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Abstract

Sexual selection theory predicts a positive correlation between relative parental investment
and mate choice. In syngnathid fishes (seahorses and pipefish), males brood offspring in
specialized brooding structures. While female-female mating competition has been demonstrated
in some pipefishes, all seahorses (genus
Hippocampus
) studied to date have been
found to have conventional sex roles with greater male–male competition for access to
mates despite possessing the most complex brood structures in the family. Although
multiple mating is common in pipefish, seahorses are again exceptional, exhibiting strict
genetic monogamy. Both demographic and behavioural explanations have been offered to
explain the lack of multiple mating in seahorse species, but these hypotheses have not yet
been explicitly addressed. We investigated mating systems and brood parentage of the
pot-bellied seahorse,
Hippocampus abdominalis
, a temperate-water species that is socially
promiscuous with conventional sex roles in laboratory populations. We observed promiscuous
courtship behaviour and sex-role reversal in high density, female-biased field populations
of
H. abdominalis
. We hypothesize that sex roles are plastic in
H. abdominalis
, depending
on local population density and sex ratio. Despite promiscuous courtship behaviour, all
assayed male seahorses were genetically monogamous in both laboratory and wild
populations. Physiological limitations associated with embryo incubation may explain
the absence of multiple mating in seahorses and may have played an important role in the
development of the unique reproductive behaviour typical in these species.

Item Type:	Article
Authors/Creators:	Wilson, AB and Martin-Smith, KM
Keywords:	mating system, microsatellite genotyping, sex-role reversal, Syngnathidae, traditional sex roles
Journal or Publication Title:	Molecular Ecology
Publisher:	Blackwell Publishing
ISSN:	0962-1083
DOI / ID Number:	https://doi.org/10.1111/j.1365-294X.2007.03243.x
Additional Information:	The definitive version is available at www.blackwell-synergy.com
Item Statistics:	View statistics for this item

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