Wandering speed and time, and location for the pupation of fully-grown larvae of the Indian-meal moth, Plodia interpunctella H.

Abstract

When confined individually in plastic containers (3cm diameter and 5cm depth) with no carton shelters, diapause fully-grown larvae wandered for 36-48 hours at 25-26℃ before stopping and making cocoons. They crept at an average speed of 10cm/39.1±SD12.5(male)-33.0±SD6.7(female) seconds on a paper sheet at 19-20℃. This suggests that they could move more than 221m within the first 24 hours. Non-diapause fully-grown larvae wandered for 12-24 hours at 27℃, and their speed was 10cm/25.2±SD6.4(male)-22.6±
SD3.8(female) seconds, also suggesting their movement of more than 171m for the first 12 hours. Provided with a piece of carton (1cm×1cm) as a shelter in each container, both the types of fully-grown larvae quickly entered the carton shelters (within 3-24 hours), without wandering so long. Extended lighting in every evening induced diapause larvae to pupate quickly when they had no shelters, while the diapause was hardly broken when the larvae could get into the shelters as well as in the case where the containers were kept in darkness. Both the types of fully-grown larvae tended to climb upwards, but showed stronger negative phototaxis.