CONGRATULATIONS!
Remember just a few minutes ago when I warned you thusly?
Well, you chose to ignore my advice, and so you've just made a fool of yourself, because there's NOTHING WRONG with the peppered moth example, and the link I gave you explains at length why Wells has his head up his butt when he claims there is. Here's what you neglected to read before you shot your mouth off (DESPITE my clear warning to you and link to the information):Friendly warning: If you've made the mistake of reading Wells "Icons of Evolution" anti-evolution book -- and *believing* it -- you need to read these before you attempt to respond: Icons of Evolution FAQs . They document just how wildly off-base (and how much of a *documented FRAUD*) Wells himself is in his bizarre accusations. Don't say I didn't warn you.
Chapter 7: Peppered Moths
So many things are wrong with Wells's treatment of peppered moths (Biston betularia) that it is hard to list them all; but I will try. The authoritative reference on this topic is Michael Majerus' 1998 book Melanism: Evolution in Action. This book includes two long chapters on Biston. The first chapter, "The peppered moth story," recounts the basic story of melanism in Biston, and relates how this story was pieced together by Kettlewell and others. The second chapter, "The peppered moth story dissected," gives a thorough critical review of the basic story, considering aspects and details of the basic story in the light of research (by Majerus and others) post-dating Kettlewell.
Crucially, however, Majerus clearly and explicitly concludes that, in his view, Kettlewell got things basically correct. At the beginning of his second peppered moth chapter, Majerus writes,
First, it is important to emphasize that, in my view, the huge wealth of additional data obtained since Kettlewell's initial predation papers (Kettlewell 1955a, 1956) does not undermine the basic qualitative deductions from that work. Differential bird predation of the typica and carbonaria forms, in habitats affected by industrial pollution to different degrees, is the primary influence of the evolution of melanism in the peppered moth (Majerus, 1998, p. 116).
Majerus is so clear on this point that one suspects that he was anticipating that his critique would be misinterpreted by non-peppered moth researchers. It seems that there is a "too good to be true" quality about the peppered moth story that leads people to interpret any hint of criticism as a sign that the whole basic story is crashing down. Scientists are by no means immune to this tendency, and indeed they may be more prone to it given the regularity with which popular ideas have been overturned throughout the history of science. The press has an even greater tendency towards snap judgements and oversimplifications when it comes to scientific discussions. Antievolutionists, on the other hand, have always been stuck muttering "it's just microevolution within a species." While this is true, the rapidity and obvious adaptiveness of the change effected by natural selection still seemed to give antievolutionists discomfort. Therefore, it is understandable that when Wells and his fans sniffed a scientific controversy over peppered moths (in truth it was a fairly marginal kind of controversy), they blew things way out of proportion.
- First, several of Wells's worst distortions must be dealt with directly.
The natural resting locations of peppered moths -- Majerus' data. On page 148, Wells discusses the natural resting places of peppered moths, under the heading "Peppered moths don't rest on tree trunks." But they do, at least sometimes. Here are the relevant datasets, which Wells does not quote or cite for his readers:
For further discussion, see below and endnote 4.
Peppered moth photographs, staged and otherwise. Wells raises a fantastic stink about the fact that the photographs of peppered moths in textbooks, showing light-colored typicals next to dark-colored melanics on differing backgrounds, are staged. But the point of such photos is not to prove the truth of the 'classic' story, it is to illustrate the relative crypsis of moth morphs on different backgrounds. Those who feel that their innocent faith in insect photography has been betrayed should consider the fact that most photos of insects in textbooks are probably staged; insects are, after all, small and difficult to photograph. The facts that peppered moths are sparsely distributed and, well, camouflaged also make them difficult to photograph.
But as it turns out, the differences between staged and unstaged photos are minimal. Readers who wish to see unstaged photos of peppered moths are advised to look up Majerus' Melanism: Evolution in Action. Majerus says that all of the peppered moth photos taken by him in the book are unstaged. Readers should consult the figures which are listed below. It may be possible to get permission to include the photos, but until then descriptions shall have to suffice.
(For those with foggy memories of their texbooks, English peppered moths come in three general phenotypic categories: typica, the pale, original 'peppered' form of the moth; carbonaria, the almost black melanic form; and insularia, which includes a range of intermediate-colored moths.)
