Threshold temperatures and thermal requirements of black soldier fly Hermetia illucens: Implications for mass production.

Shaphan Yong Chia,Subramanian Sevgan,Chrysantus Mbi Tanga,Komi K M Fiaboe,Daisy Salifu,Sunday Ekesi,Joop J A Van Loon,Fathiya M Khamis,Samira A Mohamed,Marcel Dicke,Saliou Niassy,Patrizia Falabella

doi:10.1371/journal.pone.0206097

Shaphan Yong Chia, Subramanian Sevgan + Show 10 more

Open Access

https://doi.org/10.1371/journal.pone.0206097

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Abstract

Efforts to recycle organic wastes using black soldier fly (BSF) Hermetia illucens into high-nutrient biomass that constitutes a sustainable fat (biodiesel) and high-quality protein ingredient in animal feeds have recently gained momentum worldwide. However, there is little information on the most suitable rearing conditions for growth, development and survivorship of these flies, which is a prerequisite for mass production technologies. We evaluated the physiological requirements for growth and reproduction of H. illucens on two diets [spent grains supplemented with brewers’ yeast (D1) and un-supplemented (D2)]. Development rates at nine constant temperatures (10–42°C) were fitted to temperature-dependent linear and non-linear day-degree models. Thereafter, life history table parameters were determined within a range of favourable temperatures. The thermal maximum (TM) estimates for larval, pre-pupal and pupal development using non-linear model ranged between 37.2 ± 0.3 and 44.0 ± 2.3°C. The non-linear and linear day-degree model estimations of lower developmental temperature threshold for larvae were 11.7 ± 0.9 and 12.3 ± 1.4°C for D1, and 10.4 ± 1.7 and 11.7 ± 3.0°C for D2, respectively. The estimated thermal constant of immature life stages development of BSF was higher for the larval stage (250±25 DD for D1 and 333±51 for D2) than the other stages evaluated. Final larval wet weight was higher on D1 compared to D2. The population growth rate was most favourable at 30-degree celsius (°C) with higher intrinsic rate of natural increase (rm = 0.127 for D1 and 0.122 for D2) and shorter doubling time (5.5 days for D1 and 5.7 days for D2) compared to the other temperatures. These results are valuable for the optimization of commercial mass rearing procedures of BSF under various environmental conditions and prediction of population dynamics patterns using computer simulation models.

Highlights

The black soldier fly (BSF) Hermetia illucens L. (Diptera: Stratiomiydae) (Fig 1) is an indigenous saprophagous fly of the Neotropics region
The longest larval developmental time was recorded at 15 ̊C (65 days), while the shortest developmental time was at 30 ̊C (13 days) and 35 ̊C (16 days) when reared on diet 1 (D1) and D2, respectively (Fig 3)
The rate of black soldier fly growth and development was considerably influenced by temperature and diet, which are the two most critical environmental factors

Summary

Introduction

The black soldier fly (BSF) Hermetia illucens L. (Diptera: Stratiomiydae) (Fig 1) is an indigenous saprophagous fly of the Neotropics region. The paucity of scientific data and the reluctance of commercial producers to share detailed information impairs up-scaling BSF production technology among smallholder farmers [13]. As such knowledge on many important aspects related to mass production technologies of BSF remain poorly studied, especially temperature. Among these factors, temperature remains one of the most important factors [14,15] that considerably impacts behaviour, distribution, development rate, immature survival and reproduction, hampering the establishment of successfully rearing systems across the world [16]

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