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!
New Model of T Cell Activation
27.05.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau
Fungi – a promising source of chemical diversity
27.05.2016 | Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie - Hans-Knöll-Institut (HKI)
A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.
The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...
Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.
The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...
In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.
In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...
Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices
Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.
When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene
In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...
24.05.2016 | Event News
20.05.2016 | Event News
19.05.2016 | Event News
27.05.2016 | Awards Funding
27.05.2016 | Life Sciences
27.05.2016 | Life Sciences