Styrofoam boxes used for shipping mass-reared beneficial arthropods: Internal temperature responds rapidly to ambient temperature

Styrofoam boxes are thought to provide protection for natural enemies by buffering changes in ambient temperature during shipment. Boxes (40×24×13 cm L/W/H; wall thickness 1.8 cm) from a commercial insectary, equipped with temperature loggers, were shipped back to the insectary where they were packed and returned by courier. Internal box temperature and ambient fluctuated in a synchronized manner, differing by <3°C and remaining above 20°C for most of the shipping period. Under controlled conditions, internal box temperature was not effectively regulated by a frozen gel pack, even when boxes were encased in cardboard. Styrofoam boxes of the type and size tested should be refrigerated during shipment.