Megan M. Burns
Department of Biology, Carleton College, Northfield, MN, USA, 55057
Abstract. It is hypothesized that the observed delayed greening of leaves in many tropical plants are used as an antiherbivore defense, an antifungal defense or possibly both. The young leaves of these plants are red, blue, pink, white or light green; they turn dark green only after reaching maturity. They lack the chlorophyll, chloroplasts, rubisco, and photosynthetic enzymes which allow photosynthesis to occur, but which are also the nutrients upon which herbivores feed. Myriocarpa longipes is one of these tropical delayed greening plants; the young leaves are red in color. This experiment focused on the antiherbivore defenses of the delayed greening leaves. The study was carried out at La Selva Biological Station in Costa Rica, using six M. longipes plants, 30 red leaves and 30 green leaves (five of each from each individual). The percent of leaf area eaten over a seven-day period was calculated using initial and final leaf area measurements. The percent of area of an individual leaf eaten over the seven days is greater for the green leaves than for the red leaves, indicating the delayed greening is used as an antiherbivore defense for M. longipes.