Login |
New User
Over 1.5 million copies sold
Books by Richard Dawkins
The Oxford Book of Modern Science Writing
by Richard Dawkins
The Selfish Gene
by Richard Dawkins
The Blind Watchmaker
by Richard Dawkins
The Ancestor's Tale
by Richard Dawkins
Unweaving the Rainbow
by Richard Dawkins
Climbing Mount Improbable
by Richard Dawkins
Print
Beetle drive
by The Economist
Thanks to Ivan Bailey for the link.
http://www.economist.com/science/displaystory.cfm?story_id=12001839
Beetle drive
Dung beetles provide an object lesson in the speed of natural selection
ONE of the lies regularly promulgated by creationist ideologues is that you cannot see evolution in action right now. For microorganisms this is obviously untrue. The evolution of new viral diseases, such as AIDS, is one example. The evolution of antibiotic-resistant bacteria is another. But bacteria and viruses breed fast, so natural selection has time, within the span of a human life, to make a difference. For species with longer generations, examples are less numerous. But they do exist.
A new one has just been published, appropriately, in Evolution. It concerns dung beetles. Harald Parzer and Armin Moczek, of Indiana University, have been studying a species called Onthophagus taurus. Or, rather, it was a species 50 years ago, but it is now heading rapidly towards becoming at least four of them.
Onthophagus taurus lives naturally in southern Europe and the Middle East, but it has booted about a bit and is now found in many other places too. Mr Parzer and Dr Moczek looked at beetles from the east and west of Australia (where it was deliberately introduced to deal with the dung of non-native livestock) and North Carolina, together with an aboriginal population from Italy. Their interest was the trade-off that the males of various populations make between what they delicately describe as the beetles' primary and secondary sexual characteristics—in other words, their penises and their horns. The researchers' hypothesis was that the bigger the horns, the smaller the penis, and vice versa.
Male Onthophagus beetles use their horns to fight over females. Lose a fight and you do not get to mate. On the other hand, if you do get to mate, having big sexual organs is likely to increase the chance that it will be your sperm, rather than another male's, that fertilise the female's eggs. Beetles, like butterflies and moths, have a four-stage life cycle of egg, larva, pupa and adult. Mr Parzer and Dr Moczek hypothesised that given the limited resources available to make an adult beetle (in other words, the flesh of the larva that made the pupa), those parts of the adult focused on reproducing will take a constant chunk. Exactly how that chunk is allocated will depend on the local conditions the adult has to face. The more fighting it is likely to have to do, the more its horns will require, and the less will be left over for its penis.
The horns of a dilemma
As they predicted, the two researchers found that the bigger a beetle's horns, the smaller its penis. More importantly, though, the ratio was different in each of the four populations, but similar within each population. That suggests it is being set by local natural selection in each place. Moreover, Mr Parzer and Dr Moczek also looked at ten other species of Onthophagus to see whether the trade-off applied to them too. It did. The ratio of horn to penis size was different in each species, but consistent within a species.
Given the need for male and female organs to fit together, the researchers suggest that selection of horn size might be the main method of speciation in Onthophagus. Horn size determines penis size. Penis size then dictates vagina size. That stops crossbreeding between groups and provides the reproductive isolation that groups need to evolve into species.
As evidence, they point out that the genus Onthophagus has 2,400 species—more than any other in the animal kingdom. And their work suggests it is just about to get three more, in the shape of the east and west Australian, and North Carolinian populations, if, indeed, these groups are not species already. Since it is known when these populations were introduced, and none is more than half a century old, evolution seems to have worked its wonders well within a human lifetime. Darwin, no doubt, would have been delighted.
http://www.economist.com/science/displaystory.cfm?story_id=12001839
Beetle drive
Dung beetles provide an object lesson in the speed of natural selection
ONE of the lies regularly promulgated by creationist ideologues is that you cannot see evolution in action right now. For microorganisms this is obviously untrue. The evolution of new viral diseases, such as AIDS, is one example. The evolution of antibiotic-resistant bacteria is another. But bacteria and viruses breed fast, so natural selection has time, within the span of a human life, to make a difference. For species with longer generations, examples are less numerous. But they do exist.
