Data from: Evolutionary genomics of gypsy moth populations sampled along a latitudinal gradient

The European gypsy moth (Lymantria dispar L.) was first introduced to
Massachusetts in 1869 and within 150 years has spread throughout eastern
North America. This large-scale invasion across a heterogeneous landscape
allows examination of the genetic signatures of adaptation potentially
associated with rapid geographic spread. We tested the hypothesis that
spatially divergent natural selection has driven observed changes in three
developmental traits that were measured in a common garden for 165 adult
moths sampled from six populations across a latitudinal gradient covering
the entirety of the range. We generated genotype data for 91,468 single
nucleotide polymorphisms (SNPs) based on double digest restriction-site
associated DNA sequencing (ddRADseq) and used these data to discover
genome-wide associations for each trait, as well as to test for signatures
of selection on the discovered architectures. Genetic structure across the
introduced range of gypsy moth was small in magnitude (FST = 0.069), with
signatures of bottlenecks and spatial expansion apparent in the rare
portion of the allele frequency spectrum. Results from applications of
Bayesian sparse linear mixed models were consistent with the presumed
polygenic architectures of each trait. Further analyses were indicative of
spatially divergent natural selection acting on larval development time
and pupal mass, with the linkage disequilibrium like component of this
test acting as the main driver of observed patterns. The populations most
important for these signals were two range-edge populations established
less than 30 generations ago. We discuss the importance of rapid polygenic
adaptation to the ability of non-native species to invade novel
environments.