Feel the Heat: Activation, Orientation, and Feeding Responses of Bed Bugs (Cimex lectularius) to Different Temperatures

Bed Bug host location is poorly understood.  Of the primary host cues known to attract bed bugs (CO₂, odors, heat), heat has received little attention independent of the other cues.  Therefore, we evaluated the effects of temperature on bed bug activation, orientation, and feeding for temperatures ranging from 23-48°C (in 5°C increments).  To assess activation, the behavioral responses of individual quiescent bed bugs were recorded following the introduction of a heat coil into the arena.  To assess orientation, individual bed bugs were introduced into an arena already containing a heat coil and their behavior was recorded.  To assess feeding, individual bed bugs were offered blood in artificial feeders and the number fed was recorded.  Overall, temperatures <38°C resulted in significantly slower activation (time to initiate movement) and orientation (time to reach heat coil), but response times were not significantly different at temperatures >38°C.  Bed bug feeding responses increased linearly with temperature up to 38°C, remained constant at 43°C, and dropped significantly at 48°C.  These results provide the first measurements of bed bug activation, orientation, and feeding in response to different temperatures, estimate the distance at which bed bugs can detect hotter objects, and should assist in improving bed bug management.