A new one has just been published, appropriately, in Evolution. It concerns dung beetles. Harald Parzer and Armin Moczek, of Indiana University, have been studying a species called Onthophagus taurus. Or, rather, it was a species 50 years ago, but it is now heading rapidly towards becoming at least four of them.
Onthophagus taurus lives naturally in southern Europe and the Middle East, but it has booted about a bit and is now found in many other places too. Mr Parzer and Dr Moczek looked at beetles from the east and west of Australia (where it was deliberately introduced to deal with the dung of non-native livestock) and North Carolina, together with an aboriginal population from Italy. Their interest was the trade-off that the males of various populations make between what they delicately describe as the beetles' primary and secondary sexual characteristics—in other words, their penises and their horns. The researchers' hypothesis was that the bigger the horns, the smaller the penis, and vice versa.
Male Onthophagus beetles use their horns to fight over females. Lose a fight and you do not get to mate. On the other hand, if you do get to mate, having big sexual organs is likely to increase the chance that it will be your sperm, rather than another male's, that fertilise the female's eggs. Beetles, like butterflies and moths, have a four-stage life cycle of egg, larva, pupa and adult. Mr Parzer and Dr Moczek hypothesised that given the limited resources available to make an adult beetle (in other words, the flesh of the larva that made the pupa), those parts of the adult focused on reproducing will take a constant chunk. Exactly how that chunk is allocated will depend on the local conditions the adult has to face. The more fighting it is likely to have to do, the more its horns will require, and the less will be left over for its penis.
The horns of a dilemma
As they predicted, the two researchers found that the bigger a beetle's horns, the smaller its penis. More importantly, though, the ratio was different in each of the four populations, but similar within each population. That suggests it is being set by local natural selection in each place. Moreover, Mr Parzer and Dr Moczek also looked at ten other species of Onthophagus to see whether the trade-off applied to them too. It did. The ratio of horn to penis size was different in each species, but consistent within a species.
Given the need for male and female organs to fit together, the researchers suggest that selection of horn size might be the main method of speciation in Onthophagus. Horn size determines penis size. Penis size then dictates vagina size. That stops crossbreeding between groups and provides the reproductive isolation that groups need to evolve into species.
As evidence, they point out that the genus Onthophagus has 2,400 species—more than any other in the animal kingdom. And their work suggests it is just about to get three more, in the shape of the east and west Australian, and North Carolinian populations, if, indeed, these groups are not species already. Since it is known when these populations were introduced, and none is more than half a century old, evolution seems to have worked its wonders well within a human lifetime. Darwin, no doubt, would have been delighted.
Add to del.icio.us
Posted: Friday, August 29, 2008 | PermalinkComments 1 - 45 of 45 |
Reload Comments | Back to Top | Page Numbers2. Comment #239137 by Annamation on August 29, 2008 at 6:35 am
Why do men and cars come to mind when reading this? Other Comments by Annamation
3. Comment #239138 by root2squared on August 29, 2008 at 6:41 am
Why do men and cars come to mind when reading this?
True. The bumper sticker on my MINI is
Car Size + x = k
For x = 0, k = H2
Guys who drive SUVs/trucks/H2s please don't flame me. It's a joke!
Other Comments by root2squared
4. Comment #239140 by epeeist on August 29, 2008 at 6:42 am
Comment #239136 by Big GusI can see them putting their fingers in their ears already! Good research though, it at least provides us with a rebuttal to the claim that "If evolution is true why don't we see it happening"Here is a prediction. When you point out this as an example of speciation they will respond with "But it is still a beetle".
Other Comments by epeeist
5. Comment #239141 by bugaboo on August 29, 2008 at 6:43 am
Is this not sexual selection?edit: epeeist
Here is a prediction. When you point out this as an example of speciation they will respond with "But it is still a beetle".
Ah! of course, they havent changed kind.
