Vija-Suarez Carlos Alberto, Ortiz Mario Iván, Molina Jorge
Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Universidad de los Andes, Carrera 1 # 18A-10, Bogotá, Colombia.
J Insect Physiol. 2017 Aug;101:31-38. doi: 10.1016/j.jinsphys.2017.06.011. Epub 2017 Jun 19.
The photonegative response to light stimulation in Rhodnius prolixus (Reduviidae, Triatominae) is modulated by compound eyes and ocelli. Screening pigments in the visual system have been shown to protect the cellular structures from the oxidative stress damage produced by blood ingestion and light stimulation. Red-eyed mutants of Rhodnius prolixus lack screening pigments in their compound eyes and ocelli and are exposed to more oxidative stress. Experiments with Rhodnius prolixus and Triatoma infestans red-eyed mutants reared from the first nymphal stage show damage in the retinas of the compound eyes and a decrease in photonegative responses due to light stimulation. Because ocelli are only present during the imaginal stages, we designed a group of experiments to assess the possible damage to the ocelli by oxidative stress mediated by blood ingestion in Rhodnius prolixus red-eyed mutants and wild-type insects. To test our hypothesis, we carried out behavioral experiments to evaluate the photonegative responses in adults exposed to different treatments, including coverage of either the compound eyes or ocelli, and different blood feeding regimens. Our results show that the ocelli in Rhodnius prolixus adults can modulate photonegative responses in red-eyed mutants better than the compound eyes can. In addition, a decrease in photonegative responses was evident when the red-eyed mutants were fed blood continuously for four weeks. Our results confirm that ocelli in Rhodnius prolixus can be considered a parallel pathway that intersects with information from the compound eyes regarding light stimulation and that their screening pigments play important roles in preventing the damage caused by oxidative stress due to blood ingestion.
红带锥蝽（猎蝽科，锥蝽亚科）对光刺激的负趋光反应受复眼和单眼调节。视觉系统中的遮光色素已被证明可保护细胞结构免受吸血和光刺激产生的氧化应激损伤。红带锥蝽的红眼突变体在其复眼和单眼中缺乏遮光色素，且面临更多的氧化应激。对从第一若虫阶段饲养的红带锥蝽和骚扰锥蝽红眼突变体进行的实验表明，复眼视网膜受损，且由于光刺激导致负趋光反应减弱。由于单眼仅在成虫阶段存在，我们设计了一组实验，以评估红带锥蝽红眼突变体和野生型昆虫因吸血介导的氧化应激对单眼可能造成的损害。为了验证我们的假设，我们进行了行为实验，以评估暴露于不同处理（包括覆盖复眼或单眼以及不同的吸血方案）的成虫的负趋光反应。我们的结果表明，红带锥蝽成虫的单眼比复眼能更好地调节红眼突变体的负趋光反应。此外，当红眼突变体连续四周喂食血液时，负趋光反应明显降低。我们的结果证实，红带锥蝽的单眼可被视为一条与来自复眼的关于光刺激的信息相交的平行通路，且其遮光色素在防止吸血引起的氧化应激造成的损害中起重要作用。
