Clutch size: a major sex ratio determinant in fig pollinating wasps?
Under local mate competition, sex ratio theory predicts that increasing numbers of ovipositing females (foundresses) on a site should lead to higher proportions of males in their broods. Fig pollinators have confirmed this prediction. It is also predicted that with decreasing clutch size, solitary foundresses should produce increasing proportions of sons. We show this to be true. Further, when several females compete, brood size decreases. As a result, the proportion of males increases, and this could provide a mechanistic explanation of sex ratio response to numbers of colonizing females. Therefore, sex ratio data on fig wasps need to be reassessed to determine whether females 'count' other foundresses, as is generally accepted, or whether they simply 'count' the number of eggs that they lay.
Kjellberg
Finn
F
Centre d'Ecologie Fonctionnelle et Eevolutive, UMR 5175, Centre National de la Recherche Scientifique, 1919, Route de Mende, 34293 Montpellier, France. finn.kjellberg@cefe.cnrs.fr
Bronstein
Judith L
JL
van Ginkel
Glen
G
Greeff
Jaco M
JM
Moore
Jamie C
JC
Bossu-Dupriez
Nathalie
N
Chevolot
Malia e
Me
Michaloud
Georges
G
D000818:Animals; D005260:Female; D030681:Ficus / Q000469:parasitology*; D008297:Male; D010058:Oviposition; D012744:Sex Ratio; D014863:Wasps / Q000502:physiology*