Abstract
Although 13 exocrine glands have been located in wasps of the genus Polistes, and 12 in Mischocyttarus (Landolt and Akre, 1979), their morphology and functions have been little studied. Recently, however, the sternal gland on the sixth gastral (terminal) segment of females of these wasps has attracted attention because its secretion is repugnant to some species of ants. Female wasps rub the secretion onto the nest petiole, thus forming a chemical barrier against predatory ants (Jeanne, 1970; Hermann and Dirks, 1974; Turillazzi and Ugolini, 1978, 1979; Post, 1980).Close to the anterior margin ofthe sternite is a hyaline area covered with a tuft of long hairs (‘sternal brush’) (van der Vecht, 1968). In Polistes a cluster of gland cells underlies the cuticle on each side of the sternal brush (Landolt and Akre, 1979; Turillazzi, 1979). Ducts lead from the gland cells to the cuticular surface within the sternal brush. A smaller number of gland cells also occurs in a band along the anterior margin of the fifth gastral sternite (Hermann and Dirks, 1974; Turillazzi, 1979).We undertook the present study to determine the presence of these glands in Polistes fuscatus (F.), a temperate zone species, and in P. canadensis (L.), a tropical species, and to compare the size and morphology of the glands in these species with those in congeners previously investigated by Hermann and Dirks (1974) and Turillazzi (1979)