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.
A scarab beetle (Coleoptera: Scarabaeidae) observed inducing margin feeding on leaves from Tapirira guianensis Aubl. tree during feeding experiments.
Credit: Wilf, Penn State
Studies of leaf chewing include observation of the leaves, but rarely include all the insects that actually made the marks. Mónica 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.
"This is the first attempt to compare leaf-chewing damage inflicted by many kinds of living insects on many kinds of plants throughout a large forest area, both to the culprit insects and to the leaf damage we see in the fossil record," said Carvalho. "We mounted 276 of the insects with their damaged leaves and deposited them in the STRI Insect Collection."
This collection is the only known vouchered collection of diverse, identified insects and their feeding damage on leaves of identified plant hosts.
The number of collected insect species correlated strongly with the number of damage types recorded in canopy leaves of 24 tree and liana species observed in the feeding experiments. This suggests that the number of types of damage seen in the fossil record is also related to the actual diversity of damage-making insects.
The researchers also compared the modern leaf data to fossil data from Colombia, Argentina, the Great Plains and the Rocky Mountains. They found that the distribution of chewing marks was the same across both modern and ancient settings, showing a striking consistency in how insects have divided up their leaf resources since at least the end of the age of dinosaurs.
"In the fossil record we frequently find a decrease in damage-type richness during cooling events and after extinctions and an increase in damage-type richness during warming events and post-extinction recovery," said Wilf. "Usually, insect body-fossils from these critical time intervals are absent or very rare, so we rely on the insect-damaged leaves to tell the story. These fossil studies have been considered tremendously important for understanding how ecosystems have responded, and will respond, to climate change and disturbance. We now have direct observational evidence that the fossil data represent changes in actual insect richness and no longer need to infer this through deduction alone."
"This work also unlocks the potential to use insect damage as a new way to assess living insect richness, as in the fossil record, in the context of climate change," said Carvalho. "We used fossils to frame a hypothesis about how the world works, today and through time, and discovered in the living tropical rainforest that the hypothesis is correct. More kinds of chewing marks means more kinds of insects."
Other researchers on this project were Héctor Barrios, Programa de Maestría en Entomología, Universidad de Panamá; Donald M. Windsor and Carlos A. Jaramillo, Smithsonian Tropical Research Institute, Panamá; Ellen Currano, assistant professor of geology and environmental earth science, Miami University of Ohio; Conrad C. Labandeira, department of paleobiology, Smithsonian Institution and department of entomology, University of Maryland.
The David and Lucile Packard Foundation and the National Science Foundation supported this research.
A'ndrea Elyse Messer | Eurek Alert!
IU-led study reveals new insights into light color sensing and transfer of genetic traits
06.05.2016 | Indiana University
Thievish hoverfly steals prey from carnivorous sundews
06.05.2016 | Staatliche Naturwissenschaftliche Sammlungen Bayerns
Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.
Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly...
If a person pushes a broken-down car alone, there is a certain effect. If another person helps, the result is the sum of their efforts. If two micro-particles are pushing another microparticle, however, the resulting effect may not necessarily be the sum their efforts. A recent study published in Nature Communications, measured this odd effect that scientists call “many body.”
In the microscopic world, where the modern miniaturized machines at the new frontiers of technology operate, as long as we are in the presence of two...
Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.
Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...
Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.
In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...
Honeycomb structures as the basic building block for industrial applications presented using holo pyramid
Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...
27.04.2016 | Event News
15.04.2016 | Event News
12.04.2016 | Event News
06.05.2016 | Earth Sciences
06.05.2016 | Life Sciences
06.05.2016 | Life Sciences