Electrophysiological detection of visible wavelengths of artificial lights inducing take-off in adults of Rhodnius prolixus (Hemiptera: Triatominae)

Abstract

Rhodnius prolixus is the most important vector of Trypanosoma cruzi in the northern part of South America. The compound eyes in adults of R. prolixus are involved in the nocturnal flight dispersion from sylvatic environments into human dwellings. During this behavior, the artificial lights play an important role in attracting R. prolixus; however, it is still not clear whether the compound eyes of this species use different visible wavelengths as a cue during active dispersion. We applied electrophysiological (electroretinography or ERG) and behavioral (take-off) experiments in a controlled laboratory setting to determine the spectral sensitivity of the compound eyes and the attraction of R. prolixus adults to discrete visible wavelengths. For the ERG experiments, flashes of 300 ms at wavelengths ranging between 350 and 700 nm at a constant intensity of 3.4 µW/cm 2 were tested after adaptation to darkness and to blue and yellow lights. For the behavioral experiments, the adults were exposed to nine visible wavelengths at three different intensities, and their direction of take-off in an experimental arena was established with circular statistics. The ERG results showed peaks of spectral sensitivity at 470–490 nm and 520–550 nm in adults, while behavioral experiments showed attractions to blue, green and red lights, depending on the intensity of the light stimuli. The electrophysiological and behavioral results confirm that R. prolixus adults can detect certain wavelengths in the visible spectrum of light and be attracted to them during take-off.

Spectral sensitivity of the compound eyes and behavioral attraction to light stimuli with different intensities and wavelengths in Lucilia sericata (Meigen, 1826) from Colombia

“…Using electrophysiological studies, we confirmed the presence of two photoreceptors, one for blue (450 nm) and the other for green (510-530 nm) in L. sericata from Colombia. The sensitivity observed in the violet range (400 nm) after selective adaptation experiments (Figure 3 Besides, the ranges of sensitivity measured for L. sericata adults from Colombia are similar to those reported for other populations (McFadden & Hans, 2019) and also for other diurnal and nocturnal insects with the presence of receptors to blue, green, and UV, like Euglossa dilemma (Dexheimer et al, 2023), Rhodnius prolixus (Ortiz et al, 2023), Myzus persicae (Kirchner et al, 2005), Glossina sp (Steverding & Troscianko, 2004) and Arachnocampa luminosa (Meyer & Eguchi, 1984).…”