Morphology of Sensory Structures on the Antennae, Maxillary and Labial Palpi, Tarsi, and Ovipositor of Adult Callosobruchus maculatus and C. subinnotatus (Coleoptera: Bruchidae)

Abstract

The sensilla on the antennae, maxillary and labial palpi, tarsi and ovipositor of adult Callosobruchus maculatus (F.) and C. subinnotatus (Pic) were examined using light and scanning electron microscopy. Six types of antennal sensilla occur in both species. Type 1 are long and have longitudinal ridges and a conspicuous basal socket. These sensilla occur in rings at the distal margin of each antennal segment; the terminal segment bears 2 such rings. Type 2 sensilla are found on all segments and have a well developed basal socket and less conspicuous cuticular ridges. Type 3 sensilla are numerous and found only on flagellar segments. Type 4 sensilla are medium in length and stout. Types 5 and 6 sensilla are short, few, and are found along with type 4 sensilla in groups distally on the distal antennal segments. Types 1 and 2 are sensilla chaetica, type 3 are trichodea, and types 4, 5, and 6 are sensilla basiconica. Sexual dimorphism in numbers of antennal sensilla is observed. Maxillary and labial palps in both species have 3 types of sensilla. Two subtypes in type 3, fluted (3a) and blunt (3b), sensilla are observed in females of both species. Tarsi and ovipositor of both species have 3 types of sensilla each.