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Sperm ageing after ejaculation can generate paternal environmental effects
that impact offspring fitness. In many species, female reproductive fluids
(FRFs), i.e. ancillary fluids released by eggs or within the female
reproductive tract, may protect sperm from ageing and can additionally
interact with sperm to influence offspring viability. This raises the
intriguing prospect that FRFs may alleviate paternal effects associated
with sperm ageing. Here, we test this novel hypothesis using the broadcast
spawning mussel, Mytilus galloprovincialis. We show that incubating sperm
in FRF prior to fertilisation increases offspring viability and that these
effects occur independently of sperm age. Our results provide novel
evidence that FRFs allow females to selectively bias fertilisation toward
higher quality sperm within an ejaculate, which in turn yields more viable
offspring. We consider this FRF-mediated paternal effect in the context of
female physiological control over fertilisation and the transgenerational
effects of female-regulated haploid selection.
39 views reported since publication in 2023.