Other Comments by bugaboo
6. Comment #239143 by stptrck75 on August 29, 2008 at 6:45 am
Horny little bastards. Other Comments by stptrck75
7. Comment #239145 by SamKiddoGordon on August 29, 2008 at 6:50 am
I dont want to be called a racist, but we will soon know, through science, that artificial selection by religious dogma, has caused evolution in humans. For example Islam. Since its inception as a mind virus and meme, has selectivly bred a population to sustain itself dispite its natural environment. In other non-human populations, when this occurs and an imbalance is created and eventually the population implodes and nature restores the imbalance. So, how long can this population sustain itself before it implodes, and when it does what happens next? Other Comments by SamKiddoGordon
8. Comment #239150 by Annamation on August 29, 2008 at 6:56 am
Comment #239145 by SamKiddoGordon
Looking at the mess in the middle east, I'd say the 'implosion' has already begun. As to what happens next? well that will be determined by the lessons learnt or not!
Other Comments by Annamation
9. Comment #239160 by Cobra in the fire on August 29, 2008 at 7:14 am
I would say that is a dangerous comment....You could substitute any zealously dogmatic group e.g white "Evangelical" Americans. For Evangelical read fundamentalist...This suggestion would apply to any particular group...Catholics? Israelis? Protestants?
Be careful how you generalise?
Other Comments by Cobra in the fire
10. Comment #239179 by Hellene on August 29, 2008 at 8:01 am
Edit: sorry bad link. Other Comments by Hellene
11. Comment #239180 by Cartomancer on August 29, 2008 at 8:01 am
Wouldn't the optimal solution be to have great big horns that also function as penises? Or is there some limitation on the insectoid body pattern that would prevent this from ever happening? Other Comments by Cartomancer
12. Comment #239181 by someonefree on August 29, 2008 at 8:02 am
SamKiddoGordon,I wouldn't call your comment racist (there are muslims of all colors including white) but I would call it too generalized as you can't really categorize all muslims in one group other then that they are muslim. Also there are other religions living in the regions muslims live and they are of the same ethnic group but different religion. So your comment is not racist but it is useless, that sounds too harsh, lets say not useful. ;) I also wanted to mention that there is cross breading going on with muslims so that would be another reason I would call your comment irrelevant. It would be relevant if muslims only mated with other muslims.
Edit: Clarified, my original post sounded too harsh.
Other Comments by someonefree
13. Comment #239186 by Hellene on August 29, 2008 at 8:10 am
4. Comment #239140 by epeeistHere is a prediction. When you point out this as an example of speciation they will respond with "But it is still a beetle".
They seem to respond to this kind of "evolution" however:
CLICK HERE
Other Comments by Hellene
14. Comment #239193 by Tezcatlipoca on August 29, 2008 at 8:26 am
Hellene,
are you fishing for JM? He and his mentor Haha Yoyo undoubtably will fall for such baiting, hook, line, and sinker...
Other Comments by Tezcatlipoca
15. Comment #239194 by Blue Monster 65 on August 29, 2008 at 8:26 am
Root - that is the funniest thing I've read in ages!
Shame about the beetle's X, though - when will they learn to drive cars?
Scott
Other Comments by Blue Monster 65
16. Comment #239197 by He'sAVeryNaughtyBoy on August 29, 2008 at 8:29 am
"Wouldn't the optimal solution be to have great big horns that also function as penises? Or is there some limitation on the insectoid body pattern that would prevent this from ever happening?"You mean aside from the very foundations of the principles of evolution? If evolution were guided then you might have a case, but it isn't so that's just the way it works out.
Other Comments by He'sAVeryNaughtyBoy
17. Comment #239201 by Hellene on August 29, 2008 at 8:30 am
14. Comment #239193 by TezcatlipocaWe actually "have three horned" beetles in Florida. I've never seen a live one, but have found dead ones in swimming pools. I'm looking at one on top
of my monitor as we speak. No hook though. ;)
Other Comments by Hellene
18. Comment #239205 by Roger Stanyard on August 29, 2008 at 8:39 am
"ONE of the lies regularly promulgated by creationist ideologues is that you cannot see evolution in action right now."
