Morphology of the male reproductive system, sperm ultrastructure and γ-irradiation of the red palm weevil Rhynchophorus ferrugineus Oliv. (Coleoptera: Dryophthoridae)

Abstract

In the present study we describe the morphology of the male reproductive apparatus and sperm ultrastructure of the red palm weevil - an invasive pest of several palm tree species - as well as the most important steps of spermatogenesis. The reproductive apparatus consists of a pair of testes (each formed by two lobes) a long tube-like accessory gland, a prostate gland and a small accessory gland. Characteristic features of the sperm are 90-100 μm total length, 10 μm nucleus, two mitochondrial derivatives, two accessory bodies, one well-developed puff-like structure and a typical insect 9+9+2 flagellar axoneme. One of the methods used for the biological control of pests is the Sterile Insect Technique (SIT), for the evaluation of which we make a preliminary comparison of the sperm ultrastructure of non-irradiated and irradiated weevils (at a dose of 80 Gray).

Keywords: Genital apparatus; Genital system; Insect spermatogenesis; Sterile insect technique (SIT); TEM.