title: Strategic sperm allocation under parasitic sex-ratio distortion.
abstract: Parasitic sex-ratio distorters are a major selective force in the evolution of host mating behaviour and mate choice. Here, we investigate sperm limitation in the amphipod Gammarus duebeni and the impact of the microsporidian sex-ratio distorter Nosema granulosis on sperm allocation strategies. We show that males become sperm limited after three consecutive matings and provide uninfected, high fecundity, females with more sperm than infected females. We show that sperm limitation leads to a decrease in female productivity. The outcome of sex-ratio distortion has been shown theoretically to be sensitive to the mating limits of males. Our results indicate that strategic sperm allocation under male rarity will have a greater impact on infected females and has the potential to regulate spread of parasitic feminisers in host populations.
authors.affiliation: School of Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Dunn
authors.forename: Tara
authors.initials: T
authors.lastname: Andrews
authors.forename: Hannah
authors.initials: H
authors.lastname: Ingrey
authors.forename: Joanna
authors.initials: J
authors.lastname: Riley
authors.forename: Nina
authors.initials: N
authors.lastname: Wedell
mesh_terms: D033304:Amphipoda / Q000382:microbiology*; D000818:Animals; D005260:Female; D007314:Insemination; D008297:Male; D016818:Nosema; D012744:Sex Ratio; D013076:Sperm Count; D013094:Spermatozoa / Q000166:cytology*