Effects of Larval Secretions on Queen Fecundity in the Fire Ant

Abstract

For social insects, queen fecundity is central to queen survival. In addition, coordinating workload, in the form of hungry larvae, with labor, in the form of workers, is critical to queen survival. Such coordination is accomplished by transporting waste products from molting fourth instars to queens that then amplify queen egg production. The source of the fecundity-amplifying factors that are transmitted from larvae to queens is still under debate. This article reports a case study on the red imported fire ant, Solenopsis invicta Buren, demonstrating that larval excretory products amplified queen fecundity rather than larval fecal fluids, larval saliva, or nutrients. Queens were active participants in their intake of fecundity-amplifying factors, often grazing over larvae, squeezing and ingesting the expelled droplet. In summary, these findings support a queen-centered rather than a worker-centered model for the social regulation of queen fecundity and survival.