DISAMPING KANAN INI.............
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Leaf
chewing links insect diversity in modern and ancient forests
Date:
May 2, 2014
Source:
Penn State
Summary:
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 scientists
.....................
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 PLOS ONE.
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 MaestrÃa en
EntomologÃa, 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.
Story
Source:
The above
story is based on materials provided by Penn State. The original article was written by
A'ndrea Elyse Messer. Note: Materials may be edited for content and length.
Journal
Reference:
- Mónica R. Carvalho, Peter Wilf, Héctor Barrios, Donald M. Windsor, Ellen D. Currano, Conrad C. Labandeira, Carlos A. Jaramillo. Insect Leaf-Chewing Damage Tracks Herbivore Richness in Modern and Ancient Forests. PLoS ONE, 2014; 9 (5): e94950 DOI: 10.1371/journal.pone.0094950
Cite This
Page:
Penn State. "Leaf chewing links
insect diversity in modern and ancient forests." ScienceDaily.
ScienceDaily, 2 May 2014.
<www.sciencedaily.com/releases/2014/05/140502172103.htm>.