Role of Ants as Ecological Agents in Post-Infestation Cleanup of Pulses in Storage Conditions

The pulse beetle (Callosobruchus chinensis L.), also known as the cowpea weevil, is a serious pest of stored legumes such as chickpeas, green gram, black gram, and lentils. This reddish-brown insect lays eggs directly on the surface of pulses, where larvae bore into the seeds upon hatching and complete their development inside, and the adults finally emerge out through the exit holes leaving the hollowed-out seeds. This internal feeding by both larvae and adults reduces the nutritional quality and market value of the grains. Owing to its short life cycle and high reproductive potential, C. chinensis can rapidly build up large populations under favourable storage conditions, leading to significant post-harvest losses. Experimental studies were carried out under field conditions to explore safe, cost-effective, and ecofriendly options for containing the damage caused by C. chinensis. Ants (Formica sp.) were studied as natural foragers to understand their role in removing pulse seeds infested with various life stages of the beetle and/or beetle carcasses. This study investigated the orientational responses of ants to infested and non-infested seeds of two pulse types: chana dal, and moong chilka. The preference of ants for infested seeds suggests an ecological role of ants through seed debris removal. Ants’ foraging response was higher in proportion to the level of infestation, indicating the influence of olfactory or chemical cues. This study aimed to investigate the interaction of ants with infested and non-infested grains which could assist in removing beetle-infested seeds and carcasses under natural field conditions, and to highlight their potential in post-infestation cleanup and waste minimization. The findings of this study support the hypothesis that ants may contribute to post-infestation sanitation and may have utility in low-input pest management systems for stored grains.