Natural and experimentally made holes in the walls of Cecropia stems, exposing the interior of the internode, and repair patches applied by ants (scale bars, mm) a a natural entrance to an internode opened and maintained by the ants b a newly drilled 6.4 mm hole in a stem (diameter of seventh internode from terminal bud = 19 mm, of 23 internodes total) c rapid reduction in hole diameter after 2.5 hours (arrow points to the remaining hole) d slower reduction in hole diameter after 24 hrs (dashed arrow points to the remaining hole), with a light-colored patch over half the hole (solid arrow) (diameter of sixth internode from terminal bud = 1 cm, of 50 internodes total).