Structure and function of feeding in larvae of Nebria (Coleoptera: Carabidae)

Publisher Website
Google Scholar
Abstract
The larval head capsule and mouthparts of Nebria species are adapted for capturing prey which have rapid escape responses and for efficient fluid feeding. Larvae discover prey by tactile contact and capture them by impalement on their long, sickle-shaped mandibles. In capturing prey, the mandibles appear to act as a snap trap triggered by contact with four specialized nasale spines and (or) two hairs projecting from the lateral margins of the frontale into the space embraced by the mandibles. Larvae egest proteolytic enzymes onto captured prey and shred the prey's cuticle through action of the mandibles against a heavy ventral nasalar spine. A mastication cycle involves rotation of the food bolus and periodic squeezing to extract liquified body contents of the prey. Probable chemo- and mechano-sensilla suited to mediate feeding are distributed on the mouthparts. Liquid food is strained through hairs and acanthae of the preoral chamber while being drawn into the cibarium by contraction of powerful cibarial dilators. Cibarial constrictors are not present and food is forced into the pharynx by natural elasticity of the cibarial walls. Larval mouthparts are highly specialized for fluid feeding while those of adults of Nebria are adapted for consuming solid food.