Oviposition Behaviour of Pulse Beetle (Callosobruchus chinensis L.) on Different Stored Pulses

Adult female Pulse beetles, Callosobruchus chinensis L. use sensory receptors to detect host seed properties like texture, chemical composition and size for oviposition. Seed characteristics viz. size, texture and chemical cues significantly affect oviposition success and larval development. Perceiving these factors is crucial for managing infestations and reducing damage to stored pulses.

Oviposition behaviour was studied over two consecutive generations during 2022–23, using five stored pulses (chickpea, cowpea, lentil, pea and kidney bean) based on seed size, texture and shape.

The longest oviposition duration was observed on cowpea, followed by kidney bean, while the shortest period on lentil. The highest number of eggs were laid on the larger-sized kidney bean seeds, followed by cowpea. The pulse beetles showed a preference for larger seeds with a smooth seed coat, over rough-textured seeds and kidney-shaped pulses for oviposition. Number of eggs laid increased with increase in seed size. Thus, the higher egg counts on kidney bean and cowpea seeds can be attributed to their larger size, smoother texture and kidney-shape. Oviposition duration and fecundity were higher in second generation in all the types of pulse seeds except kidney beans where larval development couldn't take place in first generation.