On the relative effect of spawning asynchrony, sperm quantity, and sperm quality on paternity under sperm competition in an external fertilizer
How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these situations? The Arctic charr (Salvelinus alpinus) is an external fertilizer experiencing intense male-male competition over reproductive opportunities including sperm competition. To compensate for their disadvantage the sneaker males, which often spawn out of synchrony with the female, produce more and faster sperm than the guarding males. We used controlled in vitro fertilization trials with experimentally produced dominant and subordinate, sneaker males to test what effect relative synchrony in gamete release, sperm quality (i.e., motility and velocity) and sperm quantity have on a male’s fertilization success in pair-wise sperm competitions. When the sneaker males released ejaculates after the guarding male there was no overall difference in fertilization success. The quality (i.e., motility and velocity) of a male’s sperm relative to that of the competing male was the best predictor of male fertilization success regardless of their mating tactic and spawning synchrony. The relative number of sperm cells also had an effect on fertilization success, but mainly when the dominant and sneaker male ejaculated synchronously. Our close imitation of natural sperm competition in charr shows that the sneaker males of external fertilizing species may fully compensate for their disadvantaged mating role by producing ejaculates of higher quality—an adjustment strangely not met by dominants.
CitationFrontiers in Ecology and Evolution 3(2015) s. 1-
MetadataShow full item record
The following license file are associated with this item:
Showing items related by title, author, creator and subject.
The relative effect of parasites and social status on sperm traits in Arctic charr Figenschou, Lars; Folstad, Ivar; Rudolfsen, Geir; Hanssen, Sveinn Are; Kortet, Raine; Skau, Philip; Killie, Jan Eirik; Oskam, Irma Caroline; Strand, Harald (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)Sperm production and sperm swimming speed, which most likely affect fertilization under sperm competition, are modified by proximate mechanisms. In a comprehensive observational study of free-living and reproductively active Arctic charr (Salvelinus alpinus), we examined the possible modulating effects of male social status (including ornamental development), parasite intensities, and immunity ...
Status specific tailoring of sperm behavior in an external fertilizer Egeland, Torvald Blikra; Rudolfsen, Geir; Nordeide, Jarle Tryti; Folstad, Ivar (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-24)Why dominant males experiencing intense sperm competition sometimes show low investments in sperm production is not always obvious. One well-documented example is that of the external fertilizing teleost, the Arctic charr (Salvelinus alpinus), where individuals becoming dominant reduce sperm production and sperm swimming speed in water compared to subordinates. Here, we report how ovarian ...
Do the fastest sperm within an ejaculate swim faster in subordinate than in dominant males of Arctic char? Vaz Serrano, Jonathan; Folstad, Ivar; Rudolfsen, Geir; Figenschou, Lars (Journal article; Tidsskriftartikkel; Peer reviewed, 2006)Theoretical models predict that subordinate males should have higher sperm velocity to compensate for their disadvantaged mating role and because they experience sperm competition more frequently than dominant males. Differences in mean velocity between sperm of dominants and subordinates in the predicted direction are also documented for a few species, including the Arctic char, Salvelinus alpinus ...