Population structure of the male-polymorphic ant Cardiocondyla obscurior

Males of the myrmicine ant Cardiocondyla obscurior Wheeler are either wingless, ergatoid fighters or winged, peaceful dispersers. Collection of 124 colonies from Bahia, Brazil, between January 2003 and January 2004 revealed that ergatoid males and a few female sexuals were produced throughout the year. Female sexual production peaked in April 2003 and was followed by a significant decline in colony size, presumably due to colony fragmentation or budding. Not a single winged male was found, suggesting that in this population they are indeed reared only under particularly stressful conditions, as previously observed in the laboratory.