Parasitism of a pollinator fig wasp: mortalities are higher in figs with more pollinators, but are not related to local densities of figs

Abstract

Fig trees (Ficus) and their species‐specific pollinators (Agaonidae) represent a remarkable example of a coevolved mutualism. A number of non‐pollinating fig wasps (gallers and parasitoids,NPFW) are also an integral part of the mutualism, but have a negative impact on the reproductive success of the mutualists. MostNPFWbelong to subfamilies only associated with figs and clearly have a long association with the plants and their pollinators.In the present study, the costs imposed by an undescribed parasitoidSycoscaptersp. on its host pollinatorKradibia (=Liporrhopalum) tentacularisof a dioecious fig treeFicus montanamaintained under glasshouse conditions are described.It was asked whether pollinator numbers and sex ratios are changed by the presence or absence of parasitoids within individual figs. The effect of fig densities on parasitism rates at two spatial scales and within the general glasshouse population was also recorded. Parasitoid aggregation in relation to pollinator densities inside figs was also examined.Sycoscaptersp. significantly reduced the numbers of pollinators emerging from the figs, but host sex ratios were not distorted. The parasitoid showed host density independence at both spatial scales of fig densities, but targeted individual figs that contained higher initial densities of pollinators.