Figure 6.1 (a), p. 118. Black-and-white photo, edges blurred. A rather dark (almost black) insularia moth, resting apparently on a tree trunk (bark fills the background). The moth is slightly darker than the background.
Figure 6.1 (b), p. 118. Black-and-white photo, middle of moth slightly blurred. A light form of insularia (still more heavily peppered than a typica), resting on a thick tree branch (branch width is about 3/4 that of the moth).
Figure 6.3, p. 122. Black-and-white photo, middle of moth slightly blurred. A typica hanging underneath a hazel twig.
Plate 3, between pp. 146-147, has colored photos. Six photos are shown (the first five are Majerus'), and the captions are quoted, with my comments in brackets.
(a) "Typica and carbonaria forms of the peppered moth on an [sic] horizontal birch branch." [This situation, with two moths close enough together to photograph at once, is very rare, basically only occurring if two moths are meeting to mate.]
(b) "A pair of peppered moths on a twig at dawn. The carbonaria male is much less conspicuous than the typica female." [The carbonaria moth is quite blurry.]
(c) "A carbonaria peppered moth in shadow under a horizontal branch, showing how this positioning may reduce the likelihood of detection." [The moth is being viewed head-on and is indeed difficult to see.]
(d) "Typical form of the peppered moth at rest during the day in hazel foliage." [Head-on view, the moth is hanging underneath a thick twig.]
(e) "An intermediate, insularia form, of the peppered moth." [A 'classic' view, the moth is well-matched to its background, which is apparently tree bark.]
(f) "The non-melanic form of the peppered moth from North America, Biston betularia cognataria (courtesy of Professor Bruce Grant)." [A 'classic' view, the moth is well-matched to its background, which is a lichen-covered surface.]
It should be noted that Majerus is concerned to show his readers aspects of the peppered moth story that they do not get in textbooks; thus the focus on insularia forms and on moths in branches (Majerus is a proponent of the view that peppered moths most commonly -- but not entirely or even almost entirely -- rest on the underside of branches and thick twigs in the forest canopy). Even so, there are several photos that show peppered moths, on tree trunks, on more-or-less matching backgrounds. And guess what? These photos look no different than 'staged' photos of moths on tree-trunks. The most 'staged' aspect about a 'staged' photo is that two differing moth forms are shown side-by-side, but Majerus' first two photos from Plate 3 indicate that even this is not impossible. So the entire photo issue is a mountain made of a molehill.
It should also be noted that several (four) of these unstaged photos have some (minor but noticeable) degree of blurring (e.g., part of the moth will be out of focus). Insects in the wild do annoying things like move and fly away, and are often encountered in poor-light conditions, resulting in less-than-perfect photos. As scientific documentation of observations this is unimportant, but flawed photographs are exactly the kind of thing that are avoided in textbooks, and this is precisely why staging insect photos is a common practice for textbooks (as well as things like nature shows).
Summary of Wells's treatment of moth resting places. To review, Wells's primary objection to the peppered moth story was this:
Most introductory textbooks now illustrate this classical story of natural selection with photographs of the two varieties of peppered moth resting on light- and dark-colored tree trunks. (Figure 7-1) What the textbooks don't explain, however, is that biologists have known since the 1980's that the classical story has some serious flaws. The most serious is that peppered moths in the wild don't even rest on tree trunks. The textbook photographs, it turns out, have been staged. (Icons, p. 138)
[Figure 7-1 is on Icons, p. 139; these are drawings by Icons illustrator Jody F. Sjogren; the source photo, if there is one, is not cited. Confusingly, the caption for the figure is not on page 139 but overleaf on page 140. These are not encouraging signs in a book purporting to critique textbooks.]
The discussion thus far has shown that Wells's "most serious objection" to the peppered moth story is completely baseless: first, peppered moths do in fact rest on tree trunks (a significant portion of the time although not the majority of the time, according to Majerus' data). Second, textbook photos are used to show relative crypsis of moth morphs, not to prove that peppered moths always rest in one section of the trees. And third, Majerus himself has taken unstaged photos of peppered moths on matching tree trunk backgrounds, and these are not significantly different than staged photos; this eviscerates whatever vestige of a point Wells thinks that he has.
