Bagworm moth larvae spend most of their lives inside a “bag” or case. Made of silk and covered with bits of plant material and other debris, they carry it around as they feed and will enlarge it as they grow. Larvae of some species eat lichen, while others prefer green leaves of a specific deciduous or coniferous tree. When it comes time to molt they will fasten their bag to their food plant and push the old exoskeleton out through the top. Their droppings are also disposed of this way. When they are ready to pupate they fasten their case down one last time to a twig or other object. Males emerge winged and fly to waiting females… who are wingless or have wings reduced to tiny stubs. After mating, the female lays her yellowish eggs on or in the case and dies — or may even die with the eggs still inside her. Some species are parthenogenetic and skip the mating step altogether.  

Photo by: Glenn Marangelo on 7/6/21 near Florence, MT