Silk
Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. The silk farmers then heat the cocoons to kill them, leaving some to metamorphose into moths to breed the next generation of caterpillars. Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.
Samea multiplicalis
Caterpillars construct a silk cocoon inside of a leaf petiole on their host plant in order to pupate. Pupation lasts between four to ten days, with females developing faster than males. Time spent in this stage of development is not dependent on larval nutrition.
After they emerge from their cocoons, adult salvinia stem-borer moths spend the rest of their three- or four-week life span around their host plants, mating and laying eggs. Female moths lay an average of 150 eggs over the course of several days on the surfaces of host plant leaves or among hairs or leaflet structures. Moths prefer the host plant "P. stratiotes" for laying eggs due to its structure which provides abundant oviposition surfaces. Moths are not known to oviposit on "E. crassipes". Adults are tan with darker markings on both sets of wings and a wingspan of about 20 mm. Adult size is not significantly affected by larval nutrition levels, however insufficient nitrogen during larval development does lead to reduced egg production in female moths.