Determination of the Settling Velocity and Its Significance to Larval Dispersal of the Gypsy Moth (Lepidoptera: Lymantriidae)

Abstract

The settling velocity of newly hatched gypsy moth, L. dispar (L.), 1st instars was determined to range from 41-117 cm/s. Settling velocity is proportional to the weight of the unfed larvae and is modified by attached silk. A 90 cm length of silk causes a 30-50% reduction in the settling velocity of larvae. The role of settling velocity in the passive dispersal of gypsy moth larvae is discussed in the context of current theories which relate the dispersability of larvae to qualitative differences among populations.