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

1. The yellow subterranean ant Lasius flavus is generally considered to have a single queen in mature nests. Yet, many anecdotal observations 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 starch gel electrophoresis were collected from a total of thirty-seven mounds in three sites of old chalk-grassland in southern England. 3. Allozymatic variation at an esterase and hexokinase locus showed that probably 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 apparently variable social structure of Lasius flavus colonies is discussed, both technically and with reference to ecological processes related to the presence of ants in the nest mounds.