We have analysed the distribution of queens under stones at the core and at the periphery of a supercolony of Lasius neglectus that occupies 14 ha at Seva (NE Spain). Queens were not found alone, but rather within worker groups. Density at the center (mean ± s.d.: 1.38 ± 2.87 queens/stone; n = 100 stones; range 0 -14) was not different from density at the periphery (1.18 ± 2.38; range 0 -12). The estimate of the number of queens found under stones for the whole colony is about 35500. Egg-laying rates for queens from these two zones were obtained in the laboratory, at three different temperatures, and there were no differences detected. The presence of brood stages, from eggs to cocoons, was also similar in both zones. The homogeneous distribution of colony components may indicate that the area occupied by L. neglectus has already reached saturation. With a different technique -soil core extraction -we could estimate the density of workers in the soil: 800 workers per m 2 . Soil cores had 6.28 ± 20.0 workers/core (range: 0 -173), giving a rough estimate of 1.12 ¥ 10 8 workers in the soil, for the entire colony. Though few, some queens were also recovered from soil cores. Queen numbers for the supercolony, based on queens found in the soil, reaches the astounding level of 360000. Numbers are consistent with previous predictions.

We surveyed ants in 16 forest remnants in the Vallès lowlands north of Barcelona, Spain: eight with invasive exotic ants (IE = Linepithema humile and/or Lasius neglectus) present, seven with native parasitic ants (P = Lasius meridionalis, Lasius carniolicus, Plagiolepis xene, Chalepoxenus muellerianus, and/or Polyergus rufescens) present, and one remnant with both invasive exotic and parasitic ants present. Forest remnants with IE ants were smaller, more isolated, had greater perimeter/area, lower ant species density, and lower ant species richness than remnants with P ants. The community composition was also significantly different, with greater dissimilarity within remnants with alien, invasive species. The presence of some species is bio‐indicator of low disturbance, whereas others are indicative of high disturbance. Our findings underscore the value of different types of ants as bio‐indicators of fragmentation and habitat quality.

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