Microbes come along for the ride: Cryptic players in insect invasion and biological control

Identification of the species and geographic origin of invasive species has long been understood to improve the odds of finding and successfully matching biological control agents for successful pest management. Less often addressed is the possibility that microbial symbionts of either invader or biological control agent may be involved in the success or failure of reproduction and spread of their host in the area of origin. Yet bacterial and fungal symbionts are now recognized to be near ubiquitous players in the reproduction and ecology of terrestrial arthropods. They may be beneficial and contribute to nutrition or defense, or may selfishly manipulate host reproduction in ways that boosts their own transmission to the next host generation at the expense of their host.

I will argue that knowing the symbionts of both invader and biological control agent will give us the most power to bring about the outcome we want. All members of the microbiome are unlikely to be beneficial, and we may want to manipulate the symbiont complement before introduction. Symbiont community members may also give us more precise information about the geographic origins of introduced arthropods, or give us targets for manipulation or control. Examples from our work include a reconstruction of key elements of the biological control program for of ash whitefly, and an exploration of the biology of a leaf-footed bug that acquires its symbiont from the environment and has an expanding geographic range.