Athanas Alexander Katoo* 1
The cowpea (pigeon pea) weevil, Callosobruchus maculatus (Fabricius) is a major pest of stored pulses, more specifically the cowpea and pigeon pea. This insect is of the order Coleoptera, Chrysomelidae family, and Bruchinae subfamily. Also referred to as the cowpea weevil or cowpea seed beetle, it is a global bug that results in considerable crop losses of stored legumes in the tropical and subtropical climates as noted by Akbar et al. (2022). Adult C. maculatus beetles are small in size and are usually between 2.5 to 3.5 millimetres in length (Magaji et al., 2020). They have a very unique brown fur with black and grey markings. Elytra (wing covers) are especially distinctive; they are coloured black with large spots also helping to identify the species. The insects are sexually dimorphic, where the females are slightly larger than the males. The antennae are grooved and are segmented into 11 different sections which is a distinct feature of the species (Salunkhe & Gaikwad, 2023).
Figure 1: Mature Male and Female Pigeon Pea Bruchid (Callosobruchus maculatus). Adapted from Ethan Estabrook, BCE-Research Associate at Insects Limited
2.0 Life Cycle of Callosobruchus maculatus
C. maculatus undergoes holometabolous development, characterized by complete metamorphosis through four distinct stages: These stages are the egg stage, larvae stage, pupal stage, and the adult stage (Salunkhe & Gaikwad, 2023). The overall development time depends on the environmental conditions in terms of temperature and humidity.
10.5281/zenodo.15085157