Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: thedoc on 20/10/2013 12:08:56
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Blood from the last meal consumed by a mosquito 46 million years ago has been identified inside a fossilised mosquito found in Montana.
Read the whole story on our website by clicking here (http://www.thenakedscientists.com/HTML/news/news/1000350/)
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http://www.thenakedscientists.com/HTML/news/news/1000350/
It's Sunday :)
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Well I'll be damned! Mosquitoes eat blood! Who would have thought it? Not, apparently,
Dale Greenwalt and his colleagues at Washington DC's Carnegie Institution
who spent a fortune discovering what everyone else in Washington DC knows.
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Of course, the article discusses finding iron (hemoglobin) in the blood, not dino DNA, so we may have to wait a few more years for Jurassic Park.
In fact, if the mosquito had blood & hemoglobin in it when it became trapped in amber, then the iron would not be able to escape. So the cells could decompose while the iron remained more or less in place. Not to mention, of course, that mammalian RBC's don't contain DNA.
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Yee-haw! Them folks down DC way done gone an' found iron in hemoglobin! Who says good ole America is a bit slow on the uptake? Where's ma dang banjo?
Seriously, though, chaps, we are still frightfully grateful for all that stuff in the 1940's, even if you did turn up late and claim all the credit, as usual.
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Proving the mosquito had blood in it would be the fist step for later looking for foreign blood components in the mosquito, especially if it can be proven with a non-destructive method.
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Somehow I doubt that even an American mosquito would survive for long by eating its own blood.
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I think insects have hemocyanin, while mammals & birds have hemoglobin.
That is why insects give you such nice pretty colors when splattered on the windshield.
Assuming mosquitoes also have hemocyanin, then the difference between the hemocyanin and hemoglobin would make an easy way to distinguish between ancient mosquitoes that have eaten animal blood, and those that haven't. I assume the technique in the article has also been tested on modern insects.
Oops,
Maybe it is Hemolymph (http://en.wikipedia.org/wiki/Hemolymph), and may not be used for oxygen transport. Nonetheless, one would be more likely to find copper ions than iron ions in insect blood.
One still would need to know how long the iron stays in the mosquito bodies after they've had a nip.
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I thought I would look up iron in mosquitoes (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2329577/). About 87% of the iron is excreted. However, the remaining iron is distributed to the eggs, and other tissues in the mosquito.
Even fruit flies have some iron in their bodies.
So, having a little detectable iron may not indicate fresh ingested blood, although having a heavy load of iron may indicate fresh blood. Or, at least blood that was fresh when the mosquito died.
A control study would help with determining actual proportions.
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Good questions, Clifford; actually, the way they did this experiment (as described in the PNAS paper) was to compare the signals from male and female mosquitoes, reasoning, quite reasonably, that the male (which doesn't consume blood) reflects ion and atomic species signals intrinsic to the insect, while any differences to the engorged female must reflect what she's eaten. They state the relative abundances of the iron and porphyrin signals in the paper. The female has about 8 times more iron coming up.