Ascia is a genus of butterflies in the family Pieridae. It is monotypic, being represented by the single species Ascia monuste, commonly known as the great southern white, In this species the sexes may differ with the female being either light or dark colored. It is found from the Atlantic and Gulf coasts of the United States, and south to Argentina. It is migratory along the south-eastern coast of the United States, with strays to Maryland, Kansas, and Colorado.
Larvae have distinct body segments within which there appears to be four to six subsegments. They are purplish-green with two longitudinal, greenish-yellow stripes on each side and the dorsal side. When full-grown, they are approximately one and a quarter inches long. The wingspan in adults is 63–86 mm (2.5–3.4 in). Adults are on wing all year round in southern Texas, peninsular Florida and along the Gulf Coast.
A. monuste is a migrating species that moves in one direction within its life span and does not return. It breeds in Florida but sometimes migrates along the coast up to 160 km (99 mi) to breed in more suitable areas.
Life history
This species seeks out appropriate plant hosts for oviposition by detection of compounds called glucosinolates present in the family Brassicaceae. Adults appear to prefer to lay their eggs on certain areas of the plant. On kale leaves, for example, the preferred regions are the apical, medium and basal parts of the leaves. The average number of eggs laid is about 43 with as many as 245, being laid singly or in clusters. A. m. monuste has been observed feeding on the chorion soon after hatching as their first food, as well as larvae feeding on eggs. It has been suggested that this behavior provides them with extra protein. If a female oviposits on a plant already supporting conspecifics, cannibalism is more likely. Since they have a high growth rate and a non-regulated body temperature, herbivorous insects require a higher quantity of protein. It is questionable that...
