The nest chemistry of two seed-dispersing ant species.

Nests of Myrmica discontinua and Formica canadensis from meadows in the vicinity of the Rocky Mountain Biological Laboratory, Colorado, USA were analysed for fifteen plant macronutrients, micronutrients and heavy metals. Nest samples were compared with control samples taken from surrounding soils. Principal components analysis and discriminant function analysis show that the nest chemistry of F. canadensis differs significantly from that of M. discontinua. Also, nest chemistry differs from that of the surrounding soils. Both kinds of nests contain elevated levels of phosphorus relative to adjacent soils, but F. canadensis nests may be deficient in the micronutrients zinc, iron and manganese. On the other hand, the nests of M. discontinua are also richer in ammonium and percent organic matter. These results are discussed with respect to the hypothesis that relocation of ant-dispersed seeds into ant nests may be advantageous to the plant species involved. It is suggested the relocation to Myrmica nests, rich in phosphorus, potassium and nitrogen, may result in greater survivorship of seedlings.