The genetic architecture of ecological adaptation: Intraspecific variation in host plant use by the lepidopteran crop pest Chloridea virescens

Authors: OPPENHEIM, SARA - American Museum Of Natural History; GOULD, FRED - North Carolina State University; Hopper, Keith

Submitted to: Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2017
Publication Date: 12/14/2017
Citation: Oppenheim, S.J., Gould, F.L., Hopper, K.R. 2017. The genetic architecture of ecological adaptation: Intraspecific variation in host plant use by the lepidopteran crop pest Chloridea virescens. Heredity. published online.

Interpretive Summary: Genetic adaptation of insect pests to crops may lead to new problems in agriculture. Whether adaptation will occur depends on the genes involved and their interactions. We mapped genetic regions affecting the adaptation to a new host plant species by larvae of species in the genus Chloridea, a group of noctuid moths that contains important crop pests. We found that the numbers and interactions among genes were similar within as well as between moth species. Our results suggest that incremental adaptation to a new host plant species could follow many different genetic routes, so that a gradual shift onto a new host would be possible in the field.

Technical Abstract: Intra- and interspecific variation in ecologically important traits can be thought of as a continuum, with intraspecific variation serving as the raw material upon which natural selection acts. Whether such variation is typically controlled by the same genes within and between species is an open question in evolutionary biology, and few comparisons have been made at the genetic level. Determining whether parallel adaptations rely on the same genetic mechanisms is largely a question of genetic architecture, as the number, distribution, and effect size of the genes involved will determine the ways in which a trait can respond to selection. We mapped quantitative trait loci (QTL) to study the genetic architecture of host plant use at both the inter- and intraspecific level in the genus Chloridea, a group of noctuid moths that contains many damaging crop pests. We found that the underlying genetic architectures of intra- and interspecific variation are very similar, involving a large number of interchangeable QTL with incremental effects on the ability to use the host plant Physalis angulata. We conclude that incremental adaptation to P. angulata could proceed along many different genetic routes, suggesting that a gradual shift by C. virescens onto this novel host would be possible in the field.