1st Place: D3059: Foraging preference of cigarette beetle and rice weevil when dispersing to novel food patches with and without microbes

Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Lasioderma serricorne (F.) (Coleoptera: Ptinidae) cause extensive damage after harvest. Stored product arthropods are attracted to, repelled, or unaffected by microbial cues in a recent meta-analysis. While prior research has identified possible associated symbioses between stored product insects and microbes, little is known about what modulates stored product insects’ preference for a particular host habitat or whether microbes play a role in mediating these interactions. Thus, the aim of the current study was to evaluate whether the preference of S. oryzae and L. serricorne host habitats is modulated by microbial infestation. We used a linear dispersal apparatus that contained two foraging patches separated by a PVC pipe to allow insects to move throughout and placed autoclaved grain (sanitized), grain inoculated with Aspergillus-flavus, and/or grain from storage in the two habitat patches. We introduced a total of 30 insects into the release patch in the center of the apparatus, gave them 72 hr to disperse and choose one of the two foraging patches on either side while varying treatments so all pairwise treatment combinations were tested. We recorded insects dispersing to each patch and the progeny produced in each patch after 6 weeks. Our study found that microbes modulated the preference and establishment of both species. We discuss the results in light of each species’ life history traits. Our data suggests that microbial contamination modulates habitat preference and also impacts reproductive fitness for both species, which has repercussions for food safety and pest management.