Termite exocrine systems: a review of current knowledge

Abstract

Termite (Isoptera) social life comprises a coordinated and complex system, in which several activities are played by different castes such as mating, brood care, foraging, kinship recognition, social immunity, and nest defense. Such activities require specialized communication mediated mainly by semiochemicals, including pheromones (Costa-Leonardo & Haifig, 2014;Bagnères & Hanus, 2015). Such communication relies on the secretory activity of a wide set of exocrine glands located in different body parts, which may often be associated with the production of specific compounds for equally specific activities (Costa-Leonardo & Haifig, 2010a). On the other hand, the secretion of the same compounds might be observed among different glands, species, or even used for distinct activities, suggesting a parsimony and functional plasticity in chemical communication in termites (Robert et al., 2004;Costa-Leonardo et al., 2009a).Many termite exocrine glands produce pheromones, which are associated with chemical communication, whereas others produce defensive and antiseptic compounds (Rosengaus et al., 2004;Šobotník et al., 2010a). Such a defensive function is particularly well reported for the soldier caste and alate reproductives during swarming flights, occasions in which these individuals are vulnerable to massive predation (Lepage, 1991). Beyond their crucial role in nestmate interactions, exocrine glands in termites are involved in other physiological processes, including the production of digestive enzymes, synthesis of contents

Salivary gland substances of the arboreal termite Nasutitermes corniger induce worker aggregation and gnawing of food substrate

“…Social foraging in insects depends on individual behaviors triggered by positive and negative stimuli, which, according to their frequency and intensity, may amplify or attenuate different behaviors (Detrain & Deneubourg, 2008; Lehue & Detrain, 2020). In termites, social foraging behavior involves interactions among individuals of different castes and is essentially regulated by chemical signals released by nestmates and the food source (Costa‐Leonardo, 2002; Costa‐Leonardo et al, 2009; Traniello & Leuthold, 2000; Bagnères & Hanus, 2015; Leonhardt et al, 2016; Costa‐Leonardo et al, 2023).…”

Introduction to the special section on Biology of Termites

“…This special section of Entomologia Experimentalis et Applicata on termite biology reflects the latest achievements in the fields of termite research. Costa‐Leonardo et al (2023) provide an extensive review of the exocrine systems of termites. Termites possess a wide range of exocrine glands that not only allow them to digest tough substances, such as lignocellulose, but also serve crucial functions in communication, immunity and nest building.…”