Effect of adult weight and density on fecundity of Tenebrio molitor (Coleoptera: Tenebrionidae)

Abstract Newly emerged adults of Tenebrio molitor were grouped according to weight in 5 class groups. Groups of 5 females and 5 males from each class were placed in specially design boxes that allow hatching first instars to fall to a second box in the bottom. First instars were counted weekly for a period of 4 months. The second experiment consisted of groups of different number of adults (1:1 sex ratio) placed in the same type of boxes. First instars were counted weekly for a period of 1 month. Adult weight had no significant correlation with fecundity, but some class groups produced significantly more larvae than others. Groups ranging in weight from 70-79.99 mg and from 100-109.99 produced significantly more larvae than the rest of the weight classes. Adult density impacted significantly larvae production. Mean larvae produce per female decreased with increased adult density, but the optimal larvae production per box was obtained at an intermediate density. The optimal number of adults per box was 20 which correspond to a density of one adult per 714 mm2. Larvae production per box declined as adult density increased from the optimal.