Cannibalism in Spodoptera frugiperda larvae: Effects of food lack, host plants, and food distribution

The fall armyworm, Spodoptera frugiperda, is a highly polyphagous agricultural pest widely distributed around the world and causes severe crop yield loss. As a common phenomenon in many insects, cannibalism is also observed in the larvae of S. frugiperda. While the factors that affect this phenomenon in S. frugipreda larvae remain unclear and not quite systematic. In this study, the effects of three factors, including a lack of food supply, different host plants, and variation in food distribution, on the cannibalism of larvae from the third, fourth, and fifth instars of S. frugipreda were investigated. Our results suggest that a longer time without food supply, a non-preferred host plant, and simple food distribution could increase cannibalism. Our results not only provide critical information for the mass rearing of S. frugiperda larvae, but also offer preliminary support for further study on the mechanism of cannibalism in this pest.