The effect of deceptive fruits on predispersal seed predation by birds in Pistacia lentiscus

Deceptive fruits (fruits containing empty seeds and seedless fruits) in the dioecious shrub Pistacia lentiscus L. (Anacardiaceae) remain attached to the plant throughout the dispersal season. This study addresses the hypothesis that deceptive fruits may contribute to parental fitness by reducing predispersal seed predation by granivorous birds because these fruits represent handling costs to predators and they prefer to forage selectively on shrubs with filled fruits. This study was run in two populations of P. lentiscus and finds that deceptive fruits reduce seed predation by granivorous birds but only in the population that presented higher P. lentiscus female density, and a higher variability in the percentage of deceptive fruits among P. lentiscus females. Under this scenario, the benefits of flying to another female might be higher than those of remaining in the same female searching filled seeds. By contrast, the costs of flying to other females, when they are scarce and have a similar percentage of deceptive fruits may be higher than the benefits.