Influence of Temperature, Relative Humidity and Protein Content on the Growth and Development of Larvae of the Lesser Mealworm, Alphitobius diaperinus (Panzer)

Konstantina Kotsou,Marina Gourgouta,Georgia V Baliota,Christos G Athanassiou,Christos I Rumbos

doi:10.3390/su131911087

Abstract

The human population is rapidly growing, subsequently leading to an increase in food and protein demand. Therefore, alternative protein sources have to be evaluated as food and feed. Among the most promising alternative protein sources with significant advantages are insects. Nevertheless, insect rearing conditions have to be optimized prior to insect mass production. In the present study, using laboratory bioassays, we evaluated the effect of several biotic and abiotic factors on the development of the larvae of the lesser mealworm, Alphitobius diaperinus (Panzer). In the first series of bioassays, we investigated A. diaperinus larval growth at three temperatures (25, 30 and 32 °C) and two relative humidity (r.h.) levels (55 and 75%). Furthermore, in the second series of bioassays, the larval growth was assessed on wheat bran-based substrates with different percentages of yeast, i.e., 0%, 10%, 17.5%, 25%, 32.5% and 40%. According to our results, the temperature was shown to be highly important for larval development, with A. diaperinus larvae performing better at the higher temperatures tested, i.e., 30 and 32 °C. In contrast, relative humidity did not have a significant effect on A. diaperinus growth, at least for the relative humidity levels tested. Finally, the increase in the percentage of yeast in the diet increased larval growth, development and survival. Our study aims to highlight the significance of several biotic and abiotic factors for the rearing of A. diaperinus larvae, providing parameters that can be further utilized in mass rearing protocols of this species.

Highlights

Insects have been an important component of the human diet in many tropical countries around the world [1]
The average larval weight and survival of A. diaperinus larvae grown at the different combinations of temperature and r.h. levels are presented in Figures 1 and 2, respectively
feed conversion ratio (FCR) and the total insect biomass were significantly affected by temperature, but not by relative humidity and their associated interaction, whereas SGR was significantly affected by both main effects, but not by their interaction (Table 1)

Summary

Introduction

Insects have been an important component of the human diet in many tropical countries around the world [1]. They were never really integrated into the Western dietary patterns and they were rarely given any consideration as part of the sustainability and food security agendas of international organizations [2]. In recent years, the rapidly increasing demand for nutrient sources due to the high global population growth, along with the imperative need for more environmentally friendly and sustainable food practices and habits, eventually led to the re-evaluation of insects as an alternative nutrient source for human food and animal feed [2,3,4,5]. Apart from the use of insects as feed, recently the larvae of the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae), have been approved by the European Food Safety Authority (EFSA) as food for human consumption [8]

Objectives

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Results

Conclusion