Watch the wackaroons writing to the Economist - it has a very big circulation in the States. The next edition comes out on Friday.
The basic crap they will put forward is that you might be able to see micro-evolution but not macro-evolution. Of course they carefully forget to tell you that they have a different definition of the two from scientists. None of them will admit it, though, until forced.
Other Comments by Roger Stanyard
19. Comment #239210 by Cartomancer on August 29, 2008 at 8:47 am
You mean aside from the very foundations of the principles of evolution? If evolution were guided then you might have a case, but it isn't so that's just the way it works out.But evolution generally does reach the optimal survival solutions provided those solutions are viable. Those individuals who hit upon the optimal solution will be at an advantage over those who do not have it, it just takes enough time for cumulative mutation to explore the phase space of the problem and find it.
What this means is that, since we do not see beetles with giant penis-horns anywhere in nature (and many other animals have developed similar appendages into sperm-delivery systems, like octopus and squid) there is probably some developmental factor preventing them from reaching this solution. Either that or it's not really the optimal solution it seems to be. Maybe using your reproductive organs as weapons exposes them to unnecessary dangers? Or maybe there really isn't any gradual path of tiny steps that could move the penis to the head area, each providing an incrementally more advantageous configuration than the last?
Other Comments by Cartomancer
20. Comment #239211 by John Locke on August 29, 2008 at 8:50 am
root
dude...have to be honest jokes using equations are a touch sad...not a bad one though!
Other Comments by John Locke
21. Comment #239214 by Hellene on August 29, 2008 at 8:53 am
18. Comment #239205 by Roger Stanyard"The basic crap they will put forward is that you might be able to see micro-evolution but not macro-evolution. Of course they carefully forget to tell you that they have a different definition of the two from scientists. None of them will admit it, though, until forced. "
Exactly how is their definition different?
I have reason for asking. :)
Other Comments by Hellene
22. Comment #239217 by squinky on August 29, 2008 at 8:55 am
Carto,
That would certainly lend new meaning to the term 'cockfight'.
I'm a little skeptical of the conclusions drawn in this research (admittedly I didn't read the paper). In ducks it's been shown that male penis size and length has been driven by female vaginal evolution. The females cannot prevent being mated with (duck raped essentially) but they've evolved a way to only allow the desired male's sperm to fertilize her. Male ducks are rapidly evolving different penis combos to counter the females' 'cockblocker'.
Other Comments by squinky
23. Comment #239220 by Ilesere on August 29, 2008 at 9:03 am
This raised an odd thought - the rates of infertility seem (by that I mean I've heard through various media without any scientific analysis, so it's mainly anecdotal) to be increasing. Is there any evidence for any level of speciation within human populations as a result of long periods of segregation, and is any of the allegedly increasing infertility actually a manifestation of that? For lack of better examples do differences in the population of central asians and south american indians (populations I reckon to be fairly well segregated for the past few thousand years) mean they would now be unable to breed?Other Comments by Ilesere
24. Comment #239247 by flobear on August 29, 2008 at 10:05 am
Carto: But evolution generally does reach the optimal survival solutions provided those solutions are viable.
Well, evolution will gradually approach a local maxima (optima?), but I believe it's inaccurate to say "optimal." Unless there is a gradual pathway of steady improvement towards having the horns be penises as well, I'm afraid the beetle will be stuck in its current configuration. Dawkins' "Climbing Mt Improbable" covers this wonderfully.
cobra: You could substitute any zealously dogmatic group ... Catholics? Israelis? Protestants?
I think you mean "orthodox Jews", not Israelis. Israelis can't really be called a "zealously dogmatic group." Also, they're quite secular - especially compared to the US.
Other Comments by flobear
25. Comment #239265 by He'sAVeryNaughtyBoy on August 29, 2008 at 10:32 am
"Or maybe there really isn't any gradual path of tiny steps that could move the penis to the head area, each providing an incrementally more advantageous configuration than the last?"I think that about nails it. It's like asking why tortoises haven't evolved to fly after years of being dashed upon the rocks - the optimal survival solution for tortoises would be to fly, and we're still waiting to see the worlds first flying tortoise.
