CAMPONOTUS (COLOBOPSIS) (MAYR 1861) AND MACARANGA (THOUARS 1806) - A SPECIFIC 2-PARTNER ANT-PLANT SYSTEM FROM MALAYSIA

Within the paleotropical tree genus Macaranga (Thouars 1806) (Euphorbi aceae), the majority of ant-plant species are associated with speciali zed Crematogaster (Lund 1831) partner ants from the subgenus Decacrema (Myrmicinae). We have now discovered a completely different myrmecoph ytic system in which an ant species of the Formicinae lives in symbios is with the peat swamp forest tree Macaranga puncticulata (Gage 1922). M. puncticulata twigs develop spacious cavities (domatia). An undescr ibed Camponotus (Colobopsis) (Mayr 1861) species of the C. saundersi-g roup was the dominant ant inhabitant (65% of the investigated plants) at forest sites, but this species, provisionally named C. (Colobopsis) sp. 1, was only rarely found at open stands. Another 29 opportunistic stem-nesting ant species were collected less frequently. None of them were Crematogaster (Decacrema) ants. C. (Colobopsis) sp. 1 has never been found to nest away from M. puncticulata. The mated queens are cap able of locating young M, puncticulata plants and of chewing entrance holes into the domatia. In contrast to all the other obligate plant-an ts associated with Macaranga, C. (Colobopsis) sp. 1 never cultivates a ny trophobionts, neither inside nor outside the domatia. Instead of ta king up honeydew from coccids, the ants obtain carbohydrates from extr afloral nectaries along the leaf margins of M. puncticulata. This food source is an uncommon trait within Macaranga myrmecophytes. The assoc iation of C. (Colobopsis) sp. 1 with M, puncticulata is therefore the first record of a two-partner ant-plant system without endophytic cocc ids in the genus Macaranga.