Insect species whose larvae have high mobility, such as Ascia monuste (Godart), show a poor discriminatory oviposition behavior with respect to the quantity of food. Such behavior in A. monuste is influenced positively by the spatial and temporal abundance of kale (Brassica oleracea Var. acephala), its main host, in nature. A. monuste caterpillars frequently migrate in search of food to complete their development and even smaller larval clusters at about 20 individuals are not supported by the resources provided by a medium-size kale plant. Migration (dispersal) of 5th-instar larvae was necessary both in groups feeding on plants confined in cages and on plants growing in nature, and migration was successful when the plants were close to one another. The oviposition of A. monuste females on isolated plants was similar to the oviposition in clustered plants in nature. Ovipositing on isolated plants reduced the survival of immatures since larval migration was impaired by the absence of nearby host plants (experimental condition). Predation of larvae on the plant of origin was the major cause of A. monuste mortality in nature.
Brassica oleracea; egg-cluster; larval group; oviposition behavior; predation
