{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T08:47:24Z","timestamp":1772268444242,"version":"3.50.1"},"reference-count":43,"publisher":"PeerJ","license":[{"start":{"date-parts":[[2022,11,24]],"date-time":"2022-11-24T00:00:00Z","timestamp":1669248000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100013345","name":"Naturalis Biodiversity Center","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100013345","id-type":"DOI","asserted-by":"crossref"}]},{"name":"CNRS"},{"name":"Agence Nationale de la recherche","award":["ANR-20-CE13-0006"],"award-info":[{"award-number":["ANR-20-CE13-0006"]}]},{"DOI":"10.13039\/501100004219","name":"Paul Scherrer Institute","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100004219","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Asymmetric genitalia have repeatedly evolved in animals, yet the underlying causes for their evolution are mostly unknown. The fruit fly\n                      <jats:italic>Drosophila pachea<\/jats:italic>\n                      has asymmetric external genitalia and an asymmetric phallus with a right-sided phallotrema (opening for sperm release). The complex of female and male genitalia is asymmetrically twisted during copulation and males adopt a right-sided copulation posture on top of the female. We wished to investigate if asymmetric male genital morphology and a twisted gentitalia complex may be associated with differential allocation of sperm into female sperm storage organs.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We examined the internal complex of female and male reproductive organs by micro-computed tomography and synchrotron X-ray tomography before, during and after copulation. In addition, we monitored sperm aggregation states and timing of sperm transfer during copulation by premature interruption of copulation at different time-points.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The asymmetric phallus is located at the most caudal end of the female abdomen during copulation. The female reproductive tract, in particular the oviduct, re-arranges during copulation. It is narrow in virgin females and forms a broad vesicle at 20 min after the start of copulation. Sperm transfer into female sperm storage organs (spermathecae) was only in a minority of examined copulation trials (13\/64). Also, we found that sperm was mainly transferred early, at 2\u20134 min after the start of copulation. We did not detect a particular pattern of sperm allocation in the left or right spermathecae. Sperm adopted a granular or filamentous aggregation state in the female uterus and spermathecae, respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>No evidence for asymmetric sperm deposition was identified that could be associated with asymmetric genital morphology or twisted complexing of genitalia. Male genital asymmetry may potentially have evolved as a consequence of a complex internal alignment of reproductive organs during copulation in order to optimize low sperm transfer rates.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.7717\/peerj.14225","type":"journal-article","created":{"date-parts":[[2022,11,24]],"date-time":"2022-11-24T03:37:56Z","timestamp":1669261076000},"page":"e14225","source":"Crossref","is-referenced-by-count":2,"title":["No evidence for asymmetric sperm deposition in a species with asymmetric male genitalia"],"prefix":"10.7717","volume":"10","author":[{"given":"Sanne","family":"van Gammeren","sequence":"first","affiliation":[{"name":"Naturalis Biodiversity Center, Leiden, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Lang","sequence":"additional","affiliation":[{"name":"Universit\u00e9 Paris Cit\u00e9, CNRS - Institut Jacques Monod, Paris, France"},{"name":"Institut Diversit\u00e9, Ecologie et 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