What are the implications if moths rest most often underneath branches? Leaving aside Wells's frantic attempt to create a problem where none exists, the relevance of moth resting locations for the 'classic story' (natural selection by bird predation) deserves some consideration. Majerus' considered opinion is that peppered moths rest more commonly underneath branches than was previously appreciated, and that if this is true then some quantitative estimates of selection coefficients may need to be adjusted. However, he is quite clear that the basic qualitative conclusions of Kettlewell (that differential bird predation of moth morphs on changing backgrounds is the selective force) do not need to be changed. As Majerus notes, crypsis is still important for moths in tree branches. He even comments directly on this with two of his photos (Plate 3, photos (b) and (c)). And of course, birds are known to (a) fly and (b) feed in forest canopies, so it is very difficult to see why resting on trunks vs. branches would change bird predation in any radical way.
The scientific literature. Having dealt with Wells's "most serious objection," let us turn to Wells's use of the scientific literature. The primary problem is that Wells gives inordinate weight to a few scattered review papers, by biologists who are not major peppered moth researchers [4], that question the standard view (that bird predation on different colored moths on differently polluted backgrounds caused the darkening of moth populations as pollution increased, and that as pollution decreased this process worked in the opposite direction). Their criticisms have been answered by peppered moth researchers (Grant, 1999; Cook, 2000; Grant and Clarke, 2000; Majerus, 2000). And, as pointed out in the introduction, since Wells bases his argument on the idea that the experts are disowning the 'icons' in their respective fields, Wells is falsified if those experts contradict him.
Bruce Grant's review of Wells. American peppered moth researcher Bruce Grant has written many papers on Biston, and has documented the parallel rise and fall in melanic forms of the North American subspecies of the peppered moth. See Grant's webpage [http://faculty.wm.edu/bsgran/] for listed articles. Dr. Grant has kindly given permission to have his comments on the peppered moth chapter of Icons quoted in this article.
To put them in context, the material quoted below is a copy of the correspondence between Grant and a professional colleague who had requested Grant's views on Wells' chapter, originally written February 7, 2001.
Subject: Wells's Chapter on Peppered Moths
Wells's Chapter 7 is pretty similar to his earlier ms. "Second thoughts about peppered moths" that he posted on the web, and published in abridged form in The Scientist. I sent you my comments about that version about two weeks ago. My general reaction to this latest version is about the same. He distorts the picture, but unfortunately he is probably pretty convincing to people who really don't know the primary literature in this field. He uses two tactics. One is the selective omission of relevant work. The other is to scramble together separate points so doubts about one carry over to the other. Basically, he is dishonest.
He immediately launches the claim "that peppered moths in the wild don't even rest on tree trunks" (p. 138). This is just plain wrong! Of course they rest on tree trunks, but it's not their exclusive resting site. He quotes Cyril Clarke's lack of success in finding the moths in natural settings, but he omits mentioning Majerus' data which reports just where on trees (exposed trunks, unexposed trunks, trunk/branch joints, branches) Majerus has found moths over his 34 years of looking for them. Of the 47 moths he located away from moth traps, 12 were on trunks (that's >25%). Of the 203 he found in the vicinities of traps, 70 were on trunks (that's 34%). Based on his observations, Majerus argued that the most common resting site appears to be at the trunk/branch juncture. What is clear from his data is that they sit all over the trees, INCLUDING the trunks. So what? Kettlewell's complementary experiments in polluted and unpolluted woods compared the relative success of different colored moths on the same parts of trees in different areas, not different parts of trees in the same area. It is true that the photos showing the moths on trunks are posed (just like practically all wildlife pictures of insects are) but they are not fakes. No one who reads Kettlewell's paper in which the original photos appeared would get the impression from the text that these were anything but posed pictures. He was attempting to compare the differences in conspicuousness of the pale and dark moths on different backgrounds. Nobody thought he encountered those moths like that in the wild. At their normal densities, you'd be hard pressed ever to find two together unless they were copulating. I have always made a point of stating in photo captions that the moths are posed, and I think textbook writers have been careless about this. But they are not frauds.
On the subject of lichens, no one has questioned their importance more than I have. But what does Wells do with this? He quotes me, but he doesn't include what else I said has happened on the Wirral (p. 147) with respect to the tremendous expansion of birch stands since the enactment of the smokeless zones. Kettlewell, too, argued that peppered moths are well concealed on birch bark (even without lichens). Wells continues (p. 148) to quote my reservations about lichens in Michigan, but, again, he omits any reference to the data I presented in that paper showing the decline, not only in SO2, but in atmospheric particles (soot) which has been established as a factor altering reflectance from the surface of tree bark. So, while I have questioned the importance of lichens, I have not taken this as evidence that crypsis is unimportant. Wells omits this entirely.
