A study of the stomach contents of species of Leptonema revealed that diatoms were the most frequent food items. Green algae, mayflies, and midges were also in the diet (Oliveira and Froehlich, 1996).
Mating in this genus takes places with the male and female facing in opposite directions, touching only at the apex of the abdomen. Mating takes place on the lower surface of leaves of streamside plants.
The surfaces on adult Leptonema are strongly water-repellant, and even if dropped in a turbulent stream they remain dry (Oliveira and Froehlich, 1996).
The caddisfly shown here is consistent with Leptonema albovirens, a species common in Central America, but it is not possible to rule out similar species without genitalic examination.
Photo location: Cartago province, Costa Rica.
American Insects site