Sexual Selection Within the Female Genitalia in Lepidoptera

Postcopulatory sexual selection may favour mechanisms to reduce sperm competition, like physical sperm removal by males. To investigate the origin of sperm removal, I studied the reproductive behaviour and mechanisms of sperm competition in the only living member of the oldest damselfly family,Hemiphlebia mirabilis, one species that was considered extinct in the 1980s. This species displays scramble competition behaviour. Males search for females with short flights and both sexes exhibit a conspicuous “abdominal flicking”. This behaviour is used by males during an elaborate precopulatory courtship, unique among Odonata. Females use a similar display to reject male attempts to form tandem, but eventually signal receptivity by a particular body position. Males immobilise females during courtship using their legs, which, contrarily to other damselflies, never autotomise. Copulation is short (range 4.1–18.7 min), and occurs in two sequential stages. In the first stage, males remove part of the stored sperm, and inseminate during the second stage, at the end of mating. The male genital ligula matches the size and form of female genitalia, and ends by two horns covered by back-oriented spines. The volume of sperm in females before copulation was 2.7 times larger than the volume stored in females whose copulation was interrupted at the end of stage I, indicative of a significant sperm removal. These results point out that sperm removal is an old character in the evolution of odonates, possibly dating back to the Permian.

Download Full-text

Sperm removal during copulation confirmed in the oldest extant damselfly, Hemiphlebia mirabilis

10.7287/peerj.preprints.1810 ◽

2016 ◽

Author(s):

Adolfo Cordero-Rivera

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Short Range ◽

Body Position ◽

Reproductive Behaviour ◽

Scramble Competition ◽

Stage I ◽

Female Genitalia ◽

Second Stage ◽

Two Stages

Postcopulatory sexual selection may favour mechanisms to reduce sperm competition, like physical sperm removal by males. To investigate the origin of sperm removal, I studied the reproductive behaviour and mechanisms of sperm competition in the only living member of the oldest damselfly family, Hemiphlebia mirabilis, one species that was considered extinct in the 1980s. This species displays scramble competition behaviour, whose males search for females with short flights and both sexes exhibit a conspicuous “abdominal flicking”. This behaviour is used by males during an elaborate precopulatory courtship, unique among the Odonata. Females use a similar display to reject male attempts to form tandem, but eventually signal receptivity by a particular body position. Males immobilise females during courtship using their legs, which, contrarily to other damselflies, never autotomize. Copulation is short (range 4.1-18.7 min), and has two stages. In the first stage, males remove part of the stored sperm, and inseminate during the second stage, at the end of mating. The examination of genitalia indicates that males have two horns covered by back-oriented spines, which match the size and form of female genitalia. The volume of sperm in females after copulation was 2.8 times larger than the volume stored in females whose copulation was interrupted at the end of stage I, indicative of a significant sperm removal. These results point out that sperm removal is an old character in the evolution of odonates, probably dating back to the Permian.

Download Full-text

Sperm removal during copulation confirmed in the oldest extant damselfly, Hemiphlebia mirabilis

10.7287/peerj.preprints.1810v1 ◽

2016 ◽

Author(s):

Adolfo Cordero-Rivera

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Short Range ◽

Body Position ◽

Reproductive Behaviour ◽

Scramble Competition ◽

Stage I ◽

Female Genitalia ◽

Second Stage ◽

Two Stages

Postcopulatory sexual selection may favour mechanisms to reduce sperm competition, like physical sperm removal by males. To investigate the origin of sperm removal, I studied the reproductive behaviour and mechanisms of sperm competition in the only living member of the oldest damselfly family, Hemiphlebia mirabilis, one species that was considered extinct in the 1980s. This species displays scramble competition behaviour, whose males search for females with short flights and both sexes exhibit a conspicuous “abdominal flicking”. This behaviour is used by males during an elaborate precopulatory courtship, unique among the Odonata. Females use a similar display to reject male attempts to form tandem, but eventually signal receptivity by a particular body position. Males immobilise females during courtship using their legs, which, contrarily to other damselflies, never autotomize. Copulation is short (range 4.1-18.7 min), and has two stages. In the first stage, males remove part of the stored sperm, and inseminate during the second stage, at the end of mating. The examination of genitalia indicates that males have two horns covered by back-oriented spines, which match the size and form of female genitalia. The volume of sperm in females after copulation was 2.8 times larger than the volume stored in females whose copulation was interrupted at the end of stage I, indicative of a significant sperm removal. These results point out that sperm removal is an old character in the evolution of odonates, probably dating back to the Permian.

