Dynamics of Thermopreference in the Chagas Disease Vector <I>Panstrongylus megistus</I> (Hemiptera: Reduviidae)

Abstract

The thermopreference of resting P. megistus (Burmeister, 1834) adults was studied in a temperature gradient. We also determined the thermopreference for oviposition and ecdysis. Thermopreference of resting individuals depended on the feeding state of the insects. Results demonstrated an initial resting preference of approximately 290 degrees C, which gradually changed to 26-27 degrees C with increasing starvation. A daily variation in thermopreference was also observed with this species. The insects showed a daily maximum preference at the beginning of the dark phase, and a minimum preference during the first half of the light phase. Ecdysis took place all along the gradient, but exhibited a maximum frequency at 30 degrees C. Most eggs were found between 25 and 29 degrees C. Results are discussed in relation to the ecology of P. megistus as compared with other related species, and the existence of mechanisms of behavioral thermoregulation in the group.

Temperature preference in Rhodnius prolixus, effects and possible consequences

“…The same pattern of thermopreference, i.e. a daily variation, as well as a decrease in preferred temperature with increasing starvation was also observed in two other triatomines T. brasiliensis (Guarneri et al, 2003) and Panstrongylus megistus (Pires et al, 2002). This suggests that this thermopreference behaviour could be a generalised phenomenon in triatomines.…”

“…In a previous study Canals et al, (1997) found a thermopreference of 24.8 ± 5.8°C for Triatoma spinolai. Although we found similar values of thermopreference in R. prolixus, results are hard to compare due to differences in experimental design (see detailed discussion in Pires, et al 2002). When we compared thermopreference between male and female R. prolixus we found that females consistently preferred higher temperatures than males, (Figs.…”

“…They were placed in a communal jar for feeding and 24 h later they were weighed again. Because starvation level is a parameter that affects thermopreference in other ectothermic animals (Lazzari, 1991, Pires et al, 2002 were discarded.…”

“…The tendency to aggregate in this species should not be excluded from the assays, since it assures us that the strong individual thigmotaxis, also characteristic in this species, is accounted for. Since previous studies tested thermopreference in other triatomines with groups of insects (Lazzari, 1991, Canals et al, 1997, Pires et al, 2002, Guarneri et al, 2003 results can be easily compared between studies. The positions of the insects were recorded by means of an infrared-sensitive video camera, which had its own illumination system composed of 6 IR light emitting diodes (LED's) (900 nm) and 4 extra pairs of IR-LED's placed at each corner of the arena in order to provide homogeneous illumination.…”

Relationship Between Behavior and Physiology in an Invasive Pest Species: Oviposition Site Selection and Temperature-Dependent Development of the Oriental Fruit Moth (Lepidoptera: Tortricidae)

“…In the current study, oriental fruit moth females preferred oviposition sites culminating at a temperature of ϳ30ЊC as was clearly shown when the data from the temperature gradient were plotted relative to the area of the different temperature zones in analogy to a recent study by Kü hrt et al (2006). This behavior parallels the preference for a distinct temperature range within a gradient reported for different hematophagous hemipterans (Pires et al 2002, Guarneri et al 2003, Schilman and Lazzari 2004 and for a detrivorous dipteran species (Fogleman 1979). However, in a lepidopteran species closely related to the oriental fruit moth, the codling moth C. pomonella, females preferred the highest available temperature for oviposition regardless of the temperature ranges offered in a similar trial set-up (Kü hrt et al 2006).…”