Communication of leaf suitability by gregarious eastern tent caterpillars (Malacosoma americanum)

Abstract

ABSTRACT. 1. Previous work has shown that leaf age affects recruitment trail marking by eastern tent caterpillars (Malacosoma americanum Fabr.). Young leaves of host plants elicit trail marking to a greater degree than mature leaves.2. Experiments were conducted to establish the relationship between the differential behavioural responses of larvae to young and mature leaves and the suitability of foliage for larval growth and survival. Foliage of black cherry (Prunus serotina Ehrh.), a typical rosaceous host plant, was used for this comparison.3. Larvae preferred young leaves to mature leaves in choice tests, and marked more to young leaves than to mature leaves in no‐choice tests.4. Mature leaves supported adequate growth through two larval instars of rearing, but thereafter were unsuitable for growth. Larvae fed mature leaves had lower pupal weight, poorer survival, and grew less efficiently than larvae fed young leaves.5. The results support the hypothesis that the trail communication system of eastern tent caterpillars is an adaptation to efficiently locate leaves which are favourable for larval growth and survival.