Anatomy of the Infective and Normal Third-Stage Juveniles of Neoaplectana carpocapsae Weiser (Steinernematidae: Nematoda)

Abstract

In a study of the fine structure of the infective and normal 3rd-stage juveniles of Neoaplectana carpocapsae, pronounced differences were found in the structure of the sensory organs, digestive tract, hypodermal chords, excretory system, and somatic musculature. Whereas the normal juvenile of this entomogenous nematode is an active feeding stage, the digestive tract of the infective juvenile is nonfunctional and the tissues in general have a condensed appearance. Cells of Achromobacter nematophilus were present in the intestinal lumen of both stages. The amphids and somatic muscles were more highly developed in the infective juvenile and are probably important in locating new hosts. Specialized types of cell organelles, consisting of tubular profiles in the lateral excretory canals and lamellae around the ventral excretory tube, were found associated with the excretory system of the normal juvenile.