Spring-emerging adults lay eggs inside hawkweed stolon tips. This species of wasp is able to lay eggs without fertilization, so there are no males. Egg-laying and subsequent feeding by the hatched larvae induce the formation of fleshy, green galls. These structures provide shelter and sustenance for developing larvae that undergo three larval stages within their galls. When galls occur singly, they are pea-sized and shaped and contain one larva, but often individual galls become fused together into a larger structure with multiple larvae, each within their own feeding chamber. The mature, third-instar larvae remain within the gall where they overwinter in an inactive state. In the spring,  pupation occurs within the galls, which have become dried and brown by this stage.