The sagebrush-steppe is an important ecosystem in the northwestern United States. Sagebrush plays an essential role in the hydrologic cycle, sustains grazing for wildlife, and provides a crucial nesting habitat for numerous small animals including the endangered sage grouse. A single sagebrush is host to a community of insects including aphids, ants, and ladybird beetles. These insects are often infected with one or more facultative (or secondary) symbiotic bacteria, notably Wolbachia, Rickettsia, and Hamiltonella. These endosymbionts have a variety of effects on their hosts, including reproductive manipulation, pesticide resistance, heat tolerance, and protection from parasites. Recent studies have also found that insect endosymbionts can affect insect-plant interactions through expanding host plant range and use, as well as affecting plant physiology to benefit the insects. As they cause such a variety of effects, the composition of endosymbionts within insect communities may be an important factor in ecosystem interactions. The aim of our study is to conduct molecular genetic surveys of the endosymbionts within insect populations collected from Artemisia tridentata (big sagebrush) in southwestern Idaho. We will then experimentally determine how the endosymbiont composition may be manipulating the insect-sagebrush interactions, thus impacting the diverse sagebrush ecosystem overall.

Microscopic manipulators: how bacterial symbionts of insects affect the sagebrush ecosystem.