Genotyping-by-sequencing supports a genetic basis for wing reduction in an alpine New Zealand stonefly

Abstract

Wing polymorphism is a prominent feature of numerous insect groups, but the genomic basis for this diversity remains poorly understood. Wing reduction is a commonly observed trait in many species of stonefies, particularly in cold or alpine environments. The widespread New Zealand stonefy Zelandoperla fenestrata species group (Z. fenestrata, Z. tillyardi, Z. pennulata) contains populations ranging from fully winged (macropterous) to vestigial-winged (micropterous), with the latter phenotype typically associated with high altitudes. The presence of fightless forms on numerous mountain ranges, separated by lowland fully winged populations, suggests wing reduction has occurred multiple times. We use Genotyping by Sequencing (GBS) to test for genetic diferentiation between fully winged (n=62) and vestigial-winged (n=34) individuals, sampled from a sympatric population of distinct wing morphotypes, to test for a genetic basis for wing morphology. While we found no population genetic diferentiation between these two morphotypes across 6,843 SNP loci, we did detect several outlier loci that strongly diferentiated morphotypes across independent tests. These fndings indicate that small regions of the genome are likely to be highly diferentiated between morphotypes, suggesting a genetic basis for wing reduction. Our results provide a clear basis for ongoing genomic analysis to elucidate critical regulatory pathways for wing development in Pterygota.