Colony structure and reproduction in the thelytokous parthenogenetic ant Platythyrea punctata (F. Smith) (Hymenoptera, Formicidae)

An important evolutionary characteristic of the formicine subfamily Ponerin ae is the occurrence of various alternative reproductive tactics within sin gle species. In Platythyrea punctata Smith, 1858, queens, gamergates and pa rthenogenetic workers co-occur in the same species. Morphological queens, b oth alate and dealate, were present in only 29 percent of the colonies coll ected in Florida, but absent from colonies collected in Barbados and Puerto Rico. One of the six queens which were dissected (three alate and three de alate) was found to be inseminated but not fertile. Instead, in most queenl ess colonies, a single uninseminated worker monopolized reproduction by mea ns of thelytokous parthenogenesis, i.e., it produced female offspring from unfertilized eggs. A single mated, reproductive worker (gamergate) was foun d dominating reproduction in the presence of an inseminated alate queen in one of the Florida colonies. Thelytokous parthenogenesis was examined in ar tificial groups of virgin laboratory-reared workers, where one worker typic ally monopolized reproduction despite the presence of several individuals w ith elongated ovaries. In 16 colonies collected in Florida, a total of 66 i ndividuals differed morphologically from queens and workers. Their thorax m orphology varied from a worker-like to an almost queenlike structure. We re fer to these individuals as "intercastes" (sensu Peeters, 1991a). The remar kable complexity of reproductive strategies renders P. punctata unique with in ants.