Protein-lipid consumption in fire ants

Ants are opportunist feeders and can often be found foraging on vertebrate carrion. Previous research has shown that fire ants are attracted to vertebrate carrion in the field and in laboratory settings. However, recent data associates the consumption of vertebrate carrion with lower colony survival, growth, and reproduction. When fed vertebrate carrion, fire ants had poor colony performance, whereas fire ants that fed on insect carrion were overall healthier. We hypothesize that fire ants are attracted to vertebrate carrion not because it is a high-quality food, but rather because it hosts a large range of other invertebrates that can serve as prey for fire ants. The current study was conducted to compare the nutritional value of rodent carrion and of maggots fed on rodent carrion, determine which of these is associated with better colony performance, and what nutritional content can be linked with better colony performance, with a focus on the relative amounts of protein and lipid. We hypothesized that the nutritional content of insect feed is closer to ants’ nutritional requirements than nutritional content of rodent carrion. We discuss our results in the context of a unique tri-trophic interaction, where fire ants are attracted to vertebrate carrion, not to feed on the carrion itself, but to predate other carrion-feeding insects.