Field of Science

Leafy passion for phony eggs

One of the best things about rain forest when you're teaching or studying rainforest is the myriad of interactions among organisms. You just see them everywhere. The leaf above is from a vine found growing on top of a clump of Heliconia near our cabina. It's a passion vine, Passiflora biflora. Notice the 8 conspicuous fake eggs on the leaf. Butterflies that specialize on Passiflora vines for their larvae to feed on see these fake eggs and decide not to add another egg to a leaf where other larvae will be feeding first.  But these fake eggs are also nectaries on the back side, glands that secrete nectar and attract ants that will defend their nectar source thus providing another protection from herbivory. Indeed the back side of this leaf had several ants on board.  Note that the top of the 2-lobed leaf is oriented upside down in this image with the apex, a tiny tip pointing down

No comments: