Influence of crate size, oviposition time, number of adults and cannibalism on the reproduction of Tenebrio molitor

Abstract

In an industrialised mealworm farm it is important to maximise the production and to know the number of mealworms in each container as early as possible in a fast and reliable way. Two experiments were performed. The first experiment assessed the influence of the number of beetles, crate surface area and oviposition time on the number produced mealworms. A full factorial design was used with 11 beetle densities (between 2.3-300 mg beetles/cm2), 5 oviposition times (from 1-14 days) and 4 different crate sizes (between 250-2,000 cm2). In the second experiment, the influence of cannibalism on the number of produced mealworms was assessed via an alternative oviposition method that prohibited cannibalism. Multiple linear regression was used to model the results. The results indicate that the number of beetles, oviposition time and surface area could predict the number of produced mealworms well. An increase in one of the three parameters increased the number of produced mealworms without reaching an optimum. Furthermore, the number of beetles and the oviposition time can be combined in one parameter, beetledays with minimal loss of predictive power of the model. Nevertheless, the number of produced mealworms per female did decline rapidly with increasing oviposition time and density. The latter is, at least in part, due to cannibalism, as the second experiment indicates that the density effect is almost eliminated when the beetles are unable to reach their eggs. In conclusion, this study indicates that it is possible to construct a formula that can be used to a priori determine the final number of produced mealworms based on the number of beetles, surface area and oviposition time and that cannibalism can greatly reduce the number of produced mealworms. Reducing cannibalism can greatly increase the efficiency and therefore production of a mealworm farm.