Ultrastructural characterization of spermatozoa in euglossine bees (Hymenoptera, Apidae, Apinae)

摘要

Euglossine spermatozoa are the longest described to date for the Hymenoptera. This cell includes a head and a flagellar region In transverse sections, the acrosome is circular at the tip but has an oval contour along most of its length. The perforatorium penetrates into a deep cavity in the nuclear tip. The flagellum consists in an axoneme, a pair of mitochondrial derivatives, a centriolar adjunct and a pair of accessory bodies. The axoneme has a 9+9+2 microtubule pattern which becomes gradually disorganized in the final portion, with the central microtubules and the nine doublets terminating simultaneously, followed by the accessory micro-tubules. The mitochondrial derivatives are asymmetric both in length and diameter. Sectioned transver sally, the derivatives are ellipsoidal or have a pear shape. The larger one has a more obvious paracrystalline region The centriolar adjunct begins at the nuclear base and extends parallel to the axoneme until it encounters the smaller mitochondrial derivative, on which it fits, making a concave groove. In addition to these consistent euglossine features, species-specific differences that might be useful in phylogenetic work on the group are also noted.