| Urban and structural pests cause considerable harm and damage to humans and human structures. Therefore, it is critical that we understand their biology, behavior, health risks, and management. In the following studies, I investigated bed bug (Cimex lectularius) evolution, the behavioral responses of bed bugs to heat, and environmental risks associated with bed bugs and cockroaches.;Cimex lectularius was recently found to have two genetically and morphologically distinct host-associated lineages: one associated with humans (HA) and one associated with bats (BA). However, the mechanisms responsible for maintaining genetic separation between lineages remain unclear. In the first study, aggregation behavior was evaluated among host associated lineages of bed bugs (HA, BA) and bat bugs (Cimex pipistrelli). Using shelter-choice assays, we found no evidence for aggregation fidelity, with lineages and species aggregating indiscriminately. Thus, we conclude that aggregation fidelity is not a viable mechanism for maintaining genetic differentiation among host-associated populations.;In the second study, reproductive compatibility was evaluated with mating crosses among 6 populations of bed bugs representing different host-associations (HA, BA) and geographic locations (U.S.A., Europe). Results indicated that HA bed bugs had higher fecundity that BA bed bugs, but all inter-lineage crosses produced viable offspring, even between HA and BA bed bugs. We conclude that reproductive barriers are unlikely to prevent gene flow, and thus other mechanisms (behavior, physiology, ecology) likely maintain host-associated differentiation.;Bed bugs are hematophagous pests, feeding only on blood. Hosts are located by the cues they emit, including CO2, body odors, and heat. Of these cues, heat is not well understood. In the third study, the effects of heat on bed bug activation, orientation, and feeding behavior were evaluated. Bed bugs oriented towards targets above ambient temperature, although positive thermotaxis was limited to short distances (< 3 cm). Furthermore, feeding was found to increase with blood temperature and this response was found to be relative to the ambient temperature. Taken together, these results indicate that heat is important in host location and feeding, but only over short distances.;Urban pests are often best known for the harm they cause and health risks they pose. Bed bugs and cockroaches are two of the most common and problematic indoor pests, each with their own challenges in regards to management and human health. In the fourth study, we evaluated bed bug infested homes for the presence and persistence of histamine. We found that histamine was present at significantly higher levels in bed bug infested homes than in un-infested homes. Furthermore, histamine persisted for three months after bed bugs were eradicated, suggesting it is highly stable in the indoor environment. These findings are the first to report histamine as an indoor environmental contaminant, and suggest bed bugs may pose a major health risk to humans.;In the fifth study, we evaluated the efficacy and health risks associated with total release foggers (TRFs) and compared results to a low-risk management strategy (gel baits). Total Release Foggers were found to be completely ineffective at controlling cockroaches in homes, while simultaneously producing large amounts of pesticide (pyrethroid) residues around the discharge site. Conversely, gel baits were found to be effective at reducing cockroach populations while only depositing small amounts of pesticides in targeted locations. The ineffectiveness of TRFs at reducing cockroach populations, their similar monetary cost compared to highly effective bait products, and the pesticide exposure risks associated with TRFs, call into question their utility in the marketplace. |
