SOCIAL-STRUCTURE IN THE ANT LASIUS-FLAVUS - MULTI-QUEEN NESTS OR MULTI-NEST MOUNDS

1. The yellow subterranean ant Lasius flavus is generally considered t o have a single queen in mature nests. Yet, many anecdotal observation s have suggested that the conspicuous earth mounds of this ant may, at least occasionally, contain several queens and their offspring. 2. To estimate the number of matrilines per mound, samples for horizontal s tarch gel electrophoresis were collected from a total of thirty-seven mounds in three sites of old chalk-grassland in southern England. 3. A llozymatic variation at an esterase and hexokinase locus showed that p robably more than 50% of the mounds contained more than one queen and that the mean number of queens per mound is at least 1.5-2. 4. Further results strongly suggested that workers from different matrilines may share the same galleries, at least in the top of the mound. 5. The ap parently variable social structure of Lasius flavus colonies is discus sed, both technically and with reference to ecological processes relat ed to the presence of ants in the nest mounds.