For years, chemical ecologist Dawn Luthe and her students wondered why fall
armyworm caterpillars (Spodoptera frugiperda) let piles of feces, known
as frass, accumulate on corn, trapped in the plant's cuplike whorls where the leaves join the stalk.
Bracovirus genes can be detected in the genomes of several species of butterfly and moth, including the famous Monarch (Danaus plexippus), the silkworm (Bombyx mori) and insect pests such
as the Fall
Armyworm (Spodoptera frugiperda) and the Beet
Armyworm (Spodoptera exigua).