Hidden arsenal: Endosymbionts in arthropods, their role and possible implications for biological control success

Bacterial endosymbionts are common among arthropods including many important pest and beneficial insect species. These symbionts provide either an obligate function, performing essential reproductive or nutritive roles, or are facultative, influencing the ecology and evolution of their hosts in ways that are likely to impact biological control. This includes resistance against parasitoids and modification to parasitoid fecundity. Recent research has shown that endosymbionts are associated with exotic weevil pests found in New Zealand pasture, including the clover root weevil, Sitona obsoletus (=S. lepidus). The role of endosymbionts in insect biology and impacts on biological control is reviewed. For New Zealand plant protection scientists, endosymbiont research capability will provide important insights into interactions among insect pests, plant hosts and biological control agents, which may provide management opportunities for existing and future pest incursions in New Zealand.