Cost limitation through constrained oviposition site in a plant-pollinator/seed predator mutualism

Détails

ID Serval
serval:BIB_AA043E45E2F7
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Cost limitation through constrained oviposition site in a plant-pollinator/seed predator mutualism
Périodique
Functional Ecology
Auteur(s)
Labouche A.M., Bernasconi G.
ISSN
0269-8463
Statut éditorial
Publié
Date de publication
2013
Volume
27
Numéro
2
Pages
509-521
Langue
anglais
Résumé
Mutualism often involves reciprocal exploitation due to individual selection for increased benefits even at the expense of the partner. Therefore, stability and outcomes of such interactions crucially depend on cost limitation mechanisms. In the plant, pollinator /seed predator interaction between Silene latifolia (Caryophyllaceae) and Hadena bicruris (Lepidoptera: Noctuidae), moths generate pollination benefits as adults but impose seed predation costs as larvae. We examined whether floral morphology limits over-exploitation by constraining oviposition site. Oviposition site varies naturally inside vs. outside the corolla tube, but neither its determinants nor its effect on the interaction have been investigated. In a common garden with plants originating from eight populations, corolla tube length predicted oviposition site, but not egg presence or pollination efficiency, suggesting that long corolla tubes constrain the moth to lay eggs on petals. Egg position was also predicted by the combined effect of corolla tube and moth ovipositor lengths, with shorter ovipositor than corolla tube resulting in higher probability for eggs outside. Egg position on a given plant was repeatable over different exposure nights. When egg position was experimentally manipulated, eggs placed on the petal resulted in significantly fewer successful fruit attacks compared with eggs placed inside the corolla tube, suggesting differences in egg/larval mortality. Egg position also differently affected larval mass, fruit mass and fruit development. Our results indicate that constraining oviposition site through a long corolla tube reduces seed predation costs suffered by the plant without negatively affecting pollination efficiency and, hence may act to limit over-exploitation. However, the net effects of corolla tube depth variation on this interaction may fluctuate with extrinsic factors affecting egg mortality, and with patterns of gene flow affecting trait matching between the interacting species. The intermediate fitness costs incurred by both plant and insect associated with the different egg positions may reduce selective pressures for this interaction to evolve towards antagonism, favouring instead a mutualistic outcome. While a role for oviposition site variation in cost limitation is a novel finding in this system, it may apply more generally also to other mutualisms involving pollinating seed predators.
Mots-clé
egg laying, floral morphology, floral traits, fruit abortion, Hadena bicruris, parasitism, pollination, seed predation, Silene alba, Silene latifolia
Web of science
Création de la notice
10/05/2013 11:17
Dernière modification de la notice
20/08/2019 16:14
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