Temporary feeding inhibition caused by artificial abdominal distension in the bedbug, Cimex lectularius

Abdominal distension of haematophagous insects caused by ingested blood has been recognised as an important contributor to triggering meal termination, feeding inhibition and further susceptibility to host signals. Factors that regulate feeding behaviour of the common bedbug, Cimex lectularius, are poorly understood. By injecting air directly into the body cavity of virgin female C. lectularius we artificially induced abdominal distension without providing chemical cues of the blood meal and without applying gut distension. Body length increased to 138% after feeding and 147% after inflation. The early decline in body volume is similar in blood-fed bugs but after between 8 and 24 h became faster in inflated than fed bedbugs. Artificially inflated individuals remained feeding-inhibited at lower abdominal distensions than those that terminate blood ingestion (to ca. 135% initial body length, or up to about 5 h). Feeding activity resumed earlier in inflated than blood-fed bugs. These results suggest that artificial abdominal distension has an inhibitory effect on feeding but is not the sole mechanism in preventing further feeding.