Structure and function of the male ventral organ in Onychiuroides granulosus (Collembola: Onychiuridae)

Abstract

On the ventral tube of males of Onychiuroides granulosus (Stach, 1934) there is a male ventral organ, which consists of two groups of four setae that are thickened, slightly fl attened and bent. All setae of the male ventral organ are inserted in a richly sculptured cuticle. At the base of each seta there are a few large cells (basal cells) that have large irregular nuclei that contain a large amount of heterochromatin. In the cytoplasm of the basal cells there are numerous mitochondria, ribosomes and a rich system of endoplasmic reticulum. The plasma membrane of the basal cells forms richly folded, deep invaginations, fi lled with a dense material, which also occurs in particular setae and on their surface. The present study indicates that the male ventral organ is secretory and does not confi rm its previously suggested sensory function.

Structure and functions of the ventral tube of the clover springtail Sminthurus viridis (Collembola: Sminthuridae)

“…The eversible vesicles were regarded as a “cleaning” organ to clean up the body, or as a sticky appendage to enable springtails to adhere to slippery surfaces 1,2 . The adhesive ventral tube may even help direct the springtail jump 22,23 . An experiment carried out with Sminthurus viridis suggests that the ventral tube is used for conveying droplets of water from the hairs of the body to the mouth 24 .…”