high, its genetic variation was relatively low. The fixation indices (FST) and gene flow (Nm) for the D. albiscapus population were 0.09823 and 2.29505, respectively, indicating that interpopulation gene exchange was adequate. The effective population size of D. albiscapus expanded approximately twofold during the early stadial of the last glacial period (MIS 4), and 3 populations expanded substantially. Currently, this species occurs mainly in northeast, northwest, and southern China. The PGD of D. albiscapus would be expected to spread outward from its current potential distribution range under global climate change. The predicted results of population genetics and PGD showed that anthropogenic activities may have promoted the spread of D. albiscapus, enhancing gene exchange within the species and reducing genetic differentiation. This study provided a reference for the conservation and application of D. albiscapus in the field.