1.1.2.7 Ultrastructure of integumentary glands

Abstract

Publisher Summary This chapter discusses the structure of the integumentary glands in relation to their secretory function. Wax glands associated with the spiracles and spiracular furrows consists of spiracular setae and 5-1ocular wax glands. Spiracular setae strand curls downwards and inwards, giving the appearance of a feather. Each of 5-1ocular wax glands consists of a round, cuticular, sessile pore, whose diameter varies between 4–8 μm, and that has five circular loculi or micro-orifices, each with a diameter of about 0.2 μm, arranged in a circle. These pores are served by a gland system consisting of a common reservoir and eight glandular cells. Two types of wax gland are found ventrally associated with the area around the vulva, namely the tubular duct wax glands and the multilocular disc-pore wax glands. Both are involved in the production of the ovisac and are particularly abundant in species of the tribe Pulvinariini. The ovisac protrudes from the end of the abdomen. It is composed of a harder external part, which is made with the long filaments produced by the tubular ducts glands, and a looser inner part, which is made from the short curved filaments extruded through the multilocular disc–pore glands. Soft scale insects have evolved a series of external protective covers. The material needed for is secreted by a variety of dorsal wax glands, which completely cover the insects. In some cases, they are filamentous, woolly secretions, which completely cover the scale insect but the majority of soft scales secrete only a thin, amorphous wax in a series of layers or plates, thus increasing the thickness of the dorsum and reinforcing its resistance.