information:extraction
Beneficial insects

Even though some butterflies and moths affect the economy negatively, many species are a valuable economic resource. The most prominent example is that of the domesticated silkworm moth (Bombyx mori), the larvae of which make their cocoons out of silk, which can be spun into cloth. Silk is and has been an important economic resource throughout history. The species Bombyx mori has been domesticated to the point where it is completely dependent on mankind for survival. A number of wild moths such as Bombyx mandarina, and Antheraea species, besides others, provide commercially important silks.

The preference of the larvae of most lepidopteran species to feed on a single species or limited range of plants is used as a mechanism for biological control of weeds in place of herbicides. The pyralid cactus moth was introduced from Argentina to Australia, where it successfully suppressed millions of acres of prickly pear cactus. Another species of the Pyralidae, called the alligator weed stem borer (Arcola malloi), was used to control the aquatic plant known as alligator weed (Alternanthera philoxeroides) in conjunction with the alligator weed flea beetle; in this case, the two insects work in synergy and the weed rarely recovers.

Breeding butterflies and moths, or butterfly gardening /rearing, has become an ecologically viable process of introducing species into the ecosystem to benefit it. Butterfly ranching in Papua New Guinea permits nationals of that country to "farm" economically valuable insect species for the collectors market in an ecologically sustainable manner.