The Effect of a Eugregarine Gregarina polymorpha (Hammerschmidt) on the Mealworm Larva of Tenebrio molitor (L.)

SYNOPSIS. The larva of the beetle Tenebrio molitor (Coleoptera, Tenebrionidae), commonly referred to as the mealworm, harbors considerable numbers of gregarines in its midgut. These are not necessary for normal growth, nor do they prolong the life of larvae grown under optimal conditions of temperature, relative humidity and diet. When the larvae were grown under optimal conditions there was no significant difference between the length of larval life or the final pupal weight of mealworms harboring gregarines when compared with mealworms which had been reared free from gregarines. This applied both to infected and non‐infected larvae grown singly and in communal cultures. When, however, larvae were grown on a sub‐optimal diet, the gregarines had a considerable effect on the final pupal weight and the ability of the larva to complete development.