Other Comments by He'sAVeryNaughtyBoy
26. Comment #239267 by Sciros on August 29, 2008 at 10:39 am
Israelis can't really be called a "zealously dogmatic group." Also, they're quite secular - especially compared to the US.Quite right. Also, a lot of them are Russian immigrants who are basically all atheist.
Anyway this article is awesome, I have been waiting a while for some good solid research on beetle penises. This also is consistent with the myth that bodybuilders have extremely small packages, which makes that myth true!!
Other Comments by Sciros
27. Comment #239274 by Sciros on August 29, 2008 at 10:56 am
dude...have to be honest jokes using equations are a touch sad...not a bad one though!
Equations are only awesome when they arrive at an insightful and useful truth, such as here:
NINJA THEORY which I developed in 2001 -- it is supremely useful to keep in mind when doing battle against ninja. If not for ninja theory's correctness, I would not have been able to take out 17 ninjas the other day armed with nothing but an empty Scotch tape dispenser and the cap from one of those Pilot V7 pens.
Other Comments by Sciros
28. Comment #239277 by root2squared on August 29, 2008 at 11:06 am
dude...have to be honest jokes using equations are a touch sad...not a bad one though!
Hmm...maybe in an anti-intellectual culture where jocks are glorified and intelligence is looked down upon as elitist...yes it would be perceived as such.
Other Comments by root2squared
29. Comment #239280 by root2squared on August 29, 2008 at 11:10 am
Scott
Shame about the beetle's X, though - when will they learn to drive cars?
I guess when the've evolved sufficiently to invent the cellphone and coffee. Otherwise what are they going to do while driving?
Also I see a lawsuit coming Volkswagen's way if they do.
Other Comments by root2squared
30. Comment #239326 by 8teist on August 29, 2008 at 1:12 pm
Thats it, I`m swapping my tuba for a whistle Other Comments by 8teist
31. Comment #239369 by SASnSA on August 29, 2008 at 1:55 pm
CartoEither that or it's not really the optimal solution it seems to be. Maybe using your reproductive organs as weapons exposes them to unnecessary dangers?
I'll go with that one. I know I don't want mine anywhere near any clashing horns. But seriously I've noticed a pronounced trend in evolution towards protecting the genitalia. Without that, the species ain't going nowhere.
Other Comments by SASnSA
32. Comment #239422 by Steven Mading on August 29, 2008 at 2:35 pm
What this means is that, since we do not see beetles with giant penis-horns anywhere in nature (and many other animals have developed similar appendages into sperm-delivery systems, like octopus and squid)
Reminds me of the famous typesetting error in the Green Bay Press-Gazette that described then-governor Tommy Thompson's use of the veto pen with this, unfortunate headline:
THOMPSON'S PEN IS A SWORD
Other Comments by Steven Mading
33. Comment #239435 by ivellios on August 29, 2008 at 2:59 pm
Yes, That's The Folly Of Using Spell Checker And Not Actually Proof Reading Your Material. Other Comments by ivellios
34. Comment #239440 by Border Collie on August 29, 2008 at 3:07 pm
I was going to say something about Chinese and rhino horn but I decided to pass ... I'm sure somebody would be offended.Other Comments by Border Collie
35. Comment #239446 by WilliamP on August 29, 2008 at 3:28 pm
ONE of the lies regularly promulgated by creationist ideologues is that you cannot see evolution in action right now.
Why would a creationsist not believe in something simply becuase it can't be seen?
Other Comments by WilliamP
36. Comment #239452 by SASnSA on August 29, 2008 at 3:53 pm
Why would a creationsist not believe in something simply becuase it can't be seen?
They want to lower it into the same realm of belief as their own religion so that they can fight it as just another belief system saying "Your religion conflicts with mine, so I don't believe in it"
Other Comments by SASnSA
37. Comment #239466 by J Mac on August 29, 2008 at 5:02 pm
You know what they say about a beetle with a big horn.... oh, no, they don't say that.Bugaboo,
"Is this not sexual selection?"
