Investigating Insect Interactions on the Tropical Tree, Pentaclethra macroloba
Mentor:Elizabeth Braker , Associate Professor of Biology , Occidental College
Pentaclethra macroloba is a dominant canopy tree found in humid tropical forests from Honduras to Brazil, comprising 30-40% of all basal area at La Selva Biological Station, Costa Rica. To understand the full role that Pentaclethra macroloba plays in its surrounding environment I took a closer look into the interactions of the insects most abundant on P. macroloba; which include caterpillars, ants, and treehoppers. For 2 months in La Selva Biological Station, I observed and collected insects from P. macroloba saplings. I conducted a census for ants on 38 saplings four times a day: early morning, late morning, dusk, and one in the evening; so that we could measure most prevalent ant species as well as the time they are most active. The results clearly indicate that Crematogaster was the most abundant ant species and were most active at dusk (4:00pm). In the treehopper experiment I visited 5 stems that once had both treehoppers and ants and recorded the number of ants, number of treehoppers and their behavior. The ants were often next to or on top of the treehoppers. The numbers of the treehoppers dwindled as the time passed, indicating that the treehoppers spent a period of time without moving from a particular stem and then dispersed. Finally to study the herbivores of this canopy tree I collected a total of 31 caterpillars, 29 different species, found eating P. macroloba and reared them to adulthood. The information about the caterpillars collected, as well as six pinned Lepidoptera adults, and one parasitoid will be added to a database of known herbivores of P. macroloba. The compiled information will give insight into the variety of insects supported by this dominant canopy tree.