|WikiProject Genetics||(Rated Start-class)|
|WikiProject Evolutionary biology||(Rated C-class, High-importance)|
|To-do list for Handicap principle:|
First Paragraph Needs work
The first paragraph needs rewording to make this concept clearer. As it is now, it seems to be a circular reference and is difficult to understand. Ideas are repeated without being clarified any further.
This article should really be titled the Handicap Principle, which I think is what Zahavi originally called it.
Unless one beleives that a 'principle' is something that requires a certain definition be met, and that the Handicap Theory fails to meet it... Pete.Hurd 01:38, 29 August 2005 (UTC)
- No, what one believes is irrelevant, what matters is the name that is normally used for it. In my experience it's always called a "principle", and google confirms: , . I agree it should be moved. David Sneek 21:07, 10 February 2006 (UTC)
- Fair enough, go for it. Pete.Hurd 21:29, 10 February 2006 (UTC)
Not yet ready for GA
I believe this article requires more work before placing up for GA. It is too short, was not wikified, has difficult english almost unintelligible to non-scientists and could do with expansion. The nice graphs placed above by Pete Hurd need to be added in the text if they are relevant. Some reference to the counter examples are hidden in wikitext. Why? NPOV requires both sides of the arguments to be presented. It would also be nice if an image of stotting can be added to give greater graphical appeal to the article. I feel the article has potentioal for GA but after more work. It may fail in its present state. Regards, AshLin 13:24, 5 July 2007 (UTC)
Does this account also apply to the human penis? --Gargletheape 17:12, 24 September 2007 (UTC)
- It's only speculative, but yes, Dawkins suggested so in The Selfish Gene (I think he was the first). The idea is that those that can't maintain an erection are likely to have something or other wrong with them. Richard001 04:44, 8 October 2007 (UTC)
Are interspecific use of 'handicap' signals a form of aposematism? I've had problems with this for some time, and haven't found a clear definition of aposematism given anywhere. Basically there are two forms ways of looking at it - narrow aposematism is warning signals that say 'Don't eat me, I'm harmful', and broader aposematism say 'Don't pursue me, I'm not profitable'. For organisms that can't flee, the second one doesn't apply. But a gazelle stotting is basically the same functionally in terms of fitness as a bright coloured mushroom. The message is "Don't pursue/eat me - it isn't worth it in terms of fitness".
Some aposematic organisms also seem to display handicap principle-esque behaviors, for example the leisurely flying of poisonous butterflies seems to say 'look at how I can flutter around in front of you like this - do you think I would do that if I wasn't poisonous?' I've added it to see also, though I think it should ideally be mentioned in the article for completeness. Richard001 04:59, 8 October 2007 (UTC)
- Hmmm, I would say that an aposematic butterfly leisurely flying along is playing it safe. If it were to zip and zoom, then a predator might quickly snatch at it before adequately processing the signal. A slow moving toxic prey item has nothing to fear, and can move as it wishes, as long as it is recognized for what it is, and that might be facilitated by moving slowly. Pete.Hurd 06:12, 8 October 2007 (UTC)
I've found a paper discussing this - Are Warning Colors Handicaps? Tim Guilford; Marian Stamp Dawkins Evolution > Vol. 47, No. 2 (Apr., 1993), pp. 400-416. Richard001 08:29, 9 October 2007 (UTC)
The lead seems to approach the principle from a signalling theory angle. Historically, I believe the principle was introduced to explain the existence of adaptations that appear by teleological reasoning to be maladaptive. It seems so much more easy for a beginner to grasp the idea that way then to begin with the conditions for signals to evolve. IMHO, using the historical evolution of the subject is often a good way to structure conceptual articles. Shyamal 03:59, 14 November 2007 (UTC)
- I believe that the simplest lead would explain that the principal arose out of a need to explain how cheating must be precluded for evolution to choose the more adapted individual, a point that is not explained by group selection. The principal is first and foremost a reaction to the concept of group selection. —Preceding unsigned comment added by 220.127.116.11 (talk) 11:05, 13 November 2010 (UTC)
Perhaps physical examples in humans should be included. Dimorphism is related to the handicap principle: all other things being equal bigger, taller males are seen as more attractive, men with more prominent, squarer jaw being more physically attractive can be seen as the human equivalent of the peacock tail because it it more biologically costly to develop and perhaps maintain. There are plenty of physical example amongst people. It's not simply limited to behavior. —Preceding unsigned comment added by 18.104.22.168 (talk) 01:13, 5 May 2008 (UTC)
- Problem is that it all looks nice on paper and in theory, but has it been studied whether, all other things being equal, the handicapped males can be expected to have lower fitness (less offspring/shorter lifespan)? For example, "conspicuous consumption" and bungee jumping are not cases of the handicap principle actively at work - the mortality rate of bungee jumping is quite low, and the conspicuous consumer does not spend his food money on trinkets. These examples properly belong in the group of handicapless "show-off" traits, which are extremely common (e.g. gamebird wattles are brigt red and large in healthy males, and small and pale in unhealthy males, and thus signal how much energy males can "waste" by investing into ornaments in a much simpler fashion).
- The article needs more examples in general. The whole thing makes sense as a theoretical consideration, but in how far a sexual signal constitutes a handicap to its bearer must be quantified. For long tails in birds, this is easy; take a few short-tailed males and a few long-tailed ones before the breeding season, and cut off the tail tips of half of the latter and glue them to the tail tips of half of the former. After the breeding season, measure survival. Only if survival of artificial longtails vs natural shorttails and of natural longtails vs artificial shortails is significantly higher, you have the handicap principle at work. Otherwise it is just the usual honest sexual signalling, meaning that individuals which are strong and healthy have surplus energy to invest in ornaments.
- But such comparative studies have been performed, with mixed results I think. Genuinely handicapping signals seem to be rather rare. Peacock trains (not "tails" - the peacock tail is short and serves as a prop-up for the long uppertail coverts) are an example. But OTOH, a "tail"less peacock will have zero mating success, and thus though the principle may have been the driving force in peacock train evolution, the extent to which it applies now is unclear. For Barn Swallows there are loads of studies but support is surprisingly slim: males shift foraging strategies according to tail length, thus the handicap is dependent on prey availability (in habitat with a high amount of mosquitoes and few butterflies, a short tail may actually be the bigger handicap). For the Red-tufted Sunbird, an active handicap principle has been confirmed: males with long tails need more time to forage. Dysmorodrepanis (talk) 12:59, 7 June 2009 (UTC)
- Also, if a strong handicap and strong female choice exists, one would expect the handicap effect to be eventually counterbalanced by evolution of dishonest sexual signalling. "Poseur principle" one might call it - males investing resources they can little afford into ornaments that decrease their fitness even more will be advantageous as soon as the fitness gain by higher attractivity outweighs the fitness loss of the handicap. Dysmorodrepanis (talk) 13:08, 7 June 2009 (UTC)