Meeting Abstract
The body temperature of small ectotherms such as insects is determined passively through interactions with their thermal environment as well as more actively through muscle contractions that can produce regional endothermy. Elevated temperatures facilitate digestion, reproduction, and locomotion. We examined a possible additional source of warming, namely blood feeding in the insect Rhodnius prolixus. Surface body temperatures of the insects were measured using a thermal camera (FLIR ThermaCAM B2). After blood feeding to repletion on a rabbit, the body temperatures of the insects (32.1±0.4C, mean±SE) were significantly elevated over the room temperature (22C) and over insects placed on the rabbit but not feeding (29.6±0.4C). The difference in temperature between a warmed bug removed from the host and room temperature declined 90% in 5.4 minutes (nymphs) and 7.8 minutes (adult males). Rhodnius are cryptic and thigmotropic, rapidly seeking cover if placed in the open. We placed Rhodnius in an open arena and measured running speed as they sought cover. With body temperatures equilibrated to room temperature, fed nymphs ran significantly more slowly (4.7±1.0 cm/s) than unfed ones (7.9±0.7 cm/s). When tested at the temperatures occurring after blood-feeding, fed nymphs increased their running speed significantly (10.9±0.8 cm/s). We obtained similar results with adult male Rhodnius. We conclude that blood feeding significantly elevates the body temperature of both nymphs and adults of Rhodnius prolixus. Following blood feeding, body temperature remains elevated for several minutes. The capacity of the insects to flee the host and return to safe hiding refuges is enhanced by this elevated body temperature. Supported by NSF grant IOS 0920683 to TJB.
