Inter-Island Environment Meeting 2020 20th Anniversary marked by first...
Exciting Ant News...
... we have a newly discovered Formica pratensis nest.
In Guernsey, black-backed meadow ants, Formica pratensis, are typically found on the south cliffs. This rare ant species is Near Threatened on the IUCN Red List, so we survey the nests every year and mark their nests with red flags so the land management team can see them.
This September, while wandering the lanes of St Saviours, a long way from the south cliffs, Russell Le Conte took this photo.
Could it be?
A black-backed meadow ant, Formica pratensis, nest so far from what we consider their normal habitat?
A flurry of emails back and forth and Julie, our Ant Survey Coordinator, headed off in search of the nest. Other local entomologists made plans to visit it. Julie swiftly reported back she was reasonably certain, especially as there was a mound – which is a key identifier. The nest was about 60 x 60 cm, very active and in good condition. It appears to be quite on its own as she checked the nearby banks.
Barry Wells investigated too, returning with some incredible macro-photographs. Click on the photos to see close up image.
Everything suggested that this nest might be a remnant of a population that used to be far more widespread in years gone by. Ant expert Phil Attewell was approached and, this week, we got confirmation.
Phil Attewell identification:
Yes, definitely Formica pratensis. A nice find, and confirmation that these isolated inland nests are still surviving, and apparently thriving, in the lanes where they seem to have cropped up here and there over the years in Guernsey, and were on the maps that Charles David used to produce. Good to see a brand new one!
Isolated single nests are the usual norm for F. pratensis. The apparently mutually friendly ‘supercolonial’, probably polygynous, nests of the Guernsey cliffs are not its traditional habit elsewhere, although similar populations are recorded in some sites, e.g. one or two places in the Netherlands, as Cedric Collingwoood used to tell me about.
Single, isolated nests like this one will have been started by a mated female having flown from its mother nest, and ‘taken over’ a nest of either F. fusca or F. cunicularia, by entering it and usurping the existing queen. On the cliffs, I think new nests are mostly started by mated queens going off with a few workers from their mother nest (“splitting” or “fission”), or simply attracting passing workers to them – “worker capture”, as it’s sometimes known. Wood ant queens cannot start colonies unaided. The two modes of colony reproduction are therefore in evidence on Guernsey.
The isolated nests will therefore usually only live as long as the founding queen (monogyny). There must be many dotted about undiscovered in open hedges and on lane banks.
The weather this year on the whole must have been good for the F. pratensis, although the recent very wet and relatively cool spell will have been unwelcome.