Researcher(s)
- Todd Harrison, Animal Science, Pennsylvania State University
Faculty Mentor(s)
- Michael Crossley, Agricultural Entomology, University of Delaware
Abstract
The United States is estimated to produce about 66 million tons of food waste per year, contributing to greenhouse gas emissions and missed economic opportunities. However, effects of this waste can be mitigated using a process called “waste upcycling”, where the food waste is turned into biomass that can be used as animal feed and fertilizer. The larvae of an insect, black soldier fly (Hermetia illucens), have proven to be quite efficient at performing this conversion, but questions remain about how this process might attract unwanted organisms that could pose a nuisance to people or a challenge to black soldier fly larvae (BSFL) growth. We examined this at our waste upcycling site on the University of Delaware farm, where we have been upcycling food waste from a local restaurant and brewery in a series of large bins each filled with thousands of BSFL fed different ratios of grain, produce, and meat. We made daily observations of the presence of other insects besides BSFL, as well as measurements of BSFL average mass and bin pH, temperature, and humidity. The predominant non-BSFL insects present in our upcycling bins were blowflies (Diptera: Calliphoridae), often found as dense aggregations of maggots in sections of each bin. However, blowfly presence did not obviously affect BSFL growth, which instead appeared to be more sensitive to the type of food waste provided. Although substrate conditions varied widely throughout the summer, they did not clearly affect BSFL growth. Our findings suggest that BSFL’s ability to break down food waste is not strongly affected by blowfly competition (at least at the levels that we observed), but do point to the need for more controlled experiments to examine potential competitive effects on both insects’ growth as well as waste reduction efficiency.