Salvinia Stem Borer Moth

Samea multiplicalis was first observed in Brazil in 1854, and has since been documented across the southeastern United States, as far west as Louisiana. This region constitutes its native range. In 1981, the moth was introduced in Australia as a potential method of biological control of the water fern, S. molesta. It is now common throughout Queensland and New South Wales. In Australia, it has been found to thrive in tropical climates, with slower growth and dispersal in more temperate climates.

Often, groups of larvae display cooperative behavior when they feed in groups. They collectively construct a silk canopy over their feeding site while they eat, expanding it as they exhaust their current site and move on to new areas of their host plant. This behavior offers protection from predation, decreasing larval mortality.

Nitrogen is very important nutrient for larval development, especially during the first two instars, so larvae prefer food plants with higher nitrogen content. Higher nitrogen intake correlates with larger larval biomass and faster development, both of which are favored because they decrease larval vulnerability to predation. Additionally, a lack of sufficient nitrogen intake during early development leads to decreased ability to digest and utilize food throughout the rest of the insect's life.