QUEEN ACCEPTANCE AND NESTMATE RECOGNITION IN MONOGYNE AND POLYGYNE COLONIES OF THE ANT FORMICA-TRUNCORUM

In ants permanent polygyny (the permanent presence of multiple reprodu cing queens) commonly arises secondarily through the adoption of daugh ter queens. Polygyny decreases the relatedness among nestmate workers and consequently the genetic benefits from helping close relatives. He nce, studies on nestmate recognition and queen adoption may shed light on how queen numbers are regulated as well as on causes of variation in queen number. In this study acceptance of nestmate and non-nestmate young queens in;monogyne (single queen) and polygyne colonies of the ant Formica truncorum was compared. Queen number varies in this specie s: in some populations colonies have a single queen (monogyne populati ons), whereas in others all colonies contain several functional queens (polygyne populations). Young queens introduced into the experimental colonies varied with respect to female origin (nestmate versus non-ne stmate), dispersal prospects as reflected by wing status (wingless ver sus winged) and mating status (mated versus virgin): Monogyne and poly gyne colonies differed in one fundamental way in their responses to in troduced females. Workers of monogyne colonies, but not those of polyg yne colonies, discriminated between nestmate and non-nestmate females. In both monogyne and polygyne colonies mated females were destroyed t o a higher extent than virgin ones, largely independently of wing stat us. None the less, mated females may have a reasonable chance of becom ing adopted in their natal colony both in monogyne and polygyne coloni es. If so, the single-queen status of monogyne colonies may be retaine d by a high rate of female dispersal in combination with few intra-nid al mating opportunities. Polygyne colonies are characterized by both a low degree of female rejection and low levels of discrimination betwe en nestmates and non-nestmates. Nevertheless, previous genetic and beh avioural data on female dispersal suggest that the majority of new que ens adopted into polygyne colonies are their own daughters. (C) 1997 T he Association for the Study of Animal Behaviour.