Queen polymorphism and queen-morph related facultative polygyny in the ant, Myrmecina graminicola (Hymenoptera, Formicidae)

Abstract

Polymorphism of the functional queens in Myrmecina graminicola is analyzed. Both gynomorphs (G-♀♀; G) and a wide range of intermorphs (I-♀♀; I) occur, which all are usually mated and egg-laying. Colonies having a gynomorphic queen are always monogynous, whereas about 57% of all colonies with intermorphic queens are polygynous, having two or more coexisting functional queens. The female sexual offspring of individual gynomorphic queens either consists of gynomorphs only, or exclusively of intermorphs. Intermorphic queens may have exclusively intermorphic female sexual progeny, or simultaneously both gynomorphs and intermorphs. Single colonies in laboratory culture produce the same kind of female progeny over several subsequent breeding cycles (artificially compressed "years" of 9–10 months). No environmental influence on queen morph determination could be detected. A genetically mediated queen polymorphism, as in Harpagoxenus sublaevis and Leptothorax sp. A, is suggested. Colony sizes vary considerably, with polygynous I-queen colonies being largest (57.2 ± 34.3 s.d. workers), followed by G-queen colonies (44.6 ± 22.7 s.d.) and monogynous I-queen colonies (34.4 ± 23.7 s.d.), suggesting occasional budding of polygynous colonies.