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Lock‐and‐key structural isolation between sibling Drosophila species
Author(s) -
KAMIMURA Yoshitaka,
MITSUMOTO Hiroyuki
Publication year - 2012
Publication title -
entomological science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 28
eISSN - 1479-8298
pISSN - 1343-8786
DOI - 10.1111/j.1479-8298.2011.00490.x
Subject(s) - aedeagus , biology , zoology , male genitalia , reproductive isolation , sibling , key (lock) , anatomy , sibling species , evolutionary biology , taxonomy (biology) , ecology , demography , psychology , population , developmental psychology , sociology
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.