Morfologia do canal alimentar e do sistema reprodutor de Atopozelus opsimus Elkins,1954 (Hemiptera: Reduviidae)

Abstract

Atopozelus opsimus Elkins, 1954 (Hemiptera: Reduviidae) is a predator of important agricultural and forestry pests. It presents desirable characteristics in biological control programs, such as high reproductive rate, high survival during periods of scarcity of the target prey, easy adaptation to the environment, and voracity. The objective of this dissertation was to study the anatomy and histology of the midgut, male reproductive system, and ovaries of this assassin bug, in order to increase the knowledge of its biology and its effective application as a natural enemy in integrated pest management programs for forestry pests. The digestive tract and reproductive systems of females and males were dissected and examined as well as processed and analyzed with light microscopy. Atopozelus opsimus has the digestive tract divided into foregut, midgut with three ventricles (V1, V2, and V3), and hindgut, being equal between females and males. In the midgut, there is a predominance of digestive cells that are multifunctional, with different sites for absorption, digestion, storage, excretion, and secretion. The midgut of A. opsimus is similar to that of other phytophagous, hematophagous, and predatory Heteroptera, which suggests that diet has not been a selective pressure and reinforces the origin from a common ancestor. The female reproductive system of A. opsimus has a pair of telotrophic meroistic type ovaries with seven ovarioles each, and continuous production of oocytes; two lateral oviducts, one common oviduct, two yellow-colored spermathecae, a novel characteristic for Heteroptera, and a genital chamber. The male reproductive system has a pair of testes covered by a transparent peritoneal sheath, composed of seven testicular follicles (similar to the ancestral form) with continuous production of spermatozoa; two deferent ducts with yellow-colored seminal vesicles (described for the first time), a pair of ectadenia accessory glands, and an ejaculatory duct. The morphology of the midgut, male reproductive system, and ovaries of A. opsimus, described for the first time, may contribute to the literature of biology with fundamental data on this important predator.