Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm competition

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Etat: Public
Version: Final published version
ID Serval
serval:BIB_2B2DEEBC5CFC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm competition
Périodique
Ecology and Evolution
Auteur(s)
Ala-Honkola O., Ritchie M.G., Veltsos P.
ISSN
2045-7758
Statut éditorial
Publié
Date de publication
2016
Volume
6
Numéro
6
Pages
1679-1691
Langue
anglais
Résumé
Postmating but prezygotic (PMPZ) interactions are increasingly recognized as a potentially important early-stage barrier in the evolution of reproductive isolation. A recent study described a potential example between populations of the same species: single matings between Drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (Vancouver) to penetrate the eggs of the other population (Colorado). As the natural mating system of D. montana is polyandrous (females remate rapidly), we set up double matings of all possible crosses between the same populations to test whether competitive effects between ejaculates influence this PMPZ isolation. We measured premating isolation in no-choice tests, female fecundity, fertility and egg-to-adult viability after single and double matings as well as second-male paternity success (P-2). Surprisingly, we found no PMPZ reproductive isolation between the two populations under a competitive setting, indicating no difficulty of sperm from Vancouver males to fertilize Colorado eggs after double matings. While there were subtle differences in how P-2 changed over time, suggesting that Vancouver males' sperm are somewhat less competitive in a first-male role within Colorado females, these effects did not translate into differences in overall P-2. Fertilisation success can thus differ dramatically between competitive and noncompetitive conditions, perhaps because the males that mate second produce higher quality ejaculates in response to sperm competition. We suggest that unlike in more divergent species comparisons, where sperm competition typically increases reproductive isolation, ejaculate tailoring can reduce the potential for PMPZ isolation when recently diverged populations interbreed.
Mots-clé
Ejaculate tailoring, ejaculate-ejaculate interaction, postcopulatory sexual selection, reproductive isolation, speciation
Web of science
Open Access
Oui
Création de la notice
18/04/2016 12:46
Dernière modification de la notice
20/08/2019 14:10
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