The importance of ant gardens in the pioneer vegetal formations of French Guiana (Hymenoptera : Formicidae)

We compared the spatio-temporal distribution of arboreal ant species in pio neer vegetal formations of three different ages in French Guiana in order t o examine the ants' role in the dynamics of this suspended habitat. Among t he types of arboreal ant nests, ant gardens were significantly the most fre quent, whatever the age of the pioneer formation; myrmecophytes sheltering ants in domatia occupied the second position. Other kinds of arboreal ant n ests (silk or carton nests; opportunistic nesting in hollowed rotten branch es or between tree bark and epiphytes; nesting in the ground at the bases o f trees) were recorded at lower levels. Among the ant species able to build ant gardens, the Ponerinae Pachycondyla goeldii was unexpectedly predomina nt in young formations. However, its presence decreased as a function of th e age of the formation, while ant gardens sheltering Camponotus femoratus o r Crematogaster limata parabiotica, either alone or in parabiosis, increase d. The epiphytic composition of the ant gardens depended on the ant species sheltered. In parabiosis, this composition was mostly influenced by C.femo ratus. This information enabled us to confirm our hypothesis that the natur e of the ant species distribution and its accompanying impact on pioneer ve getal formations is not static, but changes over time.