ORIENTATION AND DISPERSAL OF LATE-STAGE LARVAE OF PORTHETRIA DISPAR (LEPIDOPTERA: LYMANTRIIDAE)

Abstract

AbstractLate-stage gypsy moth larvae, Porthetria dispar (L.), orient by polarized light in woodland openings. Activity of larvae was greatest before 1030 h and after 1400 h Eastern Standard Time, when plane-polarized sky-light was stronger and ground surface temperatures more moderate than during midday. Larvae in the opening were attracted to vertical objects up to 3 m distant at cardinal points closest to their path of orientation but much less to the cardinal points furthest away. Most larvae move in a north to northeast or south to southwest direction at abroad angle to the direction of the sun’s rays.