Wells continues to bring up the same old arguments about mysterious other factors (yet to be identified) that account for the persistence of typicals in polluted regions, and the presence of melanics in unpolluted locales. He cites papers written back in the 70s about these puzzles. He omits discussing in any sophisticated way the role of migration other than to say "Theoretical models could account for the discrepancies only by invoking migration...." (p.146), as if in desperation we are forced to grasp at straws. Of course migration is important. Majerus actually reviews this point fairly well by comparing the smoothness of clines in melanism between species that are highly mobile (as is Biston), and species that are relatively sedentary. Instead of showing his meaningless map of the UK (Fig. 7-2) to illustrate what he regards as anomalies in the distribution of melanism and lichens, why doesn't he show the before and after comparison from the national surveys by Kettlewell in 1956, and the survey by Grant et al. in 1996. (If you'd like, I can send you a jpg file of the maps I mean.)
Wells also inappropriately uses thermal melanism in ladybirds to suggest, that while no one has shown this in peppered moths (p. 152), industrial melanism can have other causes besides predation. It's not just that there is no evidence for thermal melanism in peppered moths, there is evidence AGAINST thermal melanism based on the geographic incidence of melanism in the UK, the USA, and Europe. There are no latitudinal clines, and no altitudinal clines as one might expect with thermal melanism. Wells knows this, if he actually read my papers. (He cites them, so I should assume he read them.) He also raises the question of larval tolerance to pollutants. There is no evidence for this, either. I have a paper out on this point, but in fairness to Wells, it came out just this past year.
Wells clouds discussions with irrelevancies. For examples he brings up Heslop Harrison (p. 141 and again on p. 151) and the question of phenotypic induction. Wells makes it sound as if most biologists discount induction based on their belief in natural selection (as if it were a popular religious question). The evidence for the Mendelian inheritance of melanism in peppered moths has nothing to do with evolutionary theory; it is based on old fashioned crosses involving over 12 thousand progeny from 83 broods. The Mendelian basis for this character in this species is as well established as is any character in any species. Wells doesn't mention this, yet he cites my review paper where I do bring this up in my criticism of Sargent et al. Induction has nothing to do with industrial melanism, and Wells knows it. Again, selective omissions on the part of Wells.
On page 151 Wells claims Kettlewell's evidence has been impeached. This is nonsense. It has not. But I have argued, that even if it were entirely thrown out, the evidence for natural selection comes from the changes in the percentages of pale and melanic moths. It is this record of change in allele frequency over time that is unimpeachable. It is a massive record by any standard. (I can send a jpg file with graphs, if you'd like.) I have pointed out, and he quotes me, that no force known to science can account for these changes except for natural selection. Yet, he scrambles the ingredients here. He claims (top of p. 153) "...it is clear that the compelling evidence for natural selection that biologists once thought they had in peppered moths no longer exists." Of course the evidence for natural selection exists! That evidence is overwhelming. Wells, by attempting to discredit Ketttlewell's experiments about predation (and clearly there are things wrong with Kettlewell's experiments) doesn't stop at saying we can't be altogether sure about bird predation because of problems with Kettlewell's experiments. No. He says, instead, that the evidence for natural selection no longer exists. This is just plain wrong. He cannot support this sweeping statement, but he spins it into his conclusion by building a case against Kettlewell. This is what I mean about his tactic of scrambling arguments. He wields non sequiturs relentlessly.
I hope this is helpful to you in your review.
Bruce Grant, Professor of Biology, College of William & Mary. February 2001
Michael Majerus' review of Wells. Majerus' views on the peppered moth "debate" were made clear in 1999, during an online fracas on the Calvin evolution listserv. Majerus, who as we have noted wrote the (most recent) book on peppered moths and industrial melanism (Majerus, 1998), was contacted by one of the participants, Don Frack, about the claims of creationists about the peppered moth now being a "peppered myth." The creationists' claims were theoretically based on Majerus' book, Coyne's (1998) review of it, and an article discussing these works and interviewing Majerus and Coyne in the British newspaper The Sunday Telegraph (Matthews, 1999). Majerus' email message was posted to the listserv. Majerus concluded:
Bernard [Kettlewell] was a first rate entomologist and scientist. His experiments were meticulous and generally well designed. In my opinion, many of his experiments were among the best that have been conducted on melanism and bird predation. The 'design flaws' in some of the experiments, if you want to call them that were primarily a result of practical expediency because Kettlewell wanted to be able to see birds taking moths, and to film them. The only real flaw may have been his resting site selection experiments, where he MIGHT (we do not actually know) have used moths from different populations (see pages 142-143).
