Widespread species that exhibit both high gene flow and the capacity to occupy heterogeneous environments make excellent models for examining local selection processes along environmental gradients. Here we evaluate the influence of temperature and landscape variables on genetic connectivity and signatures of local adaptation in Phaulacridium vittatum, a widespread agricultural pest grasshopper, endemic to Australia. With sampling across a 900 km latitudinal gradient, we genotyped 185 P. vittatum from 19 sites at 11,408 single nucleotide polymorphisms (SNPs) using ddRAD sequencing. Despite high gene flow across sites (pairwise Fst = 0.0003-0.08), landscape genetic resistance modelling identified a positive non-linear effect of mean annual temperature on genetic connectivity. Urban areas and water bodies had a greater influence on genetic distance among sites than pasture, agricultural areas, and forest. Together, Fst outlier tests and Environmental Association Analysis (EAA) detected 242 unique SNPs under putative selection, with the highest numbers associated with latitude, mean annual temperature, and body size. A combination of landscape genetic connectivity analysis together with EAA identified mean annual temperature as a key driver of both neutral gene flow and environmental selection processes. Gene annotation of putatively adaptive SNPs matched with gene functions for olfaction, metabolic detoxification and ultra-violet light shielding. Our results imply that this widespread agricultural pest has the potential to spread and adapt under shifting temperature regimes and land cover change.

3257_snps_PvittFiltered dataset PED format consisting of 3,257 SNPs genotyped in 185 individuals of Phaulacridium vittatum.3257_snps_PvittDatafile (map format) consisting names of 3257 loci11408_snps_PvittFiltered dataset consisting of 11,408 SNPs genotyped in 185 individuals used for adaptive genetic analysis11408_snps_PvittMap file containing 11,408 SNP loci name.Model_selection_LandcoverR script to perform model selectionalpha_gamma_valuesDatafile consisting values of of alpha and gamma. Required to generate resistance surfaces.Landcover_150m_resRe-classified landcover raster file used to generate multiple resistance surfaces.BIO1_Mean_annual_tempAnnual mean temperature raster file used to generate multiple resistance surfacesMorphology_185_ind_PvittMorphological data of 185 individuals used to test morph-environment association in LFMM.