Technically no. The females are not choosing the male with the biggest horn... or biggest "horn". Rather each one helps the male compete with other males.
Other Comments by J Mac
38. Comment #239502 by pyjamaslug on August 29, 2008 at 6:44 pm
Onthophagus taurus?bullshit beetle?
just wondering......;->
Other Comments by pyjamaslug
39. Comment #239727 by Nova on August 30, 2008 at 9:05 am
12. Comment #239181 by someonefreeYour making the assumption that generalizations are always bad. The vast majority of people in many large areas of the middle east all believe basically the same thing and act in basically the same way, it doesn't matter if theres the occasional odd one out, the average will win and thus SamKiddoGordon's comment is still valid.
Other Comments by Nova
40. Comment #240750 by Telic on September 1, 2008 at 2:20 am
11. Comment #239180 by Cartomancer on August 29, 2008 at 8:01 am
Wouldn't the optimal solution be to have great big horns that also function as penises? Or is there some limitation on the insectoid body pattern that would prevent this from ever happening?
Now just because you'd jump at the chance for this kind of a 'ding-dong', doesn't mean that beetles should start doing it.
I suspect if they all started duelling with their penises, they might dispense with the females altogether and go extinct.
Although from a human perspective, I reckon if someone was trying to pick a fight with you, and you pulled out your todger and waved it at them, they might have second thoughts.
I suspect it has more to do with battle being conducted head on in order to push other beetles away from resources, etc.
And given that they've evolved from a simpler body plan where the penis is not on the head, then I suspect it would be many generations before they would start voting republican.
Other Comments by Telic
41. Comment #242493 by latsot on September 3, 2008 at 11:09 pm
Cartomancer:Or maybe there really isn't any gradual path of tiny steps that could move the penis to the head area, each providing an incrementally more advantageous configuration than the last?
That would be my vote. They already have penises and horns that are good at their jobs. It is difficult to think of a path of continuous improvement that would take the beetles from here to your suggestion. Especially since it might also require some corresponding changes in the females to adjust to the new mechanics of mating. Like the old joke: someone asks a local for directions to somewhere and he says "well, I wouldn't start from here."
Plus, I'm not sure that penis-horns would be a (locally) optimal solution anyway, partly because (as you point out) the possibility of damage, but also because it might be important that penises and horns have different properties, or that one or both also serve some additional purpose.
And also, there may be developmental reasons, so despite my starting by saying I favoured one of your candidate reasons, I've finished by advocating them all :)
Other Comments by latsot
42. Comment #242498 by secondsoprano on September 3, 2008 at 11:42 pm
@ root2squared: what is an H2? (We speak a different language down here...)Other Comments by secondsoprano
43. Comment #242500 by 8teist on September 4, 2008 at 12:08 am
secondsoprano, I think thats a Hummer Other Comments by 8teist
44. Comment #242504 by Laurie Fraser on September 4, 2008 at 12:58 am
Hey 8, how goes it? Other Comments by Laurie Fraser
45. Comment #244886 by secondsoprano on September 9, 2008 at 4:25 pm
Ohhh! Thank you. Yes, we have them here (mostly as novelties - wedding cars & the like). Never heard them called that though.Other Comments by secondsoprano
Comment Entry: Please Login
Register a new account
Upcoming Events:
Mailing List
Enter your email:
DVDs
'The Enemies of Reason: The Uncut Interviews' DVD
'Voices of Reason' DVD
'Richard Dawkins: Appearances & Events 2007-2008' DVD
'Enemies of Reason' DVD
'Root of All Evil?' DVD
'Root of All Evil? The Uncut Interviews' DVD
'Growing Up in the Universe' DVD
'Voices of Science' DVD
'The Four Horsemen' DVD
'Break the Science Barrier' DVD
1. Comment #239136 by Big Gus on August 29, 2008 at 6:34 am
Other Comments by Big Gus