THE EXTRAFLORAL NECTARIES OF IPOMOEA LEPTOPHYLLA (CONVOLVULACEAE)

Abstract

Ipomoea leptophylla Torr. (Convolvulaceae) is a sprawling dry‐site morning glory with two types of extrafloral nectaries: foliar nectaries and nectaries on the outside of the sepals. Both are shown to greatly increase insect visitation to the plant. Ants visiting sepal‐surface nectaries significantly decrease flower damage caused by grasshoppers and seed losses caused by bruchids. These results are similar to those for I. carnea and other plants whose extrafloral nectary‐ant interactions have been studied, but differ in detail. This is the first demonstration of antiherbivore defense of a prairie plant by nectary visitors.