Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
UPDATE: Reader Robin has already submitted a Ceiling-Cat-defaced bill, shown below. Perhaps there should be a contest for the most creative effacement of God. . .
Now I don’t know if this is legal or not, so I’m giving no advice here. Some say that because the law prohibits only marks on bills that render them unfit for circulation, it’s okay, as the bills are still “fit.” On the other hand, I’ve heard that these marks do indeed make them unfit, since they supposedly won’t be accepted by vending machines that scan bills.
Who knows? All I know is that the slogan “In God we Trust”, which Eisenhower made the legal motto of the U.S. in 1956, is starting to irk me. Not only do I not trust God, but I strongly doubt there’s anyone up there to trust.
I’ll close today’s posts with three unrelated photos.
First, Randy Schenck from Iowa has taken pity on the cold squirrels, and build a double feeder in his Iowa home. Squirrels readily nom corn on the cob (dried, I think), and if you fasten the cobs vertically, as shown below, you get a cool feeder. (They also have to stay on the spot instead of absconding with the cobs.) Randy got a special treat when two morphs showed up at once:
This is the feeder in action with the Eastern Grey Squirrel (Sciurus carolinensis) and the Melanistic version as well.
Second, here’s dollar I received from a reader, who sent it to demonstrate the new slogan. I want a stamp like that!
And, speaking of cobs, here’s a tw**t from our own Matthew Cobb detailing the progress of his new kitten, still unnamed. I gather that “Mark Ing” is some kind of British academic joke. After seeing the kitten’s whole body, I think the name “Spot” is appropriate.
UPDATE: According to the Deutsche Welle, a German author of Egyptian origin has gone into hiding after getting death threats. His name and crime?
The news of the death threats against Abdel-Samad was announced by his publisher on Tuesday.
“Hamed Abdel-Samad is taking the call for him to be murdered seriously and has gone into hiding,” the head of the Munich-based Droemer Knaur publishing house, Margit Ketterle, said in a statement.
The calls for the author to be killed apparently came after a speech he gave in Cairo last week in which he criticized radical Islam and Egypt’s Muslim Brotherhood, accusing them of spreading “religious fascism.”
Abdel-Sadam reportedly also said he did not intend to insult Islam but had a right to express his views.
Not according to some Islamists.
Numerous Islamist web sites subsequently published a picture of the author with the words “wanted dead” written above.
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America has its share of conspiracy theorists, but they’re far more prevalent in the Middle East, at least when it comes to Israel. There is no Muslim brutality, it seems, that can’t be blamed on Israel. The latest is the attacks on the Charlie Hebdo staff and people in a Paris kosher grocery store, which nobody with any brains doubts were a). committed by Muslim terrorists and b). were, at least according to the terrorists’ own statements, motivated by religiously-based ire of the depiction of Muhammad and animus towards Jews.
But that sensibility doesn’t extend to Palestinians, who are, for crying out loud, blaming the Paris violence on Israel, particularly Mossad, the Israeli secret service. (Remember that many Palestinians also thought that the 9/11 attacks were a conspiracy by Zionists. Even the supposed “myth” of the Holocaust was supposed to be orchestrated by Jews.)
Now you may want to question this poll simply because it was reported by Palestine Media Watch, but it was in fact conducted and originally published by an official organ of the Palestianian Authority (PA):
Following the terror attacks against the Charlie Hebdo magazine and a Jewish store in which Muslim terrorists killed 17 people in France earlier this month, columnists writing for the official Palestinian Authority daily Al-Hayat Al-Jadida have claimed that Israel was behind the attacks.
