Protection of Passiflora glandulosa (Passifloraceae) against herbivory: Impact of ants exploiting extrafloral nectaries
In French Guiana we studied the protective role of four ant species on Passiflora glandulosa (Passifloraceac), a liana bearing extrafloral nectaries. By ant exclusion experiments, using birdlime, we showed that stems from which ants were excluded were significantly more attacked by phytophagous insects than control stems visited by ants. Among the ant species that protected P. glandulosa, Camponotus blandus and Ca. melanoticus are ground-nesting, arboreal-foraging species that share territories, one species being diurnal, the other nocturnal. These ants visit and protect plants whose shoot tips are located on or near the ground, i.e., plants creeping on the ground and/or young individuals. The two other species of ants observed on P. glandulosa in the site, Ca. femoratus and Crematogaster limata parabiotica, are typical arboreal ants that can! protect large plants climbing on trees. We conclude that it is advantageous for a liana to be able to establish associations with a range of different ant species providing continuous defense of shoot tips as they grow toward the canopy.