Quote of the moment: Jonathan Weiner’s Pulitzer-winning explanation of mosquitoes developing immunity to DDT

April 30, 2010

When evolutionists study these worldwide resistance movements, they see four classes of adaptations arising, because an insect under attack has four possible routes to survival.

Jonathan Weiner, author of The Beak of the Finch

Jonathan Weiner, author of The Beak of the Finch, a story of evolution in our time

First, it can simply dodge. Strains of malarial mosquitoes in Africa used to fly into a hut, sting someone, and then land on the hut wall to digest their meals. In the 1950s and 1960s health workers began spraying hut walls with DDT. Unfortunately in every village there were always a few mosquitoes that would fly in through the window, bite, and fly right back out. Millions of mosquitoes died, but these few survived and multiplied. Within a short time almost all of the mosquitoes in the villages were hit-and-run mosquitoes.

Second, if an insect cannot dodge, it can evolve a way to keep the poison from getting under its cuticle. Some diamondback moths, if they land on a leaf that is tainted with pyrethroids, will fly off and leave their poisoned legs behind, an adaptive trick known as “legdrop.”

Third, if the insect can’t keep the poison out, it may evolve an antidote. A mosquito species called Culex pipiens can now survive massive doses of organophosphate insecticides. The mosquitoes actually digest the poison, using a suite of enzymes known as esterases. The genes that make these esterases are known as alleles B1 and B2. Many strains of Culex pipiens now carry as many as 250 copies of the B1 allele and 60 copies of the B2.

Because these genes are virtually identical, letter by letter, from continent to continent, it seems likely that they came from a single lucky mosquito. The mutant, the founder of this particular resistance movement, is thought to have lived in the 1960s, somewhere in Africa or Asia. The genes first appeared in Californian mosquitoes in 1984, in Italian mosquitoes in 1985, and in French mosquitoes in 1986.

Cover of Jonathan Weiner's book, The Beak of the Finch, a story of evolution in our time

Finally, if the insect can’t evolve an antidote,it can sometimes find an internal dodge. The poison has a target somewhere inside the insect’s body. The insect can shrink this target, or move it, or lose it. Of the four types of adaptations, the four survival strategies, this is the hardest for evolution to bring off — but [entomologist Martin] Taylor thinks this is how Heliothis [virescens, a cotton boll-eating moth] is evolving now.

“It always seems amazing to me that evolutionists pay so little attention to this kind of thing,” says Taylor. “And that cotton growers are having to deal with these pests in the very states whose legislatures are so hostile to the theory of evolution. Because it is evolution itself they are struggling against in their fields each season. These people are trying to ban the teaching of evolution while their own cotton crops are failing because of evolution. How can you be a creationist farmer any more?”

Jonathan Weiner, The Beak of the Finch, a story of evolution in our time, Alfred A. Knopf 1994, pp. 254-255. The book won the Pulitzer Prize for general non-fiction in 1995.


DDT nutcases

April 11, 2009

It’s spring, and nutcase fancies turn to thoughts of slandering Rachel Carson and making unholy noises toward environmentalists.

Here’s one nutcase who engages in that peculiar nutcase practice of completely rewriting posts of commenters — claims to be Graeme Bird; is he really running for office?  His claim is that lack of DDT is causing the spread of dengue in Queensland, Australia.  He won’t be swayed by reason or fact (of course — his avatar is a photo of confirmed liar Joe McCarthy).  He asks “how many have died,” but is unhappy with the official answer (one, but that’s not clear — an older woman in poor health).  Nor does he appear to have any sense of irony that drought-stricken Australia has a plague of mosquitoes due to recent rains.  Nor does he appear to understand that dengue is an imported disease in Australia, imported by a traveler, it appears.

Australian officials ask people to drain water from pots, old tires (“tyres” downunder), rain gutters, or any other small pool, which is where the vector mosquitoes breed and mature.  The nutcase appears unfamiliar with the concept of simply preventing the mosquitoes from breeding, in his rush to poison Australia.  Nor do alternative effective techniques for fighting the disease appear to be on his radar.

Alas, there are a lot of these lone nutcases loose.  Watch for updates here for a week or so.

I wonder if it’s a virus that makes them censor any fact or opinion contrary to their own, or whether they simply are complete cranks.  I mean, even Bush’s Secretary of the Interior Dirk Kempthorne got  DDT right.

(Bird’s blog is on WordPress, which will automatically post a link from this post to his blog.  Anyone want to wager on whether he has enough cojones to let the trackback stand?)


Mosquitoes eat DDT, and here’s how

June 18, 2008

University of Illinois researchers found the protein that allows mosquitoes to metabolize DDT.

It’s good news in mosquito research, and may someday provide some insight into how to kill mosquitoes that seem to be resistant to DDT.

But, for all those DDT advocates out there, isn’t this rather embarrassing? Here these researchers have discovered the molecular level mechanisms for a process that the DDT apologists claim doesn’t happen. Oops. Rachel Carson proven right, once again.

There they are, caught red- and bumpy-handed.

Press release text from the University of Illinois below the fold.

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Don’t look now: Businesses ask Uganda to block DDT spraying

March 27, 2008

News comes out of Kampala that the delay in implementing the use of DDT in a Rachel Carson-approved program of integrated pest management — for indoor residual spraying only — faces strong opposition.

From environmentalists? No, you’ll recall that Environmental Defense, the group that led the fight for a ban on broadcast use of DDT in the U.S. has been pressuring the Bush administration and others to use DDT appropriately for years.

The opposition comes from Uganda businesses.

“Zero tolerance on DDT spraying is the feeling of the private sector. Even at the East African Community DDT is a condemned chemical. Government should look for other alternatives,” Mr David Lule, the managing director of Hortexa, a horticultural exporting association to the EU [European Union], said.

Don’t look for corrections or apologies from the pro-poison lobbyists yet. Junk “scientist” Steven Milloy, the “Competitive Enterprise Institute” (which claims to represent businesses) and others have yet to correct any of the many errors they’ve made in their slash-and-burn campaign for poisoning Africa. Why would they change now?

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