This view is shared by the vast majority of Palestinians, according to a poll conducted by Ma’an (an independent Palestinian news agency). The poll found that 84.4% support the claim that “the operation (i.e., terror attack) was suspicious, and that Israel may be behind it,” while “only 8.7% believed that the murder of the French [citizens] in Paris was a natural result of the spread of Islamic extremism in Europe.” [Ma’an, Jan. 19, 2015]
Why would Mossad or Israel try to murder Jews in France, you ask? Why, to get French Jews to emigrate to Israel! Or so says the same organ (as reported by PMW):
The writers of the official PA daily have argued that Mossad, the Israeli Secret Intelligence Service, planned the attacks because Israeli PM Benjamin Netanyahu and other Israeli leaders want to encourage Jewish immigration and take “revenge on European governments… because of their… support for… an independent Palestinian state.” [Al-Hayat Al-Jadida, Jan. 15, 2015] (Longer excerpts of all quoted articles appear at the link].
Here’s a bit more Holocaust denial, from a debate that took place five days ago on the Arabic channel of Al-Jazeera (from Qatar), that supposedly “objective” news source. It was translated and put up by the Middle East Media Research Institute (MEMRI), which describes it as follows:
The U.S.-based Egyptian author Magdi Khalil and Tunisian scholar Shakir Al-Sharafi recently clashed in a heated TV debate on freedom of speech, following the January 2015 Paris attacks. “The Jewish Holocaust is an indisputable and irrefutable fact,” said Khalil. “Why is it only the Muslims who deny the Holocaust?” Al-Sharafi, for his part, cited French Holocaust denier Roger Garaudy, said that Germany and Europe were still “paying the price for this imaginary Holocaust, and added that the Charlie Hebdo attack had been a conspiracy, filmed in advance. The debate aired on Al-Jazeera TV’s show “The Opposite Direction” on January 20, 2015.
Click on the screenshot to hear the heated exchange:
Putting a debate like this on television, at least on a station like Al-Jazeera, is like having a televised debate between creationism and evolution. Evolution, like the Holocaust, is indisputable. And Magdi Khalil is a brave man to say stuff like this. Even though he lives in the U.S., remember that Ayaan Hirsi Ali does, too, and she has bodyguards.
The Iowa “Freedom Summit,” a conclave of Republicans who aspire to either the party’s Presidential nomination in 2016 or simply the limelight, turned out to be a Confederacy of Dunces. Even for Republicans, they were markedly insane. And the craziest of them all was, of course, Sarah Palin, who talked for 35 minutes and said nothing beyond “Love the Flag,” “Hate Obama” and “Make Change!”
Here’s a video of her speech, which got a standing ovation (that tells you something about Republicans, too). If you can’t stand watching the whole thing (I did, but I was also reading and drinking a nice Pinot), just watch after 29:00, for she really goes off the rails at 29:30. That means you’ll only have to watch about six minutes.
But I urge you to watch the whole thing—for same reason that you sniff the milk when you know it’s gone bad. But really, it will make you realize how batshit insane Republicans are. They love this woman!
The highlights for me were her counterfactual claims that Republicans are the ones who really care about the middle class, while Obama and the Democrats don’t. Add to that the assertion (at 19:47) that Republicans also care deeply about women, while Democrats oppress them. She sprinkles her breathy lucubrations with sarcastic references to “The Media,” clearly ticked off that they told the truth about her lack of neurons. But the best reason to listen is simply that it’s so entertaining. If you can ignore her odious politics, it sounds like an extended skit on Saturday Night Live. Just listen to the first two minutes and see if you don’t get hooked.
On behalf of my country, I apologize to all foreigners for the popularity of Sarah Palin.
Finally, click on the screenshot below to get Jon Stewart’s rib-tickling take on the whole Freedom Summit.
I’ve posted a lot about morphological mimicry in animals: the evolved resemblance of one species’ appearance to that of another, or to the environmental background. This mimicry can serve to protect animals from being spotted by predators, or, if you’re a predator, to hide yourself from your prey.
The latter situation, in which animals resemble something else so they can kill or injure members of another species, is called aggressive mimicry. And an intriguing new example of this is reported in a paper in The Proceedings of the National Academy of Sciences by Adrián Salazar and six colleagues (free download, reference below). The mimicry, however, involves chemistry rather than appearance. In the new case, an aphid has evolved to secrete the hydrocarbons that are on the surface of larvae of an ant with which the aphid is normally associated. This mimicry deceives the ants, who can’t see very well but are sensitive to chemical signals. The ants then carry the aphids into the nest and deposit them in the brood chamber, whereupon the duplicitous aphids pierce the larvae with their mouthparts and suck out the hemolymph.
