MORPHOLOGY AND REPRODUCTIVE-BEHAVIOR OF INTERCASTES IN THE PONERINE ANT PACHYCONDYLA-OBSCURICORNIS

Queens are usually the functional reproductives in Pachycondyla obscur icornis, but none were found in one colony collected near Brasilia. In this colony, three adults differed morphologically from workers; alth ough wingless, their thorax was more or less like that of winged queen s (scutum and scutellum distinct; metanotum larger than that of worker s). Another 11 such individuals were found by opening cocoons. We cons ider that these are intercastes (sensu Peeters, 1991). Two adult inter castes were mated and laid eggs. In contrast, all the workers were vir gin, but some laid distinct trophic eggs which were fed to the two rep roductives. Following experimental removal of the intercastes, dominan ce interactions began among the workers, and reproductive eggs were th en laid. Intercastes with a reproductive function have not been report ed previously in the Ponerinae. They are distinct from ergatoid queens (permanently wingless reproductive caste) or gamergates (mated egglay ing workers).