Posted by Anna Nordén
Next week I suggest we discuss a paper about size-assortative mating induced by mate choice in simultaneous hermaphrodites. I find the meta-analysis when they compare hermaphrodites mating unilaterally or reciprocally most interesting.
Looking forward to hear what you think. See you next Tuesday (Sep 22nd), at 10 in Argumentet. Fika will be provided as usual.
Title: Size-assortative mating in simultaneous hermaphrodites: an experimental test and a meta-analysis
Abstract: Assortative mating by size has been argued to be widespread in the
animal kingdom. However, the strength of size-assortative mating is
known to vary considerably between species and the underlying mechanisms
promoting this inter-specific variation remain largely unexplored.
Size-assortative mating has been proposed to be particularly strong in
simultaneous hermaphrodites, i.e. organisms that produce male and female
gametes at the same time. Here, we build on this hypothesis by arguing
that size-assortative mating mediated by sexual selection is generally
stronger in reciprocally mating hermaphrodites compared with
unilaterally mating species and separate-sexed organisms. We report a
series of empirical tests suggesting that size-assortative mating in the
unilaterally copulating freshwater snail Physa acuta
is caused by spatial clustering of similar-sized individuals and not by
mate choice. In addition, we present a meta-analysis testing, for the
first time, the hypothesis that sexual selection-mediated
size-assortative mating is stronger in reciprocally copulating
simultaneous hermaphrodites. Overall, we found significant
size-assortative mating across 18 tested species and substantial
inter-specific variation. Importantly, part of this variation can be
explained by mating type, providing support for the hypothesis that
size-assortative mating is stronger in reciprocally mating
hermaphrodites compared with unilaterally mating species. We highlight
potential pitfalls when testing for sexual selection-mediated
size-assortative mating and discuss the need for more experimental and
comparative approaches in order to resolve the observed variation in the
strength of size-assortative mating among species.