Role of Relatedness, Food Quality and Hunger on the Avoidance of Kin-Cannibalism in Higher Instar of Coccinellids

The study examined the kin-recognition ability in the third and fourth instars of two predatory ladybirds, Hippodamia variegata (Goeze) and Menochilus sexmaculatus (Fabricius), by investigating the impact of relatedness, food quality and hunger on the avoidance of kin-cannibalism. Higher instars of both species cannibalized more non-relative first instars than the relative ones, suggesting that they can distinguish kin and abstain from cannibalizing them. The frequency of cannibalism among these larvae increased when victims were fed on dissimilar and unsuitable diets compared to those fed on the same diet as the cannibals. Cannibalistic tendencies were delayed when victims were fed on the same and appropriate diet. Fourth instars of both species had greater encounters with victims whose diets differed. Hungrier larvae of both species had more encounters and incidences of cannibalism with a shorter latency period than their satiated counterparts. It is inferred that hunger, lack of access to natural food, and challenges during molting or pupation instigate ladybird instars to engage in cannibalism. Nevertheless, when relatives are presented as food, the frequency of larval cannibalism decreases. The rate of cannibalism was higher in M . sexmaculatus compared to H . variegata , as the former is a more aggressive predator.