Análise morfológica e ultraestrutural do canal alimentar de Chrysoperla externa (Hagen) expostas ao thiamethoxam e chlorantraniliprole

Abstract

The Chrysperla externa (Hagen, 1861) has traits that allow it to be included among the natural enemies indicated for biological control programs. The larvae are capable of preying on a large variety of prey, such as aphids, mealybugs, whitefly, eggs of small lepidopteran caterpillars and mites. The pres ervation of green lacewing in agricultural ecosystems must be considered when establishing integrated pest management programs. This will depend on the compatibility with other control methods, especially those related to the use of insecticides. The food channel is the focus of many researches, since the use of insecticide can induce several changes in the digestive system of natural enemies. Insecticides thiamethoxam and chlorantraniliprole are used for cultures with the occurrence of beneficial insects. Thus, this work aimed at evaluating the morphology and ultrastructure of the food channel of C. externa larvae and adults exposed to sub-lethal doses of thiamethoxam and chlorantraniliprole. In the treatments, we used the concentrations (CL50) of 0.59 ng i.a/µL of thiamethoxam and 19.62 ng i.a/µL of chlorantraniliprole, by ingestion exposure. We observed no cytomorphological changes in relation to control in the analyses conducted after ingestion of the insecticides. The results showed no regional morphologic differences in the mesentery epithelium, maintaining its typical regular structure with column digestive cells and nests of regenerative cells. No irregularities were verified in the striated edge, or damage to the peritrophic membrane of the midgut of the larvae or adults. Therefore, we conclude that insecticides thiamethoxam and chlorantraniprole, in the concentrations of 0.59 ng i.a/µL and 19.62 ng i.a/µL, respectively, caused no morphologic ou ultrastructural changes to the mesentery epithelium of C. externa larvae or adults.