Ecology of parasiteSycophilomorphasp. onFicus altissimaand its effect on the fig-fig wasp mutualism

Abstract

S U M M A R YFigs 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.

The dominant exploiters of the fig/pollinator mutualism vary across continents, but their costs fall consistently on the male reproductive function of figs

“…However, we also found wasps from several other taxa (Table 2). Large wasps like these seem to occur as rare members of most fig wasp communities and can sometimes prevent abortion of unpollinated syconia or decrease seed or pollinator production by draining resources (Compton, 1993;West & Herre, 1994;Peng et al, 2010). They develop in large galls emanating from syconium wall tissue and are all relatively rare (Table 3).…”

Non‐pollinating Fig Wasps Decrease Pollinator and Seed Production in Ficus andicola (Moraceae)

“…Kerdelhué et al (2000) found a negative effect on F. ovata and F. vallis-choudae caused by Phylosycus monstruosus and Apocryptophagus sp., respectively. In China, Peng et al (2010) reported that syconia of Ficus altisima parasitized by Sycophilomorpha spp. fed on the seeds of Ficus citrifolia.…”

“…fed on the seeds of Ficus citrifolia. In China, Peng et al (2010) reported that syconia of Ficus altisima parasitized by Sycophilomorpha spp. produced fewer seeds.…”

“…This non-pollinating wasp fauna includes galling species, whose larvae develop in flower ovaries or in the syconium tissue, non-galling species that feed on the galls induced by pollinators (kleptoparasites), and parasitoids of the galling wasps. The occurrence and effects on seed production of nonpollinating wasps that use the external flowers have not, however, been clearly documented (though see Kerdelhué & Rasplus 1996, West et al 1996, Kerdelhué et al 2000, Elias et al 2007, Peng et al 2010. Although external flowers would be easier to reach, the majority of non-pollinating galling wasps tend to use internal flowers.…”

“…By laying in the same flowers, non-pollinating galling wasps compete with pollinators, decreasing the numbers that emerge from syconia (West & Herre 1994, Kerdelhué & Rasplus 1996, West et al 1996. The occurrence and effects on seed production of nonpollinating wasps that use the external flowers have not, however, been clearly documented (though see Kerdelhué & Rasplus 1996, West et al 1996, Kerdelhué et al 2000, Elias et al 2007, Peng et al 2010.…”