WORKER POLYMORPHISM IN THE RED-HEAD BULLDOG ANT (HYMENOPTERA, FORMICIDAE), WITH DESCRIPTION OF NEST STRUCTURE AND COLONY COMPOSITION

Five nests of Myrmecia froggatti were dug out in the dry Eucalyptus wo odland around Mt. Gournet, Queensland, northern Australia. Nest struct ure was simple; a single, vertical unbranched shaft that connected 6-1 2 chambers down to 80-145 cm. Colonies were monogynous and of small si ze; each contained one ergatoid queen, an average of 38 workers, and s everal brood. Ergatoid queens had a sperm-filled spermatheca and betwe en 15-18 ovarioles, whereas workers had an empty spermatheca and 4-15 ovarioles. Pronotum width and head width of workers showed isometric g rowth. However, allometric growth was observed between the width of th e pronotum and the width of the fourth segment of the abdomen. Number of ovarioles was positively correlated with the abdomen width. Thus, l arge sized workers had a disproportionally larger number of ovarioles than smaller sized workers. The function of large workers of M. frogga tti is discussed.