Abstract Acanthoscelides obtectus males have 5 pairs of paragonia: the median, internal or external glands, the lateral glands, the tubular glands and the inferior glands. Their secretions are composed of proteins or mucopolysaccharids; lipids are absent. The tubular glands discharge their secretion into the lateral glands. The seminal vesicles also open into the lateral glands. The secretory activity of the paragonia changes during the life of males. The young males or the mating males, which produce many spermatophores, have glands with high and wide cells, but the lumens are reduced and empty. These cells have a basophilic cytoplasm (median, lateral or inferior glands) or a PAS-staining cytoplasm (tubular glands), and incorporate sodium radiosulfate (Na2S35O4) injected into the male abdomen. The 10-day-old, unmated males have secretions in the gland lumen and the epithelium becomes flat and stainless. These cells do not incorporate sodium radiosulfate, and their secretory activity is very low. Origins of these secretory activity variations are unknown.