The story is actually quite complex, so I’ll leave out a lot. The aphid, Paracletus cimiformis, is found mostly in Europe but also in Asia and North Africa. It lives on the roots of plants, and, to make matters complicated, is associated with several species of ants. The one studied by the authors is Tetramorium semilaeve, common in Spain, where the research took place. Further, the life cycle of the aphid, as with most aphids, is very complicated, as it successively alternates between two plants hosts, the turpentine tree and grasses. On top of that, the aphids can exist as either winged or wingless forms, and as both sexual and asexual forms. The asexual ones reproduce parthenogentically: unfertilized but diploid eggs (produced without the normal meiotic cell division) are produced by the mother, kept inside her body, and then the young aphids are born alive. The offspring are thus clones of the mother.
Finally—and most important for our purposes—the aphids have two interesting features. The first is that the adults on the grasses (their “secondary” host) come in two forms, a flat whitish form (I’ll call it “flat”) and a more rounded, olive-green form (I’ll call it “round”). These differences are apparently not genetic: white aphids can produce green offspring and vice versa, probably depending on the environmental conditions experienced by the parent and offspring. (Note, though, that the program permitting such switches is undoubtedly coded in the aphid’s genes.)
And those two forms do different things. The round green aphid is a mutualist with the ant: it is trophibiotic, which means in this case that the aphids, after sucking the plant sap, secrete honeydew out of their butts, and the ants eat it. In return, the ants provide the aphids with protection from predators. This is thus a mutualism, a behavior of a pair of species in which both benefit from their relationship (a famous example are lichens, which are actually mixtures of algae and fungi that help each other).
The flat aphid is the one that chemically mimics the ants’ brood, gets carried into the nest, and sucks the hemolymph (insect “blood”) out of the ant larvae. (It’s not yet clear whether the ant larvae are actually killed or just donate a bit of blood, but the researchers did find ant DNA in the flat aphids, and watched them attack the larvae.) That is regarded as aggressive mimicry, and can be seen as either parasitism or predation on the ants. So the aphids have a complex mixture of wingedness and winglessness, sexual and asexual reproduction, living on either trees or grasses, and forming either mutualistic round forms or predatory white forms. (These forms are called “morphs”.) This diagram below shows the complexity; I’ve added the caption from the paper as well. You can ignore all of this except for the round and flat forms on the right:
Fig. 1. Simplified diagram of the biannual life cycle of P. cimiciformis. Sexual reproduction takes place on P. terebinthus trees, its primary host, where up to five different morphs occur. Of these generations, three develop inside distinct galls that they induce in their host’s leaves. Toward the end of summer, the last generation born inside the galls consists of winged aphids that fly to the roots of several gramineous species, its secondary host. There, they initiate a succession of root-dwelling wingless parthenogenetic generations consisting of two morphs: the round (RM) and the flat (FM) morphs, respectively. These two morphs participate in mutualistic associations with ants of the genus Tetramorium. In summer, two winged morphs may appear. One disperses the clone to new grasses whereas, in regions where P. terebinthus is present, a second winged morph will fly back to the primary host to give birth to the sexual morphs. Afg, apterous fundatrigeniae; E, eggs; Fx, fundatrix; M, male; Sf, sexual female; Sxp, sexuparae; Wfg, winged fundatrigeniae; Wvg, winged virginoparae. The question mark denotes unclear phenology details during the root-dwelling phase (SI Text and Fig. S1).
Below is a photo of the ants and aphids. Panel A shows the ants waving their antennae at the round green form, which is a signal for the aphids to excrete honeydew for the ants to eat. Observations show that waving occurs only with the round form, followed by antennal tapping of the aphid’s butt when it excretes honeydew. The flat aphids are never waved at by ants, but only tapped, a behavior called “antennation.”