[...]
The suggestion that Kettlewell ever 'faked' a result is offensive to his memory. He was an honourable, good scientist who reported his findings with honesty and integrity.
[...]
To end, may I put on record to you, that my view is that the rise and fall of the carbonaria form of the peppered moth has resulted from changes in the environments in which this moth lives. These changes have come about as a result on changes in pollution levels which have altered the relative crysis of the forms of this moth. The main, if not the only selective factor that has lead to changes in the frequencies of the forms over time is differential bird predation. The case of melanism in the peppered moth IS ONE OF THE BEST EXAMPLES OF EVOLUTION IN ACTION BY DARWIN'S PROCESS OF NATURAL SELECTION that we have. In general it is based on good science and it is sound.
(Majerus email to Don Frack, posted March 30, 1999. Capitalization original. Available at: http://www.calvin.edu/archive/evolution/199903/0312.html)
Wells was evidently contacted about Majerus' comments. Since Majerus had been Wells's primary source for the claim that the peppered moth was now a "peppered myth," perhaps Wells felt that he had to respond. Wells's response was to move Majerus from the "respected authority" category to the "fraud" category. Frankly, Wells freaks out:
BUT EVERYONE, INCLUDING MAJERUS, HAS KNOWN SINCE THE 1980'S THAT PEPPERED MOTHS DO NOT REST ON TREE TRUNKS IN THE WILD. This means that every time those staged photographs have been re-published since the 1980's constitutes a case of deliberate scientific fraud. Michael Majerus is being dishonest, and textbook-writers are lying to biology students. The behavior of these people is downright scandalous.
I know what I'm talking about. I spent much of last summer reading the primary literature (email me if you want the references). Frankly, I was shocked by what I found -- not only that the evidence for the moths' true resting-places has been known since the 1980's, but also that people like Majerus and Miller continue to deceive the public.
Fraud is fraud. It's time to tell it like it is.
(Wells's message posted to Calvin listserv, March 31, 1999. Capitalization original. Available at: http://www.asa3.org/archive/evolution/199903/0348.html)
In due course, Wells's message made it back to Majerus, who responded with a full-scale dissection of all of Wells's key points:
[...]
Evidence of selective predation in the peppered moth is not lacking. It is just not provided in the quick text book descriptions of the peppered moth. How can it be. I have read some 500 papers on melanism in the Lepidoptera. In total, these papers probably amount to about 8000 pages, and the story is condensed into a few paragraphs in most textbooks for schools. Even in my own book, I could only give a review of the case covering about 60 pages including illustrations.
The older hypothesis that melanism was induced by pollutants was discredited because Heslop [Harrison's] experiments lacked appropriate controls, and his results could not be replicated, despite several attempts. Furthermore, the levels of mutagenesis that he recorded are several times higher than those produced by doses of radiation that induce complete sterility in fruit flies (see E.B. Ford (1964) Ecological Genetics for full critical review).
Finally, I agree with Dr Wells that photographs of two peppered moths staged on backgrounds for effect should say they have been done purely for illustrative purposes. I have many times, in undergraduate lectures, pointed out that photographs of the type that appear in so many text books are faked. However, I would point out that none of the photographs of live peppered moths taken by myself, which appear in the book were staged. All show peppered moths where they were found in the wild.
End-note: It is difficult to have an informed discussion of a complicated ecological system with those who have little or no experience of the system. My advice to anyone who wishes to obtain a fully objective view of this case is to a) read the primary papers that I based my review upon, and any other relevant papers, and b) gain some experience of this moth and its habits in the wild. Of all the people I know, including both amateur and professional entomologists who have experience of this moth, I know of none who doubts that differential bird predation is of primary importance in the spread and decline of melanism in the peppered moth.
I hope that this is some use to you, Donald, and that it encourages more people to look at the case of the peppered moth with an open mind. If it can help interest a few more people in moths and butterflies, that is all to the good.
Best wishes, and Happy Easter.
