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Insect herbivores can inflict substantial costs on plant reproductive success. Seed herbivory impacts directly by reducing the number of seeds and therefore the dispersal and reproductive potential of the plant. Fig trees, Ficus, provide keystone resources for tropical forests. The pollinating fig wasps develop inside figs, so consumption of unripe figs results in trees not only losing seeds but also their pollen dispersers. Selection to defend figs should therefore be strong. Seed herbivory is understudied in tropical forests and most data has been collected from fallen fruits. Here we use canopy sampling to identify fig-consuming larvae in central Panama and quantify both their consequences for the fig trees' reproductive success and the defensive value that ants provide against these larvae. Field surveys of 46 crops from nine fig species revealed that larvae could destroy up to 80% of figs on a tree. From seven Ficus species we barcoded (using COI) 51 individual fig consuming larvae (mainly Lepidoptera) that grouped into seven molecular operational taxonomic units. Lepidopteran larvae formed two feeding strategies, either stationary within a fig or tunneling between figs. Within the context of our study, stationary larvae were specialists whereas tunneling larvae were either specialists or generalists found on different Ficus species. Trees with ants had significantly fewer figs consumed by larvae (9% +/- 17% (mean +/- SD) for trees with azteca ants and 16% +/- 24% for trees with other ants) than did trees without ants (51% +/- 27%). Our results corroborate earlier findings that hosting ants can be an effective defensive mechanism for trees against seed herbivores or other antagonistic insects. Our study contributes to a wider body of research around the networks of insects associated with figs that highlights the importance of a multitrophic approach for understanding mutualism stability and persistence in the face of antagonism.

Insect seed predators are important agents of mortality for tropical trees, but little is known about the impact of these herbivores in rainforests. During 3 years at Khao Chong (KHC) in southern Thailand we reared 17,555 insects from 343.2 kg or 39,252 seeds/fruits representing 357 liana and tree species. A commented list of the 243 insect species identified is provided, with details about their host plants. We observed the following. (i) Approximately 43% of identified species can be considered pests. Most were seed eaters, particularly on dry fruits. (ii) Approximately 19% of parasitoid species (all Opiinae) for which we could determine whether their primary insect host was a pest or not (all Bactrocera spp. breeding in fruits) can be considered beneficials. (iii) The seeds/fruits of approximately 28% of the plant species in this forest were free of attack. Phyllanthaceae, Rubiaceae and Meliaceae were attacked relatively infrequently; in contrast, Annonaceae, Fabaceae, Sapindaceae and Myristicaceae were more heavily attacked. There was no apparent effect of plant phylogeny on rates of attack but heavily attacked tree species had larger basal area in the KHC plot than rarely attacked tree species. (iv) Insects reared from fleshy fruits were more likely to show relatively stable populations compared to insects reared from dry fruits, but this was not true of insects reared from dipterocarps, which appeared to have relatively stable populations throughout the study period. We tentatively conclude that insects feeding on seeds and fruits have little effect on observed levels of host abundance in this forest.

Mutualisms provide essential ecosystem functions such as pollination and contribute considerably to global biodiversity. However, they are also exploited by parasites that remove resources and thus impose costs on one or both of the mutualistic partners. The fig/pollinator interaction is a classic obligate mutualism; it is pantropical and involves >750 Ficus species and their host-specific pollinating wasps (family Agaonidae). Figs also host parasites of the mutualism that should consume pollinators or seeds, depending on their larval ecology. We collected data from a large crop of figs on Ficus glandifera var. brachysyce in a Sulawesi rainforest with an unusually high number of Eukoebelea sp. parasites. We found that these parasites have a significant negative correlation with fig seed production as well as with pollinator offspring production. Eukoebelea wasps form the basal genus in subfamily Sycophaginae (Chalcidoidea) and their larval biology is considered unknown. Our analysis suggests that they feed as flower gallers and impose direct costs on the fig tree, but a strategy including the consumption of pollinator larvae cannot be ruled out. We also present baseline data on the composition of the fig wasp community associated with F. glandifera var brachysyce and light trap catch data.

Mutualisms provide essential ecosystem functions such as pollination and contribute considerably to global biodiversity. However, they are also exploited by parasites that remove resources and thus impose costs on one or both of the mutualistic partners. The fig/pollinator interaction is a classic obligate mutualism; it is pantropical and involves >750 Ficus species and their host-specific pollinating wasps (family Agaonidae). Figs also host parasites of the mutualism that should consume pollinators or seeds, depending on their larval ecology. We collected data from a large crop of figs on Ficus glandifera var. brachysyce in a Sulawesi rainforest with an unusually high number of Eukoebelea sp. parasites. We found that these parasites have a significant negative correlation with fig seed production as well as with pollinator offspring production. Eukoebelea wasps form the basal genus in subfamily Sycophaginae (Chalcidoidea) and their larval biology is considered unknown. Our analysis suggests that they feed as flower gallers and impose direct costs on the fig tree, but a strategy including the consumption of pollinator larvae cannot be ruled out. We also present baseline data on the composition of the fig wasp community associated with F. glandifera var brachysyce and light trap catch data.