Fine Structure of the Mouthparts in the Bark Beetle Ips acuminatus (Coleoptera: Curculionidae: Scolytinae)

Abstract

The beetles of the superfamily Curculionidae have a distinct snout which has mouthpart at its end and is used for boring holes. These beetles are mostly plant feeders and are economically important pests of crops. Evolutionally, this beetle has developed its effective drilling mouthpart enough to make galleries directly into the heartwood of the tree. Here we have analysed the fine structural aspects of its functional mouthpart in the bark beetle Ips acuminatus using the field emission scanning electron microscopy (FESEM) to understand the mechano‐dynamic characteristics. The mouthparts of this beetle consist of a labrum, a pair of mandibles, a pair of maxillae and the labium. The mouthparts of this bark beetle exhibit typical morphology of mycophagous coleopteran beetles and have those characteristics of chewing mouthparts that can excavate galleries in the hardwood. Both of maxillary and labial palpi have the functions of direct the food to the mouth and hold it while the mandibles chew the food. The distal ends of these palpi are flattened and have shovel‐like setae.