Observations of insects and their feeding marks on leaves in modern forests confirm indications from fossil leaf deposits that the diversity of chewing damage relates directly to diversity of the insect population that created it, according to an international team of researchers.
"The direct link between richness of leaf-chewing insects and their feeding damage across host plants in two tropical forests validates the underlying assumptions of many paleobiological studies that rely on damage-type richness as a means to infer changes in relative herbivore richness through time," the researchers report in today's (May 2) issue of a.
Studies of leaf chewing include observation of the leaves, but rarely include all the insects that actually made the marks. Mnica R. Carvalho, graduate student, Cornell University and Peter Wilf, professor of geosciences, Penn State, and colleagues looked at leaf predation in two tropical forests in Panama to test for a relationship between the richness of leaf-chewing insects and the leaf damage that the same insects induce.
Using Smithsonian Tropical Research Institute canopy-access cranes and working in the dark at almost 200 feet high in the treetops at new moon during two summers the researchers collected a total of 276 adult and immature leaf-chewing insects of 156 species. While the largest category of insect was beetles, leaf chewers among grasshoppers, stick insects and caterpillars, as well as a few ants, were also collected.
The team also collected fresh leaves of the insects' host plants and placed the insects in feeding experiment bags with these leaves. They allowed adult insects to feed for two to three days and immature stages to feed until full maturity when possible. The researchers then classified the damage to the leaves into categories, in the same way they catalog fossil leaf- chewing damage.
|Contact: A'ndrea Elyse Messer|