Butterworms are insect larvae commonly recognized as fishing bait or a nutritious food source for pet reptiles and amphibians. These soft-bodied creatures originate from the dry, arid regions of Chile. While often encountered in their larval form, butterworms are not fully developed insects but rather a stage in a complete metamorphosis.
Understanding the Butterworm Larva
The butterworm is the larval stage of the Chilean Moth, Chilecomadia moorei. These caterpillars display a distinctive bright yellow-orange to reddish-yellow coloration. They measure between 1.25 to 1.5 inches (2 to 3 cm) in length and possess a unique, fruity scent. In their natural habitat in central Chile, these larvae feed exclusively on the leaves of the Trevo tree (Trevoa trinervis). Breeding butterworms in captivity outside of Chile is difficult due to their specialized diet and environmental needs, leading to their primary importation from their native country.
The Pupation Process
The butterworm undergoes complete metamorphosis, transitioning through four distinct life stages: egg, larva, pupa, and adult. Once the larva has consumed enough food and reached full size, it prepares for the pupal stage. During pupation, the larval body transforms, breaking down and reforming into the structures of the adult moth.
In natural conditions, this pupal stage lasts from 5 to 21 days, depending on environmental factors. However, commercially imported butterworms are often subjected to low-level irradiation before export from Chile. This process sterilizes the larvae and prevents them from pupating into adult moths, addressing concerns about the species becoming an invasive pest outside its native range. For those keeping butterworms as feeders, refrigeration at temperatures of 40 to 50 degrees Fahrenheit (4.4 to 10 degrees Celsius) is recommended. This cool environment slows their metabolism, pausing their development, allowing them to remain in their larval state for one to four months.
The Adult Chilean Moth
If allowed to complete its life cycle, the butterworm transforms into the adult Chilean Moth, Chilecomadia moorei. This moth belongs to the Cossidae family, also known as carpenter or leopard moths. As an adult, the primary purpose of the Chilean Moth is reproduction.
The adult moth emerges from the pupal casing to mate and lay eggs, typically on the leaves of the Trevo tree, thus restarting the life cycle. While specific detailed descriptions of the adult Chilecomadia moorei coloration are not widely available, moths in this family generally exhibit cryptic coloration, blending with their environment. The adult lifespan is short. In Chile, these moths and their larvae are a natural component of the ecosystem, but outside their native range, the species is regarded as a potential pest.