Temporal and spatial variation in extrafloral nectar and associated ants in Canavalia rosea (Fabaceae) on coastal dunes along the Gulf of Mexico

Abstract

ABSTRACT Extrafloral nectar production can vary depending on the structure of the plant in which it is found, as well as environmental conditions. This can in turn influence plant-ant interactions. We evaluated the role of extrafloral nectaries of Canavalia rosea as ant attractants in a coastal zone of the Gulf of Mexico. We compared the productivity of the extrafloral nectaries present on leaves and inflorescences, as well as between day and night, and described the associated ant community. Nectar volume and concentration were higher in inflorescences than in leaves, and the rate of ant visitation was higher in inflorescences during the day. These results suggest congruence with the Optimal Defense Hypothesis. Nectar volume was generally greater during the night in both structures, but sugar concentration did not differ between day and night. We found a turnover in the ant species visiting C. rosea, with S. geminata being the most abundant species. The extrafloral nectar of C. rosea attracts several ant species and probably other arthropods, providing a valuable resource in a stressful system.