Evolution of sperm morphology in a crustacean genus with fertilization inside an open brood pouch

Duneau, David and Möst, Markus and Ebert, Dieter. (2022) Evolution of sperm morphology in a crustacean genus with fertilization inside an open brood pouch. Peer Community Journal, 2. e63.

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Official URL: https://edoc.unibas.ch/93124/

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Sperm is the most fundamental male reproductive feature. It serves the fertilization of eggs and evolves under sexual selection. Two components of sperm are of particular interest, their number and their morphology. Mode of fertilization is believed to be a key determinant of sperm length across the animal kingdom. External fertilization, unlike internal, favors small and numerous sperm, since sperm density is thinned out in the environment. Here, we study the evolution of sperm morphology in the genus Daphnia, where fertilization occurs in a receptacle, the brood pouch, where sperm can constantly be flushed out by a water current. Based on microscopic observations of sperm morphologies mapped on a phylogeny with 15 Daphnia and 2 outgroup species, we found that despite the internal fertilization mode, Daphnia have among the smallest sperm recorded, as would be expected with external fertilization. Despite being all relatively small compared to other arthropods, sperm length diverged at least twice, once within each of the Daphnia subgenera Ctenodaphnia and Daphnia. Furthermore, species in the latter subgenus also lost the ability of cell compaction by extracellular encapsulation and have very polymorphic sperm with long, and often numerous, filopodia. We discuss the different strategies that Daphnia evolved to achieve fertilization success in the females’ brood pouch.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Integrative Biologie > Evolutionary Biology (Ebert)
UniBasel Contributors:Ebert, Dieter and Duneau, David
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Peer Community In
Note:Publication type according to Uni Basel Research Database: Journal article
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edoc DOI:
Last Modified:13 Feb 2023 09:58
Deposited On:31 Jan 2023 14:22

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