The Bagworm Moth (Dahlica triquetrella) is native to Europe, but was introduced to North America around 1940. Some winged males occur in Europe, but the population in North America contains only wingless females. You might wonder how offspring are produced without males – the females reproduce through parthenogenesis, laying eggs without being fertilized by a male.
The caterpillars, which feed on lichen, algae, and moss, make and retreat into a silken bag to spend the winter – this is why they are called “bagworms”. The bag is covered with fine debris such as grains of sand and dead plant parts. The larvae pupate inside the bag and adult moths emerge in very early spring and deposit eggs into the bag they just emerged from. Their diet has to be supplemented by dead insects for development to be successful. The adults don’t feed and probably only live three or four days.