Ecology of parasite Sycophilomorpha sp. on Ficus altissima and its effect on the fig-fig wasp mutualism.

Figs and their pollinating wasps are a classic example of an obligate mutualism. In addition, figs are parasitized by a suite of non-mutualistic wasps whose basic ecology is largely undescribed. Sycophilomorpha (subfamily Epichrysomallinae) fig wasps are ovule gallers and the genus contains only 1 described species. An undescribed Sycophilomorpha species parasitized Ficus altissima at Xishuangbana, Southwestern China. The wasp was observed ovipositing on the tiny immature figs that were still concealed beneath the involucral bracts. A Sycophilomorpha wasp oviposited on more than 1 fig and spent long time-periods to lay large clutches on a single fig. The wasps naturally occurred on all 7 sampled trees, but the occurrence of wasps was significantly different among trees, crops and months. These wasps were able to prevent unpollinated figs from being aborted, and their offspring were able to develop in the figs that otherwise had no pollinator wasps or seeds. The Sycophilomorpha wasp had a detrimental effect on the fig-fig wasp mutualism. Figs in which Sycophilomorpha wasps were present, produced significantly fewer seeds, pollinators and cheaters. However, the abundance of Sycophilomorpha in a fig was only significantly negatively correlated with pollinator production and not seed or cheater production. Our study illustrates a previously unknown fig wasp niche and expands our understanding of factors that can affect the fig-fig wasp interaction.