Genetics of incipient speciation in Drosophila mojavensis: II. Host plants and mating status influence cuticular hydrocarbon QTL expression and GxE interactions

WJ Etges, C Cardoso de Oliveira, Michael Gordon Ritchie, MAF Noor

Research output: Contribution to journalArticlepeer-review

56 Citations (Scopus)

Abstract

We performed a quantitative trait locus (QTL) analysis of epicuticular hydrocarbon variation in 1650 F-2 males from crosses of Baja California and mainland Mexico populations of Drosophila mojavensis cultured on two major host cacti. Principal component (PC) analysis revealed five PCs that accounted for 82% of the total epicuticular hydrocarbon variation. Courtship trials with mainland females were used to characterize hydrocarbon profiles of mated and unmated F-2 males, and logistic regression analysis showed that cactus substrates, two PCs, and a PC by cactus interaction were associated with mating success. Multiple QTLs were detected for each hydrocarbon PC and seven G x E (cactus) interactions were uncovered for the X, second, and fourth chromosomes. Males from the courtship trials and virgins were used, so "exposure to females" was included as a factor in QTL analyses. "Exposed" males expressed significantly different hydrocarbon profiles than virgins for most QTLs, particularly for the two PCs associated with mating success. Ten QTLs showed G x E (exposure) interactions with most resulting from mainland genotypes expressing altered hydrocarbon amounts when exposed to females compared to Baja genotypes. Many cactus x exposure interaction terms detected across QTL and all PCs confirmed that organ pipe-reared males expressed significantly lower hydrocarbon amounts when exposed to females than when reared on agria cactus. Epicuticular hydrocarbon variation in D. mojavensis is therefore a multigenic trait with some epistasis, multiple QTLs exhibited pleiotropy, correlated groups of hydrocarbons and cactus substrates determined courtship success, and males altered their hydrocarbon profiles in response to females.

Original languageEnglish
Pages (from-to)1712-1730
Number of pages19
JournalEvolution
Volume63
Issue number7
DOIs
Publication statusPublished - Jul 2009

Keywords

  • Plant-insect interaction
  • pleiotropy
  • quantitative genetics
  • reproductive isolation
  • speciation
  • QUANTITATIVE TRAIT LOCI
  • MALE COURTSHIP SONG
  • CACTOPHILIC DROSOPHILA
  • REPRODUCTIVE ISOLATION
  • PREMATING ISOLATION
  • ISOLATED POPULATIONS
  • NATURAL-SELECTION
  • SEXUAL ISOLATION
  • PEA APHIDS
  • EPICUTICULAR HYDROCARBONS

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