Drosophila pachea asymmetric lobes are part of a grasping device and stabilize one-sided mating

Background Multiple animal species exhibit morphological asymmetries in male genitalia. In insects, left-right genital asymmetries evolved many times independently and have been proposed to appear in response to changes in mating position. However, little is known about the relationship between mati...

Full description

Saved in:
Bibliographic Details
Published in:BMC evolutionary biology Vol. 16; no. 1; p. 176
Main Authors: Rhebergen, Flor T., Courtier-Orgogozo, Virginie, Dumont, Julien, Schilthuizen, Menno, Lang, Michael
Format: Journal Article
Language:English
Published: London BioMed Central 01.09.2016
BioMed Central Ltd
Subjects:
Abdomen - anatomy & histology
Animal biology
Animal Systematics/Taxonomy/Biogeography
Animals
Biological Evolution
Biomechanical Phenomena
Biomedical and Life Sciences
Copulation - physiology
Courtship of animals
Drosophila
Drosophila - anatomy & histology
Drosophila - physiology
Drosophila - ultrastructure
Entomology
Evolutionary Biology
Female
Genetics and Population Dynamics
Genitalia, Female - anatomy & histology
Genitalia, Female - ultrastructure
Genitalia, Male - anatomy & histology
Genitalia, Male - ultrastructure
Invertebrate Zoology
Life Sciences
Male
Morphology (Animals)
Mutation - genetics
Physiological aspects
Reproduction
Reproductive Biology
Research Article
Sexual Behavior, Animal - physiology
Sexual reproduction
Time Factors
Mating position
Genitalia
Left-right asymmetry
Epandrial lobe
Micro-surgery
Laser ablation
species group
Drosophila pachea
Nannoptera species group
ISSN:1471-2148, 1471-2148
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Background Multiple animal species exhibit morphological asymmetries in male genitalia. In insects, left-right genital asymmetries evolved many times independently and have been proposed to appear in response to changes in mating position. However, little is known about the relationship between mating position and the interaction of male and female genitalia during mating, and functional analyses of asymmetric morphologies in genitalia are virtually non-existent. We investigated the relationship between mating position, asymmetric genital morphology and genital coupling in the fruit fly Drosophila pachea , in which males possess an asymmetric pair of external genital lobes and mate in an unusual right-sided position on top of the female. Results We examined D. pachea copulation by video recording and by scanning electron microscopy of genital complexes. We observed that the interlocking of male and female genital organs in D. pachea is remarkably different from genital coupling in the well-studied D. melanogaster . In D. pachea , the female oviscapt valves are asymmetrically twisted during copulation. The male’s asymmetric lobes tightly grasp the female’s abdomen in an asymmetric ‘locking’ position, with the left and right lobes contacting different female structures. The male anal plates, which grasp the female genitalia in D. melanogaster , do not contact the female in D. pachea . Experimental lobe amputation by micro-surgery and laser-ablation of lobe bristles led to aberrant coupling of genitalia and variable mating positions, in which the male was tilted towards the right side of the female. Conclusion We describe, for the first time, how the mating position depends on coupling of male and female genitalia in a species with asymmetric genitalia and one-sided mating position. Our results show that D. pachea asymmetric epandrial lobes do not act as a compensatory mechanism for the change from symmetric to one-sided mating position that occurred during evolution of D. pachea ’s ancestors, but as holding devices with distinct specialized functions on the left and right sides.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
PMCID: PMC5009675
ISSN:1471-2148
1471-2148
DOI:10.1186/s12862-016-0747-4