Aspectos imunológicos e morfologia do canal alimentar de operários de Nasutitermes coxipoensis (Holmgren) (Isoptera:Termitidae)

Abstract

About 10% of the termites’ species have been pointed as agent of some type of damage to the plants. Due to the diversity of food utilization of termites, the characteristics of the digestive tract of the workers and pseudo-workers can be used in systematics and filogenia of these insectes. A control methods of termites is the use of entomopathogenic fungi. Aspects regarding the immunologic response of termites triggered by pathogens invasions, however, remain scarce especially related to the immune reactions deflagrated by the hemocytes. Thus this research focused the following objectives: 1. to identify and to characterize the hemocytes morphology of Nasutitermes coxipoensis (Holmgren) worker´s cast; 2. to generate information about the immunologic reactions of hemocytes when challenged by Metarhizium anisopliae (Metsch.) Sorokin in N. coxipoensis workers and, 3. to describe the histology of workers digestive tractaiming to contribute with support information for systematics of termites. Analysis in light and electronics microscopy of the hemocytes typified the presence of the following cells: Plamatocytes (PL), Granulocytes (GR), Spherulocytes (ES), Prohemocytes (PR), Adipohemocytes (AD) and, Eonocytoids (OE). Among the concentrations from 1x10? to 1x107 conidia/mL of M. anisopliae, the highest concentration 107 conidia/mL was the most efficient with LT50 of 1.62 days. Under this concentration verified greatest frequency of Plamatocytes and Granulocytes in the hemolymph collected during the intervals of from 24 to 72h after application. The hemocitarydynamics during the intervals of 24h, 48h, and 72h after application exhibited significant reduction in Plamatocytes and increasing in Granulocytes. Despite of variation on cell counting was not notified any morphological alterations in the cells. The use of termites spraying as treatment method with 1x107 conidia/mL, in laboratory, triggered the defense mechanisms of N. coxipoensis. The histology of the digestive tract of the workers, in general, exhibited similar characteristics to those observed in other species of termites. Exceptions, however, were identified in the morphology of the epithelial cells regarding the types, number and displaying of these cells in the region of stomodeum as well as the existence of the peritrophic membrane in the region of midgut. Thus these characteristics can be used as criteria for the differentiation among the species of termites of the genus Nasutitermes.