Characterization of heat exposure‐associated escape behaviors and HSP gene expression in bed bugs (Cimex lectularius L.)

Abstract

BACKGROUND: Heat can be effective for bed bug elimination. However, in some cases bed bugs survive heat treatments. The objectives of this study were to determine the behavioral responses of bed bugs to rising harborage temperatures (23.0-49.0 °C) and identify which heat shock protein (HSP) genes are expressed after heat exposure. First, a custom-made copper arena and harborage were used to determine the escape behaviors of six bed bug populations. Next, HSP gene expression responses of select populations were determined after heat exposure using real time quantitative polymerase chain reaction (RT-qPCR).RESULTS: Analysis of the 25 min behavioral experiment data found that harborage top temperatures associated with 25%, 50% and 75% probabilities of bed bugs to flee the harborage did not differ significantly between populations. Also, the percentage of insects that escaped from heated areas and survived (4.0-12.0%) was not different between populations. However, when specific temperatures at which successful escapes occurred were statistically compared, the Poultry House population was found to flee the harborage at statistically higher temperatures (43.6 ± 0.5 °C) than others (40.5 ± 0.6-42.0 ± 0.7 °C). The RT-qPCR experiments revealed that the HSP70.1, HSP70.3, and Putative Small HSP genes were significantly up-regulated 15 min, 2, and 4 h post-heat exposure and decreased back to baseline levels by 24 h. CONCLUSIONS: This study shows that when harborage top temperatures approach 40.0-43.0 °C, bed bugs will disperse in search for cooler areas. This work implicates the HSP70.1, HSP70.3, and Putative Small HSP genes in heat induced stress recovery of bed bugs.

Lethal and sublethal heat-exposure of bed bugs (Cimex lectularius L.) causes alarm pheromone emission and elicits a movement response in nearby recipients

“…The release of AP in live bed bugs but not in frozen dead bed bugs indicates that insects must be alive prior to heat exposure to emit high concentrations of AP. This nding is similar to experiments which showed that live earthworms release AP in response to electrical shock 53 , but dead earthworms do not 55 .…”

“…Previous research has compared the heat repellency behavior of different bed bug populations when exposed to rising temperatures in their harborages 37 . These studies found that when bed bug hiding places are heated to 40 43 °C, they can ee and randomly locate unheated areas in close proximity 37 .…”

“…Previous research has compared the heat repellency behavior of different bed bug populations when exposed to rising temperatures in their harborages 37 . These studies found that when bed bug hiding places are heated to 40 43 °C, they can ee and randomly locate unheated areas in close proximity 37 . Therefore, it is likely that during a thermal treatment, bed bugs are stimulated to move by both heatinduced repellency 34,36,37,42,55 and AP emitted by conspeci cs, but how bed bugs react to both in combination is unknown.…”

“…Bed bugs are also repelled by other stimuli, such as high temperatures [34][35][36][37] and, if they manage to successfully escape lethally heated areas, pest management outcomes can be negatively impacted [38][39][40][41][42][43] .…”

Genome-Wide Identification and Analysis of the Heat-Shock Protein Gene Superfamily in Bemisia tabaci and Expression Pattern Analysis under Heat Shock

“…HSPs exist widely in insects and may play an important role in their heat adaptation, heat tolerance, and heat protection [ 10 , 11 ]. For instance, HSPs play important roles as molecular chaperones in promoting correct protein folding and preventing denatured protein aggregation [ 12 ]. Based on molecular weight and homology, HSPs constitute a supergene family that was divided into six families (small HSPs, HSP40, HSP60, HSP70, HSP90, and HSP100) [ 13 , 14 ].…”