Download Full-text

Taxonomic utility of female copulation organs in Sericini chafers (Coleoptera, Scarabaeidae), with special reference to asymmetry

Contributions to Zoology ◽

10.1163/18759866-08402005 ◽

2015 ◽

Vol 84 (2) ◽

pp. 167-178 ◽

Cited By ~ 6

Author(s):

Alev Özgül-Siemund ◽

Dirk Ahrens

Keyword(s):

Sexual Selection ◽

Interspecific Variation ◽

Species Level ◽

The Other ◽

Female Genitalia ◽

Bursa Copulatrix ◽

Taxonomic Studies ◽

Strong Asymmetry ◽

Shape And Size ◽

Female Genital

Female genitalia are widely underrepresented in taxonomic studies. Here we investigate the morphological variation among female copulation organs for a group of scarab beetles (Sericini) with similar ecology, external morphology and copulation mechanics. We examined traits qualitatively and quantitatively based on 80 and 18 species (genus Pleophylla), respectively. Additionally we explored whether female genitalia are affected by asymmetry. The vast diversity of slerotised structures including their shapes illustrated the high taxonomic and phylogenetic utility of female genitalia in this group. The morphometric analysis of Pleophylla, confirmed that sclerotisations in the ductus bursae are very suitable for species-level taxonomic purposes. Stable interspecific variation is more hardly discernable in other parts such as the vaginal palps (shape and size) or the other membranous structures such as the shape of the bursa copulatrix. Asymmetric genitalia that arose multiple times independently among insects are found in most of the examined Sericini species. Asymmetries regarded either the bursa copulatrix, or both the bursa copulatrix and ductus bursae and comprised sclerotised and non-sclerotised structures being most common in modern Sericini. Here, highly asymmetric sclerotised structures are linked with strong asymmetry of the male copulation organs. Widespread asymmetry among megadiverse Sericini with a complex male-female genital asymmetry suggests that the shift to asymmetry is phylogenetically rather conserved. From the range of hypotheses, sexual selection seems to be the most reasonable to explain the evolution and stability of asymmetry in chafer genitalia.

Download Full-text

Baculum shape and paternity success in house mice: evidence for genital coevolution

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0150 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200150

Author(s):

Goncalo I. André ◽

Renée C. Firman ◽

Leigh W. Simmons

Keyword(s):

Sexual Selection ◽

Male Genitalia ◽

Female Genitalia ◽

Breeding Value ◽

House Mice ◽

Male Reproductive Success ◽

Relative Width ◽

Mus Musculus Domesticus ◽

Male And Female ◽

Paternity Success

Sexual selection is believed to be responsible for the rapid divergence of male genitalia, which is a widely observed phenomenon across different taxa. Among mammals, the stimulatory role of male genitalia and female ‘sensory perception’ has been suggested to explain these evolutionary patterns. Recent research on house mice has shown that baculum (penis bone) shape can respond to experimentally imposed sexual selection. Here, we explore the adaptive value of baculum shape by performing two experiments that examine the effects of male and female genitalia on male reproductive success. Thus, we selected house mice ( Mus musculus domesticus ) from families characterized by extremes in baculum shape (relative width) and examined paternity success in both non-competitive (monogamous) and competitive (polyandrous) contexts. Our analyses revealed that the relative baculum shape of competing males influenced competitive paternity success, but that this effect was dependent on the breeding value for baculum shape of the family from which females were derived. Our data provide novel insight into the potential mechanisms underlying the evolution of the house mouse baculum and lend support to the stimulatory hypothesis for the coevolution of male and female genitalia. This article is part of the theme issue ‘Fifty years of sperm competition’.

Download Full-text

Genital coupling, morphology and evolution of male holding structures in Cicadinae (Hemiptera: Cicadidae)

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz151 ◽

2019 ◽

Author(s):

Tatiana Petersen Ruschel ◽

Filipe Michels Bianchi ◽

Luiz Alexandre Campos

Keyword(s):

Sexual Selection ◽

Female Genitalia ◽

Male And Female ◽

Structural Interaction ◽

Functional Roles ◽

Evolutionary Studies ◽

Internal Genitalia ◽

Complex Features ◽

Stochastic Mapping ◽

Precopulatory Sexual Selection

Abstract Male and female genitalia include some of the most complex and morphologically diverse structures in Metazoa. Ornamentations in genitalia have been studied in several groups, and a variety of functional roles have been proposed. Although complex features of the genitalia have been observed in internal genitalia in cicadas, their functions have not yet been elucidated. These ornamentations, together with precopulatory sexual selection, make cicadas good models for evolutionary studies on genital coupling. We explore the structural interaction of male and female genitalia in Guyalna bonaerensis (Berg) (Cicadinae) and the morphology of male ornamentations in Cicadinae generally. We group these ornamentations into two traits according to their inferred function: anchoring or gripping. We analyse the theca and vesica of 24 species and perform ancestral trait reconstruction under maximum likelihood and stochastic mapping on a Bayesian tree. Ornamentations of the male vesica and the female seminal ampoule possibly ensure male attachment by working as an active lock to avoid the premature termination of intercourse. These ornamentations emerged independently in different lineages in Cicadinae, reinforcing the suggestion that they are important adaptations to achieve complete copulation. Our results foster questions for the field of sexual selection and associated mechanisms shaping the evolution of male and female genitalia.

Download Full-text