Data from: Recent range expansion and genomic admixture in a kleptoparasitic spider, Argyrodes lanyuensis: A case of adaptive introgression on isolated small island of the Taiwan-Philippine transition zone?

Adaptive introgression involves the acquisition of advantageous genetic
variants through hybridization, which subsequently are favored by natural
selection due to their association with beneficial traits. These
post-introgression adaptive alleles inherited from related species may
allow the hybrid lineage to adapt to new environmental changes or exploit
novel ecological niches. Here, we analyzed speciation patterns of the
kleptoparasitic spider Argyrodes lanyuensis through genomic analyses and
tested for genetic evidence of adaptive introgression at the
Taiwan-Philippines transition zone. Using highly polymorphic SNPs, our
study demonstrated that speciation occurred when the Hualien (on Taiwan
Island) and Philippine (including the Orchid Island) lineages separated
during the early to mid-Pleistocene. The best colonization model suggested
by Approximate Bayesian Computation and Random Forests supported an
inference of a bottleneck during speciation, an interpretation reinforced
by observation of lower FST values and reduced genetic diversity of the
Philippine+Orchid Island lineage. We found the highest support for the
occurrence of introgression on the youngest island (Green Island) of the
Taiwan-Philippines transition zone based on ABBA-BABA test. Additionally,
we have identified a putative adaptive locus under balancing selection on
Green Island, suggesting evolution by adaptive introgression in a
newly-formed niche (or novel geographical context). Our study highlights a
possible rare case of introgression at the Taiwan-Philippines transition
zone under balancing selection, that could be an evolutionary response to
a unique climatological zone lying between the tropical climate of the
Philippines and the subtropical climate of Hualien, Taiwan.