Previous studies have not made it clear whether parasitoid specialisation on Ficus is characterised by host switching i.e. different populations reproducing separately on different Ficus species (divergent selection), or, whether a population uses multiple host species.

Dr. Michael J. McLeish of Xishuangbanna Tropical Botanical Garden (XTBG) and his international colleagues conducted a study to test the hypothesis that a parasitoid population is able to reproduce in syconia of more than one Ficus species. They discussed the interactions between parasitoids and the Ficus species present in a forest patch of Uganda in context with populations in Southern Africa.

The researchers used parsimony-based and probabilistic methods to discriminate between within-species and between-species haplotype divergence and infer a phylogeny including a nuclear marker to validate species relationships. They assessed the morphological variation among putative species lineages to compare with genetic delimitation approaches.

They tested: i) whether single or multiple populations/species of Arachonia were present in Kibale Forest; ii) their relationship with specimens collected widely over Eastern and Southern Africa; and iii) haplotype structuring according to the Ficus species they were reared from.

The study demonstrated that Arachonia species in Africa have conservative host plant associations among Ficus subsections Sycomorus (section Sycomorus) and Caulocarpe (section Galoglychia).Their findings indicated that a parasitoid population of Arachonia was able to reproduce in multiple Ficus species in the same forest patch in the period concomitant with the developmental time of a single generation.

The study entitled “Host-Plant Species Conservatism and Ecology of a Parasitoid Fig Wasp Genus (Chalcidoidea; Sycoryctinae; Arachonia)” has been published in PLoS ONE 7(9): e44804. doi:10.1371/journal.pone.0044804