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Toxic Properties of the Chemical Defence Systems in the Competitive Ants Formica rufa and F. sanguinea

1977; Wiley; Volume: 28; Issue: 1 Linguagem: Inglês

10.2307/3543333

1600-0706

Jan Löfqvist, Jan Löfqvist,

Insect and Pesticide Research

Formic acid and substances from Dufour's gland constitute the chemical defence system in F. rufa L. and F. sanguinea Latr. The secretion from Dufour's gland consists in F. rufa mainly of hendecane and tridecane and in F. sanguinea mainly of hendecane, decyl acetate, and dodecyl acetate. The hydrocarbons at least are toxic for the ants also in small amounts. More importantly, however, the hydrocarbons and the acetates act as wetting agents for formic acid, which alone is rather harmless. There are only minor differences between the hydrocarbons and the acetates as wetting agents for formic acid. The substances kill the ants by penetrating their tracheal system, thus easily reaching the vital organs. The hydrocarbons and the formic acid of F. rufa are more toxic for both species than the substances from F. sanguinea. F. sanguinea also seems to be more sensitive than F. rufa to the defence substances from both of the species. The reason may be its smaller size. Differences in the composition of the secretion of Dufor's gland in the two species do not seem to explain the superiority of F. sanguinea in nest competition with F. rufa observed in the field. This may be explained by higher aggressiveness in F. sanguinea.