Oviposition strategies, host coercion and the stable exploitation of figs by wasps.
A classic example of a mutualism is the one between fig plants (Ficus) and their specialized and obligate pollinating wasps. The wasps deposit eggs in fig ovules, which the larvae then consume. Because the wasps derive their fitness only from consumed seeds, this mutualism can persist only if the wasps are prevented from laying eggs in all ovules. The search for mechanisms that can limit oviposition and stabilize the wasp-seed conflict has spanned more than three decades. We use a simple foraging model, parameterized with data from two Ficus species, to show how fig morphology reduces oviposition rates and helps to resolve the wasp-seed conflict. We also propose additional mechanisms, based on known aspects of fig biology, which can prevent even large numbers of wasps from ovipositing in all ovules. It has been suggested that in mutualistic symbioses, the partner that controls the physical resources, in this case Ficus, ultimately controls the rate at which hosts are converted to visitors, regardless of relative evolutionary rates. Our approach provides a mechanistic implementation of this idea, with potential applications to other mutualisms and to theories of virulence.
Centre for Ecology, Evolution and Conservation (CEEC) and the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK. douglas.yu@uea.ac.uk
Douglas W
DW
Yu
Jo
J
Ridley
Emmanuelle
E
Jousselin
Edward Allen
EA
Herre
Stephen G
SG
Compton
James M
JM
Cook
Jamie C
JC
Moore
George D
GD
Weiblen
D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology; D003163:Competitive Behavior / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D030681:Ficus / Q000033:anatomy & histology / Q000502:physiology*; D005638:Fruit; D008954:Models, Biological; D010058:Oviposition / Q000502:physiology*; D010802:Phylogeny; D011157:Population Dynamics; D013559:Symbiosis; D013997:Time Factors; D014863:Wasps / Q000502:physiology*