Dimorfismo de operários em Constrictotermes cyphergaster (ISOPTERA: TERMITIDAE): Polietismo e sobrevivência quando expostos a Aspergillus flavus

Abstract

The maintenance of termite colonies depends on several factors inherent to the way of life in society that these insects present, such as the division of labor between individuals and resistance to microorganisms that may compromise the colony. Many termites have polymorphic workers, whose characteristic may be associated with the division of tasks within the colony, in addition to life strategies that increase the survival of the caste. The dimorphism of the Constrictotermes cyphergaster termite workers is already known, however, the association with polyethism and the survival of the caste is not yet established. The present study aimed to observe if there is this interaction, and it was divided into two chapters: Chapter 1 - Influence of the morphological dimorphism on the polyethism of Constrictotermes cyphergaster (Isoptera: Termitidae) workers in the repair of nests, observing the repair activity of their nests in a caatinga area in the state of Paraíba. Fifteen nests were repaired within an hour, and workers were collected every five minutes, in cells other than the thermitic construction. The analyzed individuals were identified in small (SW) and large (LW) workers. SW individuals were more abundant during the repair activity in the sampled nests, with a decrease in the amount of LW until the end of the observation (1h). There was a reduction in the presence of both morphotypes with the increase in the volume of the nests. Our results, combined with field observations, show that the dimorphic workers of C. cyphergaster exhibit different behaviors in nest repair, and that SW is more engaged in this activity, while LW mimics the defense position of soldiers at the beginning of the activity; Chapter 2 - In this chapter, we saw the survival of dimorphic workers from this termite exposed to entomopathogenic fungus - here our objective was to observe the survival time of workers (SW and LW) to suspensions of the fungus Aspergillus flavus. The survival bioassays were performed with the two morphotypes treated separately and together. SW individuals had a longer average survival time in all suspensions tested in the two bioassays, while LW survival time increased when treated together with SW individuals. The results may support the hypothesis of the development of acquired immunity, since SW is more frequent on foraging trails and consequently more exposed to pathogens and that the survival of individuals within the colony may increase due to the lifestyle in society of these insects based on social immunity strategies.