Major and minor workers of the turtle ant Cephalotes pusillus engage in trophallaxis food-sharing behavior. Carrancas, Minas Gerais, Brazil

Cephalotes pusillus - turtle ant, major worker. The deep recesses on the head (the "scrobes") allow the ant to fully retract her delicate antennae. Carrancas, Minas Gerais, Brazil

Cephalotes varians, turtle ant soldier. The bizarre disc on the head is used as a living door to block the nest entrance. Florida Keys, USA