Acacia Ants (Peudomyrmex sp.) gathered at extrafloral nectaries of Bull's Horn Acacia (Acacia collinsii) stem, Santa Rosa National Park, Costa Rica. An example of mutualism: the ants inhabit the acacia plant's hollow swollen spines and obtain food from the plant, while protecting the plant from browsing by herbivores and keeping it clear of vines.
Slide # IN4-177