Tree resin the key evidence of current and historic insect invasions

Mar 23, 2011

A University of Alberta-led research team has discovered that insects that bore into trees as long ago 90 million years, or as recently as last summer, leave a calling card that's rich with information.

The information is contained in the resin found within trees and on their bark. Resin is produced in large quantities by a tree when it's under attack by .

Normally, to assess if a tree is under an attack from boring insects researchers have sometimes had to rip patches of bark from healthy trees. But now forestry workers looking for the telltale sign of insect borings in tree trunks have a far less invasive method—they can just examine the resin that collects in clumps on the tree trunk.

An attack by boring beetles typically affects trees in two ways. The boring action damages the phloem layer just under the bark, which cuts off the passage of nutrients within the trunk. Also, beetles often introduce a fungus that spreads into the woody xylem tissue of the tree and starves the treetop of water. A side-effect of insect invasion and water stress is a reduction in the tree's ability to absorb carbon dioxide from the atmosphere. Carbon dioxide is necessary for life-sustaining photosynthesis.

The research team, including U of A paleontology graduate student Ryan McKellar, looked for subatomic-sized isotopic evidence that indicates water stress levels in trees as a result of an insect attack.

The team discovered a common marker in carbon isotopes found in the resin of living trees under insect attack and in the fossilized resin or amber produced by ancient going as far back as the age of dinosaurs: they both contain elevated levels of carbon-13.

McKellar's group also found evidence of boring beetles and the increased presence of carbon-13 within amber fossils dating back in the geological record to 90 million and 17 million years ago. The locations are as geographically removed as present-day New Jersey and the Dominican Republic.

With this finding the researchers suggest that two or the world's major amber deposits may have been produced by insect attacks like mountain pine beetle that are seen in modern ecosystems.

This discovery will help researchers understand the history of insect infestations.

Explore further: Biologist reels in data to predict snook production

More information: McKellar's research will be published March 23 in Proceedings of the Royal Society B: Biological Sciences.

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kevinrtrs
1 / 5 (2) Mar 23, 2011
suggest that two or the world's major amber deposits may have been produced by insect attacks like

The researcher/article does not mention the deposits so it leaves the reader hanging.
Question to ask is what is the size of these deposits and just how many beetles does the researcher think it took to produce such huge deposits as globs of 30 pounds of resin?

A far more likely and better explanation of amber deposits is that huge amounts of trees were crushed and pulverised under huge amounts of water to extract those large amounts of amber.

This would also explain the exquisitely encased insects inside globs of amber. One cannot encase an insect in such an intact way slowly over a period of weeks - it has to happen almost instantaneously or else part of the insect will be torn off or rot away. The only way I can think this kind of encapsulation can occur is via sudden compression and washing of resin away from its source into an extraction void. Hot water is ideal for this.
PaulieMac
5 / 5 (1) Mar 23, 2011
The researcher/article does not mention the deposits so it leaves the reader hanging.


New Jersey and the Dominican Republic.

A far more likely and better explanation of amber deposits is that huge amounts of trees were crushed and pulverised under huge amounts of water to extract those large amounts of amber.

This would also explain the exquisitely encased insects inside globs of amber. One cannot encase an insect in such an intact way slowly over a period of weeks - it has to happen almost instantaneously or else part of the insect will be torn off or rot away.


Sheesh... Your attempts at logic are even more laughable than usual. How would the "huge amounts of water" "crush and pulverize" the trees - but leave the insects perfectly intact??

And you do, of course, realise that you can go out to a forest, today, and actually see with your own eyes an insect being trapped and encased in tree resin? It is not in the slightest degree a mysterious process :) lol
Kingsix
5 / 5 (1) Mar 23, 2011
I am not a tree expert, but I imagine that when first produced tree sap is more fluid thus running fairly quickly until it encounters a surfaces to collect and harden on, namely a bug on or under its bark.
Again I am no tree expert, but I do live near a lot of them.