Lock-and-key structural isolation between sibling Drosophila species

Yoshitaka Kamimura, Hiroyuki Mitsumoto

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


Drosophila santomea Lachaise & Harry, which is endemic to the African island of São Tomé, and its sibling D.yakuba Burla comprise a new model system of speciation. They are morphologically distinguishable only by slight differences in the male genitalia and body coloration. As a previously undescribed difference, the aedeagus of D.yakuba bears a pair of stout spines (the ventral branches of the basal processes (VB)), instead of the paired humps found in D.santomea. Here, we show that this difference works as a lock-and-key isolating mechanism between the siblings. During conspecific copulation, D.yakuba females receive the spines in a pair of pocket-shaped structures, which are protected by hardened plates, in the genitalia. The females of D.santomea, which lack such pockets, are wounded by the spines of the VB when mated with D.yakuba males. This genital mismatching resulted in leakage of the ejaculate, making 80% of the matings infertile and causing a prolonged struggle to separate pairs glued together by the ejaculate.

Original languageEnglish
Pages (from-to)197-201
Number of pages5
JournalEntomological Science
Issue number2
Publication statusPublished - 2012 Apr


  • Cost of mating
  • Evolution of genitalia
  • Infertile mating
  • Reproductive isolation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Insect Science


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