Black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), and house fly, Musca domestica L. (Diptera: Muscidae), larvae reduce livestock manure and possibly associated nutrients: An assessment at two scales

Authors: MIRANDA, CHELSEA - Evo Conversion Systems, Llc; Crippen, Tawni - Tc; CAMMACK, JONATHAN - Evo Conversion Systems, Llc; TOMBERLIN, JEFFERY - Texas A&M University

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2021
Publication Date: 3/26/2021
Citation: Miranda, C.D., Crippen, T.L., Cammack, J.A., Tomberlin, J.K. 2021. Black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), and house fly, Musca domestica L. (Diptera: Muscidae), larvae reduce livestock manure and possibly associated nutrients: An assessment at two scales. Environmental Pollution. 282. Article 116976. https://doi.org/10.1016/j.envpol.2021.116976.
DOI: https://doi.org/10.1016/j.envpol.2021.116976

Interpretive Summary: The large industrial scale production of insects for uses as a protein source and for waste management is becoming vital to our society. Large volumes of manure are produced during animal production around the globe that must be managed, utilized, or disposed of properly. Flies offer a partial solution with their abilities to reduce these wastes and heavy metal pollutants. Meat and crop proteins are being supplemented by insect proteins for many feeds across the globe, yet science-based studies behind the mass rearing of insects are still in their infancy. In the current study, the percent change in the composition of nutrients, heavy metals, and fiber, in dairy, poultry, and swine manure degraded by either black soldier fly (BSF) or house fly (HF) larvae was explored. Pre-digested and post-digested manure was collected from studies that differed in production scale. Results show that nitrogen is a key nutrient changed by larval digestion of manure by both species, regardless of the production scale. Scale did significantly influence reductions of other nutrients, as did the type of manure in which the insects were reared. Ultimately, this study demonstrated that manure type and rearing scale impacts the ability of these fly larvae to reduce nutrients and heavy metals in manure, and thus insect production management procedures need to match the production emphases of the insects for waste management or protein products.

Technical Abstract: The industrial scale production of insects for uses as a protein source and for waste management is becoming vital to our society. Large volumes of manure are produced by confined animal facilities around the globe that must be managed, utilized, or disposed of properly. Flies offer a partial solution with their abilities to reduce these wastes and heavy metal pollutants. Meat and crop proteins are being supplemented by insect proteins for many feeds across the globe, yet science-based studies behind the mass rearing of insects are still in their infancy. In the current study, the percent change in the composition of nutrients, heavy metals, and fiber, in dairy, poultry, and swine manure degraded by either black soldier fly (BSF) or house fly (HF) larvae was explored. Pre-digested and post-digested manure was collected from four independent studies that differed in production scale (number of larvae and feeding regimen): 1) BSF small scale (100 larvae fed incrementally), 2) HF small scale (100 larvae fed incrementally), 3) BSF large scale (10,000 larvae fed a single time), and 4) HF large scale (4,000 larvae fed a single time). Results indicate that nitrogen is a key nutrient impacted by larval digestion of manure by both species, regardless of scale. However, scale significantly impacted reductions of other nutrients, as did the type of manure in which the insects were reared. Ultimately, this study demonstrated that manure type and rearing scale impacts the ability of BSF and HF larvae to reduce nutrients and heavy metals in manure, and thus insect management procedures need to be congruent with production emphases of the insects for waste management or protein products.