Spermatozoa of Saldid bugs (Insecta, Hemiptera, Leptopodomorpha)

Spermatozoa from two species of the shore bugs (hemipteran family Saldidae) have been examined ultrastructurally in thin-sectioned and freeze-fracture replicated material with the aim of finding out whether they conform to the pattern that is characteristic of hemipteran spermatozoa. The two characters that previously have been found to probably be typical for hemipteran spermatozoa were present, i.e., bridges between the two mitochondrial derivatives and the axonemal microtubules 1 and 5 and complex crystals within the mitochondrial derivatives. In other respects the sperm ultrastructure differed: the acrosome was seen to form a large, flattened disc surmounted on an otherwise slender sperm body and the nucleus to be an elongated rod that runs parallel to the axoneme and the mitochondrial derivatives for most of their length. The acrosome was further characterized by an unusually low number of intramembrane particles; the only recognizable ones being some that form a double row of particles along the periphery of the acrosomal disc. It is speculated that the prominent acrosome cannot enter the micropyle and that the acrosomal reaction may already take place outside the micropyle.