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Sperm competition and offspring viability at hybridization in Australian tree frogs, Litoria peronii and L. tyleri

journal contribution
posted on 2023-05-17, 00:59 authored by Sherman, CDH, Erik WapstraErik Wapstra, Olsson, M
Hybridization between closely related species often leads to reduced viability or fertility of offspring. Complete failure of hybrid offspring (post-zygotic hybrid incompatibilities) may have an important role in maintaining the integrity of repro- ductive barriers between closely related species. We show elsewhere that in Peron�s tree frog, Litoria peronii, males more closely related to a female sire more offspring in sperm competition with a less related rival male. Observations of rare �phenotypic intermediate� males between L. peronii and the closely related L. tyleri made us suggest that these related- ness effects on siring success may be because of selection arising from risks of costly hybridization between the two species. Here, we test this hypothesis in an extensive sperm competition experiment, which shows that there is no effect of species identity on probability of fertilization in sperm competition trials controlling for sperm concentration and sperm viability. Instead, there was a close agreement between a male�s siring success in isolation with a female and his siring success with the same female in competition with a rival male regardless of species identity. Offspring viability and survival, however, were strongly influenced by species identity. Over a 14-day period, hybrid offspring suffered increasing mortality and developed more malformations and an obvious inability to swim and right themselves, leading to compromised probability of survival. Thus, hybridization in these sympatric tree frogs does not compromise fertilization but has a strong impact on offspring viability and opportunity for reinforcement selection on mate choice for conspecific partners.

History

Publication title

Heredity

Volume

104

Pagination

141-147

ISSN

0018-067X

Department/School

School of Natural Sciences

Publisher

Nature Publishing Group

Place of publication

Macmillan Building, 4 Crinan St, London, England,

Rights statement

Copyright © 2009 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.

Repository Status

  • Restricted

Socio-economic Objectives

Fresh, ground and surface water biodiversity

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