Molecular analysis of microbial populations associated with two tropical stinkbug species (Pentatomidae)
Mentor:Shana Goffredi, Assistant Professor of Biology, Occidental College
Symbiotic relationships between bacteria and insects are known to provide essential nutrients and confer detoxification abilities. Two tropical stinkbugs, Sibaria englemani and Edessa sp. were investigated to determine microbial diversity and the possibility of a symbiotic association with bacteria. Using 16S rRNA PCR amplification and sequencing, it was determined that the microbial community of S. englemani and Edessa was dominated by a single bacterial type at all stages of life (nymph to adult). Sibaria’s dominant bacteria was found to range from 77-100% of the total microbial community, while Edessa’s dominant bacteria composed 100% of the microbial community in all individuals. Phylogenetic placement of the dominant microbes showed a close relationship to other insect-associated bacteria within the gammaproteobacteria. With access to eggs and newly hatched nymphs, possible modes of transmission of bacteria were also investigated. Bacterial presence in the eggs, different nymph stages and adults of Edessa suggest vertical transmission, however DNA optimization of Sibaria eggs must be performed before we can speculate on the transmission in this species. These results indicate the likely presence of a true symbiosis between these two stinkbugs and bacteria, but also provided possibilities for further research in determining the mode of transmission for Sibaria.