About those Extra and Missing Frog Limbs….

Remember how concerned we all were about frog limbs? Answers!:

In the late 1980s and early 1990s, researchers started getting reports of numerous wild frogs or toads being found with extra legs or arms, or with limbs that were partly formed or missing completely.
The cause of these deformities soon became a hotly contested issue.
Some researchers believed they might be caused naturally, by predators or parasites.
Others thought that was highly unlikely, fearing that chemical pollution, or UV-B radiation caused by the thinning of the ozone layer, was triggering the deformations.
“Deformed frogs became one of the most contentious environmental issues of all time, with the parasite researchers on one side, and the ‘chemical company’ as I call them, on the other,” says Stanley Sessions, an amphibian specialist and professor of biology at Hartwick College, in Oneonta, New York.
“There was a veritable media firestorm, with millions of dollars of grant money at stake.”

Somehow, the voices of the latter group were much more prevalent in the media than the former. (Surprise!). Well, the mystery of the missing legs was resolved a few years ago (what, you didn’t know?). Just like we all thought, it was we humans who were to blame…..!:

Sessions and other researchers established that many amphibians with extra limbs were actually infected by small parasitic flatworms called Riberoria trematodes.
These creatures burrow into the hindquarters of tadpoles where they physically rearrange the limb bud cells and thereby interfere with limb development.

Er…oh. OK, but what about all of those poor three-limbed frogs. Surely we did it to ’em!

The mystery of what causes frogs to have missing or deformed limbs remained unsolved until Sessions teamed up with colleague Brandon Ballengee of the University of Plymouth, UK….While surveying, Ballengee also discovered a range of natural predators he suspected could be to blame, including stickleback fish, newts, diving beetles, water scorpions and predatory dragonfly nymphs.
So Ballengee and Sessions decide to test how each predator preyed upon the tadpoles, by placing them together in fish tanks in the lab.
None did, except three species of dragonfly nymph.
Crucially though, the nymphs rarely ate the tadpoles whole. More often than not, they would grab the tadpole and chew at a hind limb, often removing it altogether.
“Once they grab the tadpole, they use their front legs to turn it around, searching for the tender bits, in this case the hind limb buds, which they then snip off with their mandibles,” says Sessions.

Hm. So bugs eat frogs. Payback is a b$%#&! I wonder if there are other environmental claims out there that could use some further research?

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14 years ago

We have also noticed that bible thumping politicians usually feed their constituents on Republican clap trap, traumatising them with a mixture of scripture and family values while stuffing their gullets with cash and enough adulation so that they are reelected by their somnambulent victims.
Let’s all repeat, “Our leaders are the finest men, and we elect them again and again.”
This peculiar parasite is usually found in the South, tends to belong to the chamber of Commerce, and is usually, though there are a few notable exceptions, a member of the Republican Party. The Republican variety is particularly insidious since it lulls its victims with quotations from the King James Bible and then proceeds to devour them. Can I have an amen and your trust and your vote.

14 years ago

Good story Marc. I’m sure there are other similar stories regarding research be it scientific, environmental or medical and the greed for credit and grant money.
And thank you to OTL for clearing things up for us simpletons – that there are two distinct Americas (in the words of John Edwards). The insidious, greedy, bible thumping members or supporters of the Republican variety who joyfully harms their victims — and everyone else who is unselfish and whose judgment and integrity can be trusted. Thank you again for your usual fair and coherent comments.

14 years ago

Interesting post. It should remind all of us about making assumptions based on popular opinion. But I think you have a bigger frog in mind- GLOBAL WARMING !. Msteven’s observation about grants and greed should be remembered, too. But his response and lack of humor to OLT’s comment suggests he fears that his buds may have been bitten off.

14 years ago

” you have a bigger frog in mind- GLOBAL WARMING !”
But those British researchers didn’t go far enough. A little more digging would have revealed that, indeed, man is responsible for the missing limbs. Specifically, two men. Even worse, two Republican men.
Dick Cheney and Karl Rove, convinced that all frogs are Democrats, developed the dragonfly nymph in Rove’s sinister genetic engineering lab. They then TURNED IT LOOSE UPON THE WORLD. [cue evil cackling]
(Good find, Marc.)

14 years ago

You have proven once again that you are too much of a simpleton to profit from information given to average simpletons. Let me try to spell it out for you, I’ll take it v…e…r…y s…l…o …w…l…y. H…e…r e…’…s s…o…m…e…t…h…i…n…g f…r…o…m t…h…e K…i…n…g J…a…m…e…s b…i…b…l…e.
Then spake Jesus to the multitude, and to his disciples,
Saying The scribes and the Pharisees sit in Moses’ seat:

(to help you a bit this means that they, the Scribes and Pharisees, are making the laws. Today that means our elected officials. In other words, and in this instance, the Governor of South Carolina, a Bible belt state).

All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not.
For they bind heavy burdens and grievous to be borne,

Remember, Sanford refused the State stimulus money?

and lay them on men’s shoulders; but they themselves will not move them with one of their fingers.
But all their works they do for to be seen of men:

Except when they’re hiking the Appalachian Trail.


14 years ago

OTL, thanks for the defintive proof that only bible thumping members or supporters of the Republican variety lack integrity. There are certainly no examples found in any other ‘variety’.
You should be very proud of yourself.
B..e v…e…r..y p..r..o..u..d o..f y..o..u..r..s..e..l..f
V..e..r..y c..l..e..v..e..r.

14 years ago

This is my last attempt at tossing pearls before swine.
In my post, I said,

This peculiar parasite is usually found in the South, tends to belong to the chamber of Commerce, and is usually, though there are a few notable exceptions, a member of the Republican Party.

from which remarks you conclude that I have provided,

definitive proof that only bible thumping members or supporters of the Republican variety lack integrity.

The best I can say about such illogical leaps is that you have a rich fantasy life awash in self delusion. OldTimeLefty

14 years ago

If you truly think those two sentences accurately portray our comments then you rule the world of self-delusion. ( er, 2nd to Sanford) But since dealing with you appears to insist on being in another version of reality not to mention fairness, then I’ll be beamed up and apologize for characterizing your initial comment as anything other than non-partisan, reasoned and thoughtfully persuasive.

14 years ago

The study by Ballengee and Sessions puts forward an interesting potential explanation for some types of frog deformities. Unfortunately, their research fails to live up to the media hype; it does not solve the mystery of deformed frogs. In the laboratory, they found that some dragonfly larvae will remove limbs of tadpoles. However, Ballengee and Sessions did not actually test the predictions of the dragonfly hypothesis with rigorous data from the field. For example, a clear prediction of their hypothesis is that as the frequency of dragonfly larvae in wetlands increases, the frequency of missing-limb deformities in those wetlands is also expected to increase. Ballengee and Sessions did not test this prediction. Testing such predictions is a fundamental component of science. Until there are well-designed studies that examine the relationship between dragonfly density and frogs with missing limbs in nature, the relative importance of the role of predation in amphibian deformities will remain unknown.

14 years ago

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