Altruistic sperm donation in a sperm-dependent parthenogenetic hermaphrodite is stabilized by reciprocal sperm exchange
Nicolaas K. Michiels,Aline Kuhl +1 more
TLDR
This study investigates mating behaviour in a population of the sperm-dependent parthenogenetic, hermaphroditic flatworm Schmidtea polychroa and predicts that individuals should trade sperm and hence, only donate when receiving sperm from their partner, which contributes to the stability of apparently ‘altruistic’ sperm donation.Abstract:
Sperm-dependent parthenogenetic animals require sperm from an ‘altruistic’ mate in order to trigger embryogenesis, but without genetic contribution from the sperm donor. The stability of sperm donation is puzzling, particularly in populations that consist of sperm-dependent parthenogenetic hermaphrodites. Here, selection should favour total reduction of the male function, which would lead to population extinction. We investigated mating behaviour in a population of the sperm-dependent parthenogenetic, hermaphroditic flatworm Schmidtea polychroa. In this species, parthenogens possess a fully functional male reproductive system. We predicted that individuals should trade sperm and hence, only donate when receiving sperm from their partner. Results from 54 pairs indicate that conditional reciprocity is common, possibly even more so than in previously studied sexual conspecifics. In contrast to sexuals, however, parthenogens do not increase allocation to sperm with body size. Taken together, the data indicate that in order to receive sperm and ensure full maternal fertility, parthenogenetic S. polychroa must be able to produce and donate a minimum of self-sperm. As such, sperm trading contributes to the stability of apparently ‘altruistic’ sperm donation. This study is also the first convincing example of sperm trading in internally fertilizing hermaphrodites with a strong preference for the female role.read more
Citations
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Journal ArticleDOI
The Costs and Benefits of Occasional Sex: Theoretical Predictions and a Case Study
TL;DR: Despite costs associated with the production of less fertile tetraploids as sexual intermediates, the benefits of rare sex prevail in S. polychroa and may be sufficiently strong to prevent extinction of parthenogenetic populations.
Journal ArticleDOI
Occasional sex in an asexual polyploid hermaphrodite
TL;DR: It is concluded that genetic recombination does not necessarily require segregation and fusion within the same generation, as is the case in most sexual species.
Journal ArticleDOI
Do “sperm trading” simultaneous hermaphrodites always trade sperm?
Nils Anthes,Nico K. Michiels +1 more
TL;DR: Although trading of intromissions may be present, it is discussed why reciprocity in this species may also be a by-product of the mutual willingness of both partners to donate as well as receive sperm, and not an indicator of sperm trading.
Journal ArticleDOI
Paternal inheritance in parthenogenetic forms of the planarian Schmidtea polychroa.
TL;DR: Examination of sex-like processes in the planarian flatworm Schmidtea (Dugesia) polychroa detects two distinct processes: chromosome addition and chromosome displacement, which may explain the long-term persistence of the many purely parthenogenetic populations of S. polyChroa in northern Europe.
Journal ArticleDOI
Could sex be maintained through harmful males
TL;DR: It is suggested that males could differentially harm parthenogenetic females, for example, through harassment, toxic seminal fluids, or infanticide, while the adaptation behind the competitive advantage might differ from case to case.
References
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Book ChapterDOI
7 – Mating Conflicts and Sperm Competition in Simultaneous Hermaphrodites
TL;DR: Although constrained in their evolutionary response to sexual selection, it is clear that there is a scope for evolutionary arms races in hermaphrodites that may result in adaptations that are at least as diverse as those seen among gonochorists.
Journal ArticleDOI
Benefit to male sailfin mollies of mating with heterospecific females
TL;DR: It is shown that males gain a benefit by mating with female gynogens in an asexual-sexual complex of fish, and gynogenetic species might persist because selection favors males to be sexually parasitized.
Journal ArticleDOI
Evolutionary genetics and ecology of sperm-dependent parthenogenesis
TL;DR: The parasitic nature of sperm‐dependent parthenogenesis raises numerous ecological and evolutionary questions, and some genetic, ecological, and geographical consequences of sperm-dependentParthenogenesis in animals are considered.
Journal ArticleDOI
Incorporation of subgenomic amounts of DNA as compensation for mutational load in a gynogenetic fish
Manfred Schartl,Indrajit Nanda,Ingo Schlupp,Brigitta Wilde,Jörg T. Epplen,Michael Schmid,Jakob Parzefall +6 more
TL;DR: In the Amazon Molly fish Poecilia Formosa the authors have detected a process that appears to compensate for disadvantages of asexuality, namely incorporation of subgenomic amounts of DNA from a bisexual host species by microchromosomes.
Book ChapterDOI
8 – Sperm Competition in Molluscs
TL;DR: Different lines of evidence are presented which suggest that sperm competition might be important in the evolution of the reproductive behavior in some groups of molluscs and the adaptive significance of sperm polymorphism is still not known and needs to be assessed.