The evolution of asymmetric genitalia in Coleoptera.
The evolution of asymmetry in male genitalia is a pervasive and recurrent phenomenon across almost the entire animal kingdom. Although in some taxa the asymmetry may be a response to the evolution of one-sided, male-above copulation from a more ancestral female-above condition, in other taxa, such as Mammalia and Coleoptera, this explanation appears insufficient. We carried out an informal assessment of genital asymmetry across the Coleoptera and found that male genital asymmetry is present in 43% of all beetle families, and at all within-family taxonomic levels. In the most diverse group, Cucujiformia, however, genital asymmetry is comparatively rare. We also reconstructed the phylogeny of the leiodid tribe Cholevini, and mapped aspects of genital asymmetry on the tree, revealing that endophallus sclerites, endophallus, median lobe and parameres are, in a nested fashion, increasingly unlikely to have evolved asymmetry. We interpret these results in the light of cryptic female choice versus sexually antagonistic coevolution and advocate further ways in which the phenomenon may be better understood.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
Endless Forms Group, Naturalis Biodiversity Center, Darwinweg 2, 2333CR Leiden, The Netherlands menno.schilthuizen@naturalis.nl.|Institute for Biology Leiden (IBL), Sylviusweg 72, 2333BE Leiden, The Netherlands.
Menno
0000-0001-6229-0347
M
Schilthuizen
Endless Forms Group, Naturalis Biodiversity Center, Darwinweg 2, 2333CR Leiden, The Netherlands.|Institute for Biology Leiden (IBL), Sylviusweg 72, 2333BE Leiden, The Netherlands.
Paulien
P
de Jong
Endless Forms Group, Naturalis Biodiversity Center, Darwinweg 2, 2333CR Leiden, The Netherlands.|Institute for Biology Leiden (IBL), Sylviusweg 72, 2333BE Leiden, The Netherlands.
Rick
R
van Beek
Endless Forms Group, Naturalis Biodiversity Center, Darwinweg 2, 2333CR Leiden, The Netherlands.|Institute for Biology Leiden (IBL), Sylviusweg 72, 2333BE Leiden, The Netherlands.
Tamara
T
Hoogenboom
Endless Forms Group, Naturalis Biodiversity Center, Darwinweg 2, 2333CR Leiden, The Netherlands.|Institute for Biology Leiden (IBL), Sylviusweg 72, 2333BE Leiden, The Netherlands.|Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085-1087, 1081 HV Amsterdam, The Netherlands.
Melanie Meijer Zu
MM
Schlochtern
D000818:Animals; D005075:Biological Evolution; D019521:Body Patterning; D001517:Coleoptera / Q000145:classification / Q000196:embryology* / Q000254:growth & development; D005837:Genitalia, Male / Q000196:embryology / Q000254:growth & development; D008297:Male; D010802:Phylogeny
beetles; chirality; penis; sexual selection