Transcriptome analysis of the male polymorphisms of fig wasp species Philotrypesis tridentata.

Intraspecific male polymorphism exhibiting extreme differences in morphology, behavior and life history presents good opportunities to explore adaptation mechanisms to different environments. In this study, we examined the transcriptomic differences between wingless and winged morphs of a fig wasp species Philotrypesis tridentata to investigate molecular basis to maintain polymorphisms. The winged male adults fly outside fig syconia to mate, while the wingless only stay and mate inside fig syconia where they have developed. We identified 2,391 differentially expressed genes (DEGs) with 1,396 highly expressed in winged morphs and 995 in wingless morphs. We performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses on the DEGs and differential alternative splicing genes and analyzed the top ten DEGs with the highest differential expression in each morph. The results showed that genes related to biosynthesis processes, lipid metabolism, energy production, flight and defense of the complex environments outside fig syconia were up-regulated in winged morphs. Genes involved in substance and energy metabolism and chemical reception were up-regulated in wingless morphs which might relate to their living inside fig syconia. The differences in highly expressed genes between two morphs prove adaptation of P. tridentata male polymorphism to different living environments.