Nutrient and moisture transfer to insect consumers and soil during vertebrate decomposition

Decomposition of organic matter leads to the redistribution of nutrients to organisms and the environment. Yet knowledge of this process has focused largely on plant-derived organic matter, with little known about relative quantities of nutrients and moisture transferred from decomposing animal remains to insect consumers and soil. We used a replicated and spatially blocked experiment to quantify the moisture, carbon, nitrogen, and phosphorous content of rabbit carcasses, maggot consumers, and soil over 20 days of decomposition. We found that maggot biomass reached 22% of the fresh rabbit carcass, or 39% of the consumable soft tissues. Maggots were comprised of 68% moisture, and their dry mass was comprised of 25% carbon, 4.9% nitrogen, and 0.8% phosphorous. Soils accumulated approximately 12.9% of the total carcass moisture, but only 0.7% of the carcass dry mass. The largest quantity of carcass mass loss was attributable to evaporation of moisture to the atmosphere (45%). Approximately 9% of the initial carcass mass was left as unconsumed remains. Our study provides estimates of the quantities of nutrients moving from vertebrate carcasses to insect consumers and soil. This knowledge is critical to scaling up the effects of carcasses and to developing our understanding of their role in biogeochemical cycling in ecosystems.