Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/1998
Publication Date: N/A
Interpretive Summary: Each year in the United States, 281 million laying hens produce approximately 420,000 tons of poultry manure. Conventional methods for disposal of this waste matter are inefficient and expensive; in addition, improper manure storage and/or disposal procedures on agricultural facilities can be an important point source of environmental pollution. A possible alternative, biologically based, waste management strategy is to use maggots of the common house fly to digest the manure. To evaluate the potential of this strategy, scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida determined the changes in poultry manure that occur when it is fed upon by house fly maggots and identified ways to minimize the resulting production of adult flies. They found that feeding by fly larvae reduced the weight of the manure by 75%, whereas adult fly numbers could be kept low by controlling the density of larvae in the manure. The results of the study showed that house flies can be used effectively to bioprocess poultry waste and suggested that additional effort is needed to develop genetic strains of house fly that are flightless and which have an enlarged capacity to digest poultry manure, compared with wild flies. These genetic fly strains could be the main component of an environmentally benign technology with broad applicability to the management of animal wastes.
Technical Abstract: This study was made to assess the nature and extent of physical changes in poultry manure that result from feeding activity by house fly larvae (Musca domestica L.). The effects of larval density and of different concentrations of fly degraded manure in the developmental medium were related to changes in manure mass, moisture, and dry matter content. In laboratory assays, larval density changed all manure parameters but it's effect was most notable at the 600 larvae/100 g manure level. In factorial experiments, the concentration of degraded manure (5 levels), but not larval density (4 levels), changed each manure parameter, whereas both manure mass and moisture content were affected by the two-factor interaction. Under conditions in the field, manure parameters did not vary in response to larval density, although feeding activity reduced manure mass by 75%, moisture content by 89%, and manure dry matter content by 35%. Standardized bioassay conditions were developed for quantifying the effect of feeding by house fly larvae on changes in manure parameters and for determining the growth and survival responses of the flies.