Short-range responses of Triatoma rubida (Hemiptera:Reduviidae) to heat

The haematophagous bug Triatoma rubida is a locally occurring species of kissing bug and one that has been marked as a potential vector for transmission of Chagas disease within the U.S. Our study aims to characterize their response to various temperatures (25, 32, 36, 40, 45, and 55°C) and various humidities (5, 30, 60, and 90% RH). In both experiments, we used a video tracking system to characterize the behavior of the bug during the trial. To test for responses to heat, we constructed an arena with a ceramic resistor mounted in the center; concentric zones for analysis were set at distances from the source (4.5, 9.1, 13.7, and 18.25 cm). For humidity, we used a four-arm olfactometer and an improvised humidity control method. When compared to the control (25°C), bugs were about twice as likely to visit the source at 40 and 45°C and spent about twice as much time within 4.5 cm from the source at 36, 40, and 45°C, an effect which was lost at 55°C. Bugs spent the most time near the 30% RH treatment and chose it the most. This data supports our hypothesis that T. rubida responds preferentially to certain temperatures and humidities.

Keywords:  Kissing bug, short range responses, heat, relative humidity, host seeking behavior, video tracking system