Sense organs on the ovipositor of Macrocentrus cingulum Brischke (Hymenoptera: Braconidae): their probable role in stinging, oviposition and host selection process

Parasitoid wasps from the insect order Hymenoptera can be deployed successfully as biological control agents for a number of pests, and have previously been introduced for the control of corn pest insect species from the Lepidopteran genus Ostrinia. Organs on the ovipositor of parasitoid wasps have mechanical and tactile senses that coordinate the complex movements of egg laying, and the ovipositor of Hymenopteran insects have evolved associated venom glands as part of their stinging defense. The ovipositor of parasitic wasps has evolved an additional function as a piercing organ that is required for the deposition of eggs within suitable host larvae. The morphology and ultrastructure of sense organs on the ovipositor and sheath of Macrocentrus cingulum Brischke (Hymenoptera: Braconidae) are described using scanning and transmission electron microscopy. Three types of sensilla trichodea were shown to be abundant on the outer sheath of the ovipositor, with types II and III being most distal, and the inner surface of the ovipositor covered with microtrichia, more densely near the apex. Sensilla coeloconica are distributed on both ventral and dorsal valves, while campaniform sensilla and secretory pores are only located on the dorsal valve. The olistheter-like interlocking mechanism, as well as the morphology of the ventral and dorsal valve tips and the ventral valve seal may be important in stinging, oviposition and in the host selection process. (C) 2013 The Authors. Published by Elsevier B.V. on behalf of Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. All rights reserved.