Interaction between ants and orchids in the Soconusco region, Chiapas, Mexico.

DAMON A, PÉREZ-SORIANO MA. 2005. Intereaction between ants and orchids in the Sonocusco region, Chiapas, Mexico. Entomotropica 20(1): 63-69. Ants were seen to visit extrafloral nectar sources mostly on the flower bases and petiole junctions of Encyclia cordigera , E. chacaoensis and E. belizensis var. parviflora and the production of extrafloral nectar in relation to the presence of ants was observed during the flowering periods of these orchids in the Regional Botanical Garden "El Soconusco" and the orchidarium Santo Domingo, in Chiapas, Mexico. Ants were also seen to feed on secretions produced at flower bases and on the surface tissue and tips of buds of Catasetum integerrimum and Cycnoches ventricosum . Mention is included of ants associated with other species of orchids collected in the field. Eleven species of ants were fully identified out of a total of 19 species collected. Most species were common inhabitants of secondary vegetation, with some species registered as pests in agroecosystems and human dwellings. It was not clear how the plants benefited by investing scarce resources in the provision of food to attract ants, but a defense role is possible for one species, Camponotus novogranadensis , which was observed to be aggressive when the plant was disturbed by touching during visits to the extrafloral nectaries of E. chacaoensis. It is suggested that E. belizensis var. parviflora benefits from the presence of Crematogaster aff. torosa resident in old pseudobulbs, which effectively act as domatias, by absorbing nutrients from organic wastes produced by those ants