Efecto del estrés fisiológico en dos especies de hormigas (Hymenoptera: Formicidae) propias de cafetales de sol y de sombra, en condiciones de laboratorio

Abstract

= Effect of the physiological stress in two species of ants (Formicidae) that inhabit coffee plantations with and without shade. Using temperature as an indicator of microclimatic fluctuation, the behavior of Tetramorium simillimum, exclusive to sun plantations, and of Paratrechina steinheili, abundant but not exclusive to shade plantations, were analyzed in 2 thermal fluctuation tests (17 degrees-C & 32 degrees-C), & one thermal shock test (12 degrees-C & 35 degrees-C) in an environmental chamber. Control colonies were maintained at constant temperature (24 1 degrees-C). Ant activity outside the nest, foraging, & mortality were evaluated. In the first two tests, P. steinheili exhibited a relatively lower mortality than T. simillimum. In both cases, the colonies submitted to stress in the environmental chamber lost more workers than controls. In the thermal shock test, an increase in P. steinheili mortality was found, but it did not exceed that of T. simillimum.