Physiological trade-offs of forming maggot masses by necrophagous flies on vertebrate carrion

Abstract

Necrophagous flies that colonize human and animal corpses are extremely efficient at locating and utilizing carrion. Adult flies deposit eggs or larvae on the ephemeral food resource, which signals the beginning of intense inter- and intra-species competition. Within a short period of time after egg hatch, large larval aggregations or maggot masses form. A period of intense larval feeding ensues that will culminate with consumption/decomposition of all soft tissues associated with the corpse. Perhaps the most distinctive feature of these feeding aggregations is heat production; that is, the capacity to generate internal heat that can exceed ambient temperatures by 30°C or more. While observations of maggot mass formation and heat generation have been described in the research literature for more than 50 years, our understanding of maggot masses, particularly the physiological ecology of the aggregations as a whole, is rudimentary. In this review, an examination of what is known about the formation of maggot masses is presented, as well as arguments for the physiological benefits and limitations of developing in feeding aggregations that, at times, can represent regions of intense competition, overcrowded conditions, or a microclimate with elevated temperatures approaching or exceeding proteotoxic stress levels.