Population Genomics Approaches Identify a Cryptic, Emerging Generalist Pest Complex

Information about biological traits essential for pest management, such as species identity, diet and movement often require laborious and time-intensive studies on pest natural history, in both laboratory and field settings. However, new agricultural pest threats are continually emerging, often requiring prompt responses with limited information. Using a combination of molecular gut content analysis and RAD-seq, we examined the species identities, plant diet composition, and population genetic structure of an emerging and important agricultural pest in the US, the peanut burrower bug, Pangaeus bilineatus Say (Hemiptera, Cydnidae). We found that two, morphologically similar, burrowing bug species (including P. bilineatus) were commonly caught in light traps near peanut fields, one of which (Dallasiellus lugubris) was not previously considered a pest of peanut. Molecular gut content analysis revealed a wide, but somewhat distinct, variety of plants among the diets of both bug species. Surprisingly, peanut was a rare part of the diet of either species. RAD-seq analysis revealed evidence consistent with weak isolation-by-distance and modest spatial genetic differentiation for both species. Together, these results suggest a potential pest complex where previously only one species was in focus. Moreover, their broad diets and spatially restricted population dispersal patterns may also explain the sporadic nature of damage that has been recorded for this potential pest complex. Responses to emerging pest challenges can benefit from insights generated by population genomics techniques, opening up new avenues for research and supporting efforts to quickly tailor management strategies for novel pests.