Interspecific differences in the abdominal hair and mid-tibial traits are likely determined by a single locus in Ostrinia moths (Lepidoptera: Crambidae)

Abstract

Ostrinia Hübner (Lepidoptera: Crambidae) is a moth genus that includes major agricultural pests and has been used as a model for studies such as chemical ecology and reproductive manipulation by its symbionts. The presence or absence of abdominal hair tufts and the morphology of the mid tibiae (small, medium, or large) in males both represent major interspecific and intraspecific differences in this genus. In this study, we generated hybrids between two Ostrinia species (O. furnacalis and O. scapulalis) with different abdominal hair and mid-tibial phenotypes to explore their hereditary modes. The ratios of abdominal hair phenotypes in F2 and backcrossed individuals indicated that a single dominant locus on an autosome determines the presence of abdominal tufts in males. After 23 rounds of backcrossing to O. furnacalis (lacking abdominal tufts), where only individuals with abdominal tufts were selected as male parents in each generation, males with abdominal tufts also exhibited enlarged, grooved mid tibiae, whereas those without abdominal tufts did not. According to these results, the two traits are most likely governed by the same locus, or tightly linked genomic regions, in Ostrinia moths. This study is the first to clarify the genetic association between abdominal hair and mid-tibial traits, thus providing insights into understanding the evolution of a male-specific novelty in the genus.