Wednesday, February 27, 2008

Yellow Meadow Ants (Lasius flavus) & friends

Today I prised up Purbeck Slab, a piece of local limestone brought home many years ago from Brightling a few miles west. It was gradually being covered by vegetation moving in from the sides, so I thought if I lifted it up and put it down again it could spend another four and a half years settling.

Underneath there was a colony of yellow meadow ants - not a mound building tribe in this case. The pictures show, from bottom to top, an ant with what looks like a pupa, a Cyphoderus springtail (probably Cyphoderus albinus) a tiny, fast running species almost always found in ants' nests and another very pale springtail that looks pretty subterranean.

These creatures give me an excuse to quote a passage about meadow ants from Charles Elton's splendid book The Pattern of Animal Communities (Chapman and Hall Ltd, London, 1966): “The yellow ant survives ... quite well in subterranean nests that do not have mounds accumulated above them .... The population of workers in a nest may be anything between 2000 and nearly 25,000 .... This dense army .... is engaged both in nest duties (which include transport of soil on to the mounds, tending young and such things as licking the eggs of aphids to keep them healthy for the later planting on roots), and in travelling along tunnels within a territory beneath the turf to collect food for the nest. Various small preys are captured including some of the aphid species that are farmed on the roots of plants. On one small patch about 20 yards across, in a mixture of open and meadow within the shelter of trees, a dense mixture of Lasius flavus and L. niger nest populations were found by Pontin to be farming 16 species of aphids and one coccid on the roots of various limestone grasses and herbs. At Silwood Park the mound-making populations were farming about 7 kinds of aphids on roots of 4 species of grass and 1 composite.”

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