Mike Majerus
(Majerus email, posted to Calvin listserv by Don Frack, April 5, 1999, bold added. Available at: http://www.asa3.org/archive/evolution/199904/0103.html)Frack says of this,
Note the complete irony of the capitalized sentence. Majerus is the foremost proponent (in the literature I've seen) of the idea that the moths most commonly rest higher in the trees. His data are the only ones I have seen cited as evidence of [what] happens "in the wild." Majerus is attacked as "dishonest" and "text-book writers are lying to biology students", their behavior is "scandalous." [...] If Wells is right, he hasn't demonstrated it here. He attacks both Michael Majerus and Bruce Grant. If Grant's frequent co-authors, such as Cyril Clarke, are added to the ridicule list (and I don't know why they wouldn't be), then Wells is well on his way to rejecting all the well-known researchers on this subject. An awesome, and, at face value, an incredibly arrogant, claim.
There is much more where this came from, and unfortunately there is not yet a comprehensive web source covering Wells's abuse of peppered moths, so you have to do some digging. Some good places to start are these links:
Bruce Grant's review article: http://www.wm.edu/biology/melanism.pdf
Don Lindsay's archive (links to various letters to newspapers from Grant and others, protesting Wells's characterizations of their work)
Wells scored a minor coup when a toned-down version of his essay "Second Thoughts about Peppered Moths" was published in The Scientist (13(11), p. 13, May 24, 1999). A longer, unedited version is here.
The 1999 Wells/Frack posts on the Calvin listserv go roughly in this order (these really should be reformatted and archived somewhere):
Frack, "Peppered Moths - in black and white (part 1 of 2)":
http://www.asa3.org/archive/evolution/199903/0314.htmlFrack, "Peppered Moths - in black and white (part 2 of 2)":
http://www.asa3.org/archive/evolution/199903/0312.htmlWells, quoted in "Peppered moths again":
http://www.asa3.org/archive/evolution/199903/0348.htmlFrack, "RE: Peppered Moths again": http://www.asa3.org/archive/evolution/199903/0378.html
Frack, Peppered Moths - round 2 (part 1 of 2)
http://www.asa3.org/archive/evolution/199904/0100.htmlFrack, Peppered Moths - round 2 (part 2 of 2)
http://www.asa3.org/archive/evolution/199904/0103.htmlFrack, "Peppered moths, round 3":
http://www.asa3.org/archive/evolution/199904/0200.htmlFrack, "Peppered moths and Creationists":
http://www.asa3.org/archive/evolution/199904/0201.htmlWells, "My last word":
http://www.asa3.org/archive/evolution/199904/0204.htmlFrack, "RE: My last word":
http://www.asa3.org/archive/evolution/199904/0207.htmlOf moths and maps. So, the experts disagree with Wells and furthermore identify just the kinds of deceptive tactics that I have been talking about. A further instance is Wells's Figure 7-2 (p. 145), a map of England with four locations marked with letters representing "Discrepancies in peppered moth distribution." This map deserves enshrinement as exhibit A in geographer Mark Monmonier's (1996) book How to Lie with Maps. This is basically what Wells's map looks like:
(After Wells, Icons, p. 145, Figure 7-2. The exact caption is quoted below the figure. My rendition of the border of Great Britain is very crude, being based on the first graphic I could find on the internet, but apart from that Wells's figure is accurately represented. A figure similar to that in Icons can be found in Wells's unedited moth essay, here.)
What Wells did here was dig through the literature and find a few instances where he could find some weak excuse for an observation 'contradicting' what was expected. However, if one inspects real maps by real moth researchers, one finds that the geographic pattern is actually a good match with expectations. Here are the maps that Bruce Grant mentioned in the above-quoted review:
Grant's comments on these maps: "The maps show a before-after comparison of the geographic distribution of melanic phenotypes in peppered moth populations in Britain based on Kettlewell's 1956 survey (left map) and that conducted 40-years later (1996) by my colleagues and me (right map). The black segments of the pie charts indicate the percentage of melanics at the various locations. Clearly melanism has declined everywhere it was once common." (Grant, personal communication, February 11, 2002)
The source publication for these maps: Grant, B. S., Cook, A. D. , Clarke, C. A., and Owen, D. F. 1998. Geographic and temporal variation in the incidence of melanism in peppered moth populations in America and Britain. Journal of Heredity 89:465-471.
Wells's map (Figure 7-2 from Icons) is more fraudulent than all of the textbook moth photos put together.
