Production of trophic eggs by virgin workers in the ponerine ant Gnamptogenys menadensis

Abstract. Most colonies (thirty‐five out of thirty‐seven) of the ant Gnamptogenys menadensis (Mayr) (Hymenoptera: Formicidae: Ponerinae) lack queens. Mated workers produce reproductive eggs, whereas virgin workers can lay only smaller trophic eggs (350 ovipositions observed). These two egg types are morphologically distinct (e.g. in the pattern of oogenesis and ultrastructure of membranes and micropyle) and relate to different ovarian characteristics (ovariole length, number of yolky oocytes and yellow bodies). When reproductives are removed, a small number of virgin workers switch to producing reproductive eggs, although only 3% of these develop into larvae. Once workers are mated, up to 50% of their eggs develop further. Trophic eggs are generally absent in social insects lacking physical castes, and we review adaptive explanations of its occurrence in G. menadensis .