A NOTE ON MUCILAGE AND HERBIVORE DAMAGE ON BRASENIA SCHREBERI IN A NORTHERN MICHIGAN LAKE

摘要

Herbivory is an important part of aquatic macrophyte communities, in which the intensity of her-bivory can impact the composition of macrophyte communities. The undersides of the leaves of Schreber's watershield, Brasenia schreberi, are covered with athick, clear mucilaginous substance thought to reduce herbivory. Our study tested predictions of an earlier herbivore study by examining B. schreberi in situ and analyzing how herbivore damage correlates with the amount of mucilage found on the leaves.In September 2014, we sampled floating leaves in a small lake in Marquette County, Michigan. For each leaf sampled, we weighed the mucilage, measured the leaf, and estimated the amount of herbivore damage using Image J software. We found that the amountof herbivore damage on leaves differed significantly among the different herbivore larvae and with respect to leaves with no damage, which had the most mucilage. These results suggest that herbivores may be deterred from leaves with more mucilage and that different herbivores have different levels of tolerance to mucilage. Future studies should be conducted in which plants are grown in the laboratory, the mucilage is manipulated, and herbivore behavior in response to the amount of mucilage can be measured.