Influence of host plant, geography and pheromone strain on genomic differentiation in sympatric populations of Ostrinia nubilalis

Abstract

Patterns of mating for the European corn borer (Ostrinia nubilalis) moth depend in part on variation in sex‐pheromone blend. The ratio of (E)‐11‐ and (Z)‐11‐tetradecenyl acetate (E11‐ and Z11‐14:OAc) in the pheromone blend that females produce and males respond to differs between strains of O. nubilalis. Populations also vary in female oviposition preference for and larval performance on maize (C4) and nonmaize (C3) host plants. The relative contributions of sexual and ecological trait variation to the genetic structure of O. nubilalis remains unknown. Host‐plant use (13C/14C ratios) and genetic differentiation were estimated among sympatric E and Z pheromone strain O. nubilalis males collected in sex‐pheromone baited traps at 12 locations in Pennsylvania and New York between 2007 and 2010. Among genotypes at 65 single nucleotide polymorphism marker loci, variance at a position in the pheromone gland fatty acyl‐reductase (pgfar) gene at the locus responsible for determining female pheromone ratio (Pher) explained 64% of the total genetic differentiation between males attracted to different pheromones (male response, Resp), providing evidence of sexual inter‐selection at these unlinked loci. Principal coordinate, Bayesian clustering, and distance‐based redundancy analysis (dbRDA) demonstrate that host plant history or geography does not significantly contribute to population variation or differentiation among males. In contrast, these analyses indicate that pheromone response and pgfar‐defined strain contribute significantly to population genetic differentiation. This study suggests that behavioural divergence probably plays a larger role in driving genetic variation compared to host plant‐defined ecological adaptation.

Influence of voltine ecotype and geographic distance on genetic and haplotype variation in the Asian corn borer

“…This and prior work (Levy et al, 2015) also suggest that voltinism traits may be influenced by loci physically unlinked to Pdd. Furthermore, combinations or interactions of ecological, phenological, and major and minor contributing genetic factors may influence the degree of divergence within Ostrinia species at the population scale (Coates et al, 2019;Kozak et al, 2017;Levy et al, 2015). The prediction of significant haplotype variation between univoltine and bivoltine O. furnacalis in this study could be attributed to a byproduct of ecologically influenced phenology differences, degree of adult mating period asynchrony and resulting allochronic reproduction, and subsequent disparity in female mitochondrial haplotype exchange.…”

bric à brac controls sex pheromone choice by male European corn borer moths

“…Asymmetric male preference for female pheromones in O. nubilalis is thought to contribute to a pattern of positive assortative mating 25 , 26 , which theory predicts will lead to two types of non-random genetic correlations at alleles controlling signals (here, the female pheromone blend) and preferences (here, the male preference for the female pheromone) 27 . First, alleles for signals will associate non-randomly with alleles for preferences, and second, a deficit of heterozygotes will occur at loci determining assortment.…”

Genomic Basis of Circannual Rhythm in the European Corn Borer Moth

“…We thank Dan Hahn, Tim Sackton, and two anonymous reviewers for helpful comments on this paper. We also thank our funding sources: National Science Foundation pheromone traps [112] and have been consistently phenotyped as short PDD over a 15-year period [113,114]. Field collected individuals were Z pheromone strain (homozygous for the Z locus at pgfar [82]).…”