The butterworm, the larva of the Chilean Moth (Chilecomadia moorei), is a unique invertebrate popular in the pet and bait trades. Its bright coloration and high nutritional value make it a frequent purchase for reptile owners and anglers. The transformation from this plump larva into its final adult form is a complex journey of metamorphosis. This journey is rarely completed outside of its native habitat.
Defining the Butterworm Larva
The butterworm is recognizable in its larval stage due to its smooth, plump body and bright orange or yellowish-gold color. These larvae typically reach 1.2 to 1.5 inches in length and are native exclusively to the central regions of Chile. In its natural environment, the caterpillar feeds on the leaves of the native Trevo shrub, which contributes to its unique coloration and nutrient profile. As a feeder insect, the butterworm offers high fat and calcium content, making it a nutritious, calorie-dense treat for many insectivorous pets.
The Process of Pupation
The transformation into the adult moth begins with pupation, the intermediate stage in complete metamorphosis. For this to occur naturally, the mature larva requires a suitable substrate, such as soil or leaf litter, and ambient temperatures between 75 and 85 degrees Fahrenheit. Under these conditions, the larva forms a pupal casing and begins the restructuring process. The pupal stage is relatively short for this species, lasting five days up to three weeks before the adult moth emerges.
The Adult Stage: The Chilean Moth
The final form of the butterworm is the Chilean Moth, Chilecomadia moorei. Unlike the brightly colored larva, the adult moth is a stout, hairy insect with a muted, mottled gray-brown coloration. Its appearance is typical of many nocturnal moths. The adult moth’s primary function is reproduction, and it does not possess functional mouthparts for feeding. Because its purpose is only to mate and lay eggs, the adult moth has an extremely short lifespan, typically lasting only a few days.
Commercial Rearing and Trade
Few people witness the butterworm complete its life cycle due to strict trade regulations. The Chilean Moth is not native to North America and is classified as a pest species, meaning its establishment could harm local agriculture. To prevent it from becoming an invasive species, all commercially imported butterworms from Chile must undergo a specialized quarantine treatment. This process involves low-dose gamma irradiation, which effectively sterilizes the larvae, rendering them incapable of pupating into adult moths. This measure ensures the butterworm remains a non-reproducing larva outside of its native country, explaining why the insect is nearly impossible to breed at home.