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A time‐sequence functional analysis of mating behaviour and genital coupling in Drosophila : role of cryptic female choice and male sex‐drive in the evolution of male genitalia
Author(s) -
JAGADEESHAN S.,
SINGH R. S.
Publication year - 2006
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2006.01099.x
Subject(s) - biology , sexual selection , mating , evolutionary biology , courtship , mate choice , zoology , female sperm storage , sex organ , sperm competition , genetics
Male genitalia in Drosophila exemplify strikingly rapid and divergent evolution, whereas female genitalia are relatively invariable. Whereas precopulatory and post‐copulatory sexual selection has been invoked to explain this trend, the functional significance of genital structures during copulation remains obscure. We used time‐sequence analysis to study the functional significance of external genitalic structures during the course of copulation, between D. melanogaster and D. simulans . This functional analysis has provided new information that reveals the importance of male‐driven copulatory mechanics and strategies in the rapid diversification of genitalia. The posterior process, which is a recently evolved sexual character and present only in males of the melanogaster clade, plays a crucial role in mounting as well as in genital coupling. Whereas there is ample evidence for precopulatory and/or post‐copulatory female choice, we show here that during copulation there is little or no physical female choice, consequently, males determine copulation duration. We also found subtle differences in copulatory mechanics between very closely related species. We propose that variation in male usage of novel genitalic structures and shifts in copulatory behaviour have played an important role in the diversification of genitalia in species of the Drosophila subgroup.