Bacterial Communities of Invasive Aphids Co-occurring on Novel Host Plants on Oahu

Abstract

Aphids have had invasive success in Hawaii that has been facilitated by rapid asexual reproduction. Another contributor to the invasive success of aphids in Hawaii involves the symbiotic interactions between aphids and their obligate and facultative endosymbionts, which are intracellular bacteria that dwell within hosts and constitute microbial communities. The obligate endosymbiont of aphids, Buchnera aphidicola, provides nutrients needed for the aphid’s survival and reproduction, while facultative endosymbionts may confer novel traits to the aphid. As both obligate and facultative endosymbionts affect aphid fitness, the composition and diversity of the aphid bacterial community may be important to the invasive success of aphids. An examination of the bacterial communities of two invasive aphid species across two novel host plants on the Island of Oahu was conducted to resolve the differences between aphid bacterial communities across aphid species, host plants, and sampling localities. The diversity within each aphid’s bacterial community did not significantly vary across aphid species, host plants, nor sampling locality. When assessing the diversity across the bacterial communities of multiple aphid individuals, bacterial communities differed significantly across aphid species as predicted since both obligate and facultative endosymbionts undergo vertical transmission from mother to clonal offspring. B. aphidicola was present in every sample, but the abundance of B. aphidicola did not vary across host plants. Additionally, facultative endosymbionts including Pseudomonas, Chryseobacterium, Wolbachia, Rickettsia, and Sphingomonas were discovered in some of the aphids sampled. Overall, this study concludes that aphid species is the most prominent factor that shapes the aphid bacterial community.