Panel B shows the flat white aphids in the brood chamber among the ant larvae (arrows show the aphids, which resemble the brood). Panel C shows the white form sinking its rostrum (the sucking apparatus) into a juicy ant larva, getting ready to suck out the larval hemolymph. Panel D shows a larva leaking hemolymph (the bubble) after being attacked:
The authors tested the hypothesis that the flat white aphids had something about them besides appearance that deceived the ants into thinking they were brood (it wasn’t appearance, for the flat and round aphids are treated differently even in complete darkness). The obvious hypothesis is “chemical mimicry.” So they first showed, using gas chromatography, that the hydrocarbon profile of the flat white aphids was more similar to that of the ant larvae than to the profile of round green aphids.
Virtually all insects have a layer of hydrocarbons on their cuticle; these normally act to prevent desiccation and also act as chemical signals. I worked on this in Drosophila for several years, and showed that different species discriminate against each other when the males “taste”—using chemoreceptors on their forelegs—the hydrocarbons on the females prior to mating. And you can change that discrimination by transferring hydrocarbons between females of different species, something I discovered you can do by simply crowding a female of one species with a gazillion females of another. (I called this the “Tokyo subway experiment”.) The “target” female gets a lot of the foreign hydrocarbons rubbed off onto her body, which affects how males court her.
First, here are the hydrocarbon profiles (a readout from a gas chromatrograph) of the two forms of aphids and the ant larvae. An analysis of the composition (the cuticle contains many hydrocarbons) shows that the flat aphid is more similar to the ant larva than either is to the round aphid, something shown on the right. The differences between aphid morphs isn’t simply due to their acquiring hydrocarbons from ant larvae by contact, for the differences persist when aphids are raised in the lab without any contact with ants.
Finally, the authors tested whether the hydrocarbon differences had any significance for the ants’ behavior. They did. This experiment was done simply by impregnating dummy aphids with extract from either ant larvae, flat aphids, round aphids, or the hexane solvent used to extract hydrocarbons (the control). Ants not only tapped the dummies more when they were impregnated with ant-larval or flat-aphid extract than with round-aphid extract, but only the dummies impregnated with round-aphid extract were waved at. Further, only the dummies impregnated with ant-larval or flat-aphid extract were carried into the nest; this never happened with control dummies or those carrying round-aphid extract. (There are some problems with the statistical significance of these behaviors, so the results are more suggestive than definitive.)
The chemical profiles, as well as the ants’ behavior, suggest that the flat morph has evolved to deceive the ants. This appears to be a derived condition, for all the related aphids we know about have only the mutualistic and round honeydew-excreting form.
This raises several questions. I’ll mention only two. First, how did this evolve? Although the flat and round forms are apparently genetically similar, with the difference controlled by some environmental cue (which cue is another question), the genetic program that causes an aphid to become either round or flat is in the aphids’ genome, a program triggered in one direction or another by environmental cues. The program and environment-sensitive switch are certainly the product of natural selection. But how the flat form evolved from the white form, while both continue to coexist, is a mystery, and we don’t know a lot about how other aspects of aphids’ complex life cycle evolved. There are multiple genetic programs in this aphid (flat vs. round, sexual vs. asexual, winged vs. wingless, tree-dwelling vs. grass-dwelling), and it boggles the mind to consider how they could have evolved. (I suppose the Discovery Institute will use our ignorance to cry “God designed it!”)
Second, what keeps both forms of aphid present in a single population? One obvious answer is a kind of “frequency-dependent selection”. That is, although the differences between flat and round are based on environmental cues, the genetic program has probably evolved to respond to those cues in an adaptive manner, producing different forms when they are most adaptive. One theory, which is mine, is that when the flat forms get too numerous, the round ones have an advantage because the ants’ brood will be diminished so severely that the colony may go extinct, endangering the survival of all aphids associated with the colony. This becomes more probable when many aphids are clones, because selection on one is selection to precisely the same degree on clone-mates.
