Influence of four cereal flours on the growth of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae)

Abstract

The influence of four cereals namely, flours of wheat (Triticum aestivum L.), millet (Pennisetum glaucum L.), sorghum (Sorghum bicolor (L.) Moench) and maize (Zea mays L.) on the growth and development of T. castaneum was investigated at ambient tropical laboratory conditions of 30±3˚C and relative humidity of 75±5%. The antinutrients, mineral profile and proximate compositions of the four flour types and their effects on the
developmental activity of the flour beetle were studied. Results showed that the moisture content of the cereal flours ranged from 7.64% in wheat to 9.24% in maize, while protein content ranged from 10.91% in millet to
17.23% in wheat flour and the ash content in the flours ranged from 1.05% in maize to 2.59% in millet. However, the four cereal flours had sufficient nutrients to support the growth of T. castaneum. Millet flour had the highest number of larvae (435.50±0.85) at 56-day post-infestation thus depicting millet flour as the most preferred flour type for oviposition and egg incubation; while the lowest (286.25±0.41) number of larvae was obtained in maize flour and it was significantly lower (p≤ 0.05) than the number of emerging larvae in other flour types. The highest number of pupae was recorded in millet (387.50±0.65) and lowest in maize flour (312.25±0.65). The highest number of emergent adult Triboliumb was recorded in millet (357.00±0.41) and lowest in maize (268.25±0.65). Host preference (choice and no-choice) studies revealed millet flour as the most preferred food and maize flour as the least preferred. Based on the flour colour, anti-nutrient composition and population of the immature forms of the flour beetle, maize flour was the most unsuitable food source, while millet flour was the most susceptible to T. castaneum.

Keywords: Anti-Nutrients, Proximate Composition, Flour Colour, Cereal Flours, Rust-Red Flour Beetle, Tribolium castaneum.