Bed bug preferences for host odor or aggregation odor are differentially modulated by physiological state in various odorscapes.

BACKGROUND: Bed bugs live in an ecologically and spatially restricted indoor habitat comprised of overlapping aggregation and host odors, and they traverse relatively short distances between blood-hosts and aggregation sites. Although many studies demonstrated aggregation or host odor preference respectively, the modulation of bed bug preferences between these divergent odors is poorly understood. Given the recurrent transitions of bed bugs between replete and hungry states, we evaluated the effects of six odorscapes containing aggregation and host skin odors on bed bug preferences. RESULTS: Hunger state modulated odor preference for aggregation and foraging in all tested odorscapes. Aggregation odor attracted both fed and unfed bed bugs. Host skin odor attracted unfed bed bugs but repelled recently fed bed bugs and the addition of carbon dioxide to host odor enhanced the behavioral responses. These findings suggest that orientation to aggregation sites in fed bed bugs is driven by two distinct odor-processing mechanisms for attractant and aversive odors. Unfed bed bugs discriminate between two attractive odors-aggregation and host odors-but host odor predominates over aggregation odor in driving their orientation behavior. CONCLUSION: Understanding the dynamic switching of odor preferences during the blood digestion cycle will guide the implementation of chemical lures in integrated pest management. Host odors alone and their co-emission with aggregation pheromone repelled fed bed bugs from traps. Conversely, unfed bed bugs had a strong preference for host odor emitted either alone or with aggregation odor. Therefore, the independent use of either host or aggregation odor lures and their co-emission from the same trap should be carefully considered. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.