MORPHOMETRIC OVERVIEW AND SEXUAL DIMORPHISM OF THE SUBFAMILY BRUCHINAE (COLEOPTERA: CHRYSOMELIDAE) USING SAMPLES COLLECTED FROM SAMARU ZARIA, NIGERIA.

Abstract

Callosobruchus maculatus, C. subinnotatus, Bruchidius. artrolineatus and Caryedon serratus are the most common members of the subfamily Bruchinae found in Zaria. They were obtained from godowns in Samaru markets or cultured from host commodity infested with either eggs or larvae/pupae of the insects. Measurement of the major diagnostic features of the subfamily Bruchinae was illustrated and a brief description of specific observable variables and sexual dimorphism of these insects was also carried out in J.C. Deeming Insect Museum, Institute for Agricultural Research, Ahmadu Bello University Zaria. A total of twenty seven characters were used comprising of eleven measurable variables, nine explanatory variables and seven ratios. A handheld digitalized MiScope microscope (40-140x magnification) was used to capture photographs and made measurements of major measurable diagnostic traits of the subfamily Bruchinae. These insects are relatively small, variable in colouration and often alike leading to confusion in their identification. This paper elucidates the major morphological characteristics of the subfamily Bruchinae to ease their early detection, accurate identification and characterization being sine qua non for the adoption of effective management strategies. Accurate identification is also a prerequisite to World Trade Organizations (WTO) negotiations regarding the presence or absence of pests in any commodity for international transactions.