Conversely, when there are lots of round aphids, there may be an advantage to avoiding competition by producing the flat form that occupies a completely different feeding niche.
These advantages depend on the relative frequency of the two forms, which is why it’s called frequency-dependent selection. (This is selection operating not on the genetic program that codes for the two different appearances and behaviors, but on the genetic program for determining when aphids switch from one form to another. In other words, the dependence of the adaptive values of roundness or flatness on the frequency of these two types has tuned the genetic “switch” to be flipped in response to changing frequencies.)
Finally, one can contemplate the difference in evolutionary strategies of the two forms, one mutualistic and the other parasitic. But here I’ll simply reproduce what the authors say:
The dual strategy developed by the aphid P. cimiciformis outlines a complex evolutionary scenario. On the one hand, the round morph and the ants, engaged in a trophobiotic relationship, should be subjected to the conflicts of interest typical of mutualism, with selection driving each partner to maximize its benefit by giving the least of its own energy and resources. On the other hand, the flat morph and the ants can be expected to be engaged in an arms race, with selection favoring improved deceiving abilities in the aphid and increasingly finer discrimination abilities to detect noncolony members in the ants.
By the way, if you go to the paper’s website, you can see three bonus movies of ant/aphid behavior and interactions that don’t appear in the paper.
Today’s Jesus and Mo strip touches on the continuous battle in the United Nations about passing anti-blasphemy guidelines. This drive is, of course, promulgated almost entirely by Muslim states, while the U.S. and other democracies have always opposed such strictures, peace be unto them. While at one time I was really worried that these “laws” would be approved, it now seems as if they won’t, and the Charlie Hebdo matter will make it even harder.
Reader John Crisp, who lives in Ethiopia, sent photos of an amazing bird that looks as if it were the product of an artist’s twisted imagination. His notes:
Every morning I take our d*g Nala for her morning walk across the meadow by the “creek”, near where we live on the edge of Bahir Dar, Ethiopia. With the rainy season having ended over a month ago, it’s now shallow and brackish. Fish unsold in the fish market float on the surface. There are a couple of cow carcases lying by it, so it smells of decaying meat. But all this free food attracts the birds: maribou storks, common storks, white storks, sacred ibis, hadada ibis, vultures, kites. Yesterday, a special treat: a solitary saddle-billed stork (Ephippiorhynchus senegalensis):
What the hell is this thing? It looks like a bird designed by Picasso!
According to Wikipedia, this bird makes no noise except for clattering its bill, and “is a huge bird that regularly attains a height of 150 cm (59 in), a length of 142 cm (56 in) and a 2.4–2.7 m (7.9–8.9 ft) wingspan”.
Oh, and just to give a bit of atmosphere, beyond the meadow we are in rural Ethiopia, where the ploughing (plowing) is still done with a wooden plow and oxen, the houses are still built with sticks, mud and straw… and the farmers don’t work for 160 days in the year because the priests tell them that they will go to hell if they do.
Reader (and biologist) Jacques Hausser sent more hoverflies (syrphids), flies whose adults eat nectar and pollen, and often are Batesian mimics of wasps or bees—insects in the order Hymenopera (syrphids are in the Diptera). These mimics are pretty amazing, and would fool you if you saw them in the wild. The identifications below are Jacques’s:
Episyrphus balteatus (in english “marmalade hoverfly” !): this one has predatory larvae feeding on aphids:
Volucella pellucens: larvae live in wasps’ nests, where they devour the wasps’ larvae as well as dead adults:
Scaeva selenitica: like Episyrphus, the larvae feed on aphids.
Eristalis arbustorum: the larvae, known as rat-tailed maggots, live in polluted water (even in liquid manure) and are detritivorous. They survive thanks to their long caudal respiratory tube.
Here’s a picture of an Eristalis larva (they’re also called “mousies”) showing the long caudal tube (and a finger for scale); you can read more about them here. They’re often sold in shops as fish bait:
