Behavioural insights into cannibalism of fall armyworm, Spodoptera frugiperda (J.E. Smith) at Raipur, Chhattisgarh

Abstract

Fall armyworm, Spodoptera frugiperda is an economically important pest worldwide and larval cannibalism is documented as one of its significant behaviours under field and laboratory conditions. Conducted at Entomology laboratory, Department of Entomology College of Agriculture, IGKV, Raipur (C.G.) during August to October, 2024. When the same larval instars were allowed for interaction, there was less cannibalism compared to interaction between the combinations of different instars of larvae. A high rate of cannibalism was observed in the absence of food. Cannibalism absent in 1st instar larvae whereas 62 percent cannibalism recorded in case of 2nd instar larvae compared to 28.01 and 22 percent in 3rd instar and 4th instar larvae respectively. Cannibalism progressively increased in combinations involving different-aged larvae. A highest cannibalism was observed 100 percent in 1st to 5th instar combination followed by 96 percent in 1st to 4th instar combination, 77.33 percent in 1st to 3rd instar combination. Because of cannibalism increased as the developmental disparity between individuals grew, potentially due to heightened resource competition and the superior predatory efficiency of more developed larvae.