Cold sensitivity of last instarGalleria mellonellalarvae was investigated by measuring (1) the number of extra‐larval molts, (2) the number of larvae retaining ability to secrete silk, and (3) the number of larvae showing arrested development, after 2 h exposure to 0°C. Daily changes refer to the production of extra‐larval molts only, which are not generated by photoperiod. These variations result from (a) the time of day at which larvae molt from the penultimate into the last larval instar, (b) the sex of larvae, (c) the age of larvae at cooling, and (d) the time of day at which cooling stress was given.