Protection of Barteria (Passifloraceae) By Pachysima Ants (Pseudomyrmecinae) in a Nigerian Rain Forest

Abstract

In a Nigerian rain forest, occupation of Barteria fistulosa saplings by Pachysima aethiops ants results in the plants having more leaves, more branches, more leaves per branch, and less damage to the shoot tips than do unoccupied Barteria. At present this difference is the result of insect damage to unprotected Barteria, but several traits of the ant colony suggest that in the recent past, large browsing mammals may also have been a threat to Barteria. These traits include a few large workers per colony, a deeply painful sting, and the habit of frequently dropping from the Barteria crown. Pachysima workers attack plants adjacent to their Barteria and clean the large Barteria leaves of debris and epiphyllae.