Sperm Structure in the Psocoptera

Abstract

An account is given of the ultrastructure of the sperm in Psocoptera. Three main types of sperm occur. Type one, in Suborder Trogiomorpha, is an uncoiled long sperm with a filamentous head and a flagellum containing two or three lateral ridges and two central tubules. Twenty three per cent of this type has two axonemes and four mitochondrial derivatives. The second type, in the Suborder Psocomorpha, lacks both central tubules and lateral ridges. Four per cent of this type contain biaxonemes and four mitochondrial derivatives. In the third type, in the Suborder Troctomorpha. 100% of the sperm have two axonemes and two mitochondrial derivatives. The possible function and the method of locomotion of these types are described. The similarity between sperm structure in the Psocoptera and in Anoplura and Mallophaga suggests a close phylogenetic relationship between the three orders. 1989 The Royal Swedish Academy of Sciences