Effect of behavioral conditions on silk characteristics in the Indian meal moth (Plodia interpunctella)

Lepidopteran silks are produced during the larval stage and are used for
mobility and protection from predators, parasitoids, and pathogens. Our
knowledge of silk structure and production in Lepidoptera is based largely
on the biology of the domesticated silkworm moth (Bombyx mori), but recent
comparative evidence suggests that silk production and structure vary
widely across moth taxa. Some species like the Indian meal moth (Plodia
interpunctella) are becoming important biological models to study silk for
its potential application to materials science and medicine, but many
aspects of silk production in this species remain unknown. Here we
characterize physical changes in the silk of P. interpunctella by
measuring the width of wandering and pupal silk strands and find that
pupal silk is significantly thicker than the latter.  We then
report individual variation in pupal silk production in our lab-reared
colony with a very small number of individuals forgoing pupal silk
(< 4%) and find that overcrowding had no effect on this, whereas
exposure to elevated temperatures reduced rates of pupal silk production.