The frontal weapon of the termite Armitermes euamignathus Silvestri (Isoptera, Termitidae, Nasutitermitinae)

Abstract

ABSTRACT. Frontal weapon is the term used to designate the apparatus consisting of frontal gland and assoc iated structures that participate in the chemical detense of termite sold iers. The ultrastructure of the frontal gland and the scanning mi croscopy of the so ldier head was investigated in the termite A/'lIlilermes ellolllignolhlls Silvestri, 190 I. Campan ifonTI sensi ll a was not observed but there were 80 to 100 sensOlY bristles around the frontal pore. The g landular epithelium shows only class I cell s according to the classification of NOIROT & QUENNEDEY ( 1974, 199 1). The glandul ar cells are characterized by apical microvilli, a basa l labyrinth and a large quantity of sl1100th endoplasmic reticulum which [onTIs dense zones throughout the cytoplasm. The secretion is concentrated mainly in the basal pole of the cell and consists of large lipid droplets. The secretory epithelium is covered by a thick apical cuticle composed of a thin outer epicuticie, a layer of epicuticular fil aments and a dense procuticle. The cytological results concerning the trontal pore showed a reduced cuticle and the presence of a subcuticular space where the lipid droplets are accumulated. The lack of class 3 cells and the presence of an intrinsic musculature are two anatomi cal feat ures of the A. ellomignoli1l1s frontal g land that w ill be impOltant in th e phylogenetic relationships of the Nasutiterm itinae.

Anatomy of the frontal gland and ultramorphology of the frontal tube in the soldier caste of species of Nasutitermitinae (Isoptera, Termitidae)

“…The morphological pattern shown by the frontal gland of Syntermes has already been described for soldiers of other species of Nasutitermitinae, such as Cornitermes and Armitermes (Costa-Leonardo, 1998, 2001Costa-Leonardo and De Salvo, 1987;Quennedey, 1984). This morphological pattern can be described as sac-shaped, lacking a glandular neck, and the associated musculature consists of short fibers that are not connected to the integument.…”

“…In these soldiers, known as nasutes, there is a rostrum that arises as a prolongation of the insect's head capsule. This nose might vary from a shallow cone open to a long tube, which corresponds to the frontal tube and has the function of expelling the secretion produced by the frontal gland (Costa-Leonardo, 1998, 2001Costa-Leonardo and Barsotti, 1996;Costa-Leonardo and De Salvo, 1987;Fontes, 1987). According to Kriston et al (1977), the soldier caste in the subfamily Nasutitermitinae is always peculiar and different from the other individuals of the colony, so much so that for Deligne et al (1981), this caste is the most specialized among all the castes of social insects.…”

Ultrastructural organization of the genital tracts in amphigonic females of Euceraphis betulae Koch (Aphididae: Calaphidinae)

“…Even if during our investigation we did not take into account the chemical nature of the secretion of the accessory glands and its specific function, nevertheless it is known that the presence of SER in cells with glandular activity, in species of different insect orders, is generally related to the biosynthesis of lipid components that would play many roles (Waku 1978;Foldi 1981;Hepburn et al 1991;Cassier and Lensky 1995;Osborn et al 1999;Costa-Leonardo 2001;Sturm 2002;Vieira et al 2012). In some Aphidoidea, in particular, these components, elaborated by some epidermal cells, seem to be involved in the production of wax that covers the body surface, making it waterproof and protecting the organism from predators and bacterial or fungal infections; this wax could also create a favourable microclimate for their survival (Smith 1999).…”

Adhesive Exocrine Glands in Insects: Morphology, Ultrastructure, and Adhesive Secretion

“…Diagrams of the ultrastructure of selected examples typical of adhesive epidermal glandular cell units occurring in insects. Adapted fromCosta-Leonardo (2001) and reproduced with permission. This cell possesses a deeply invaginated reservoir-like extracellular space bounded by a microvillus border.…”