Ultrastructure of the larval hemocytes of the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera : Gelechiidae)

Abstract

Based on ultrastructural characteristics, 5 types of hemocytes were observed in the hemolymph of mature fourth-instar larvae of the pink bollworm, Pectinophora gossypiella. These are prohemocytes, plasmatocytes, granular hemocytes, spherule cells, and oenocytoids. Prohemocytes are relatively small and infrequent, with simple cellular organization. Plasmatocytes are pleomorphic, and the 2 kinds most frequently noticed are spindle-shaped cells and ovoid cells, the latter with a large number of pseudopodial-ike extensions. Granular hemocytes contain granules of different types and are involved mainly in phagocytosis. A progressive accumulation of lipid droplets by these cells gives rise to what are often reported as adipohemocytes. Spherule cells contain many spherules made up of a flocculent material that is synthesized by the rough endoplasmic reticulum and packaged in the Golgi apparatus. Oenocytoids possess bundles of microtubule-like structures interspersed with free ribosomes and few Golgi elements. Their function, like that of the spherule cells, is not clear although it is speculated that both types are the source of some blood proteins. Another hemocyte type reported as podocyte in an earlier study was not noticed in any of the preparations.