A way cool movie on the BBC website, highlights a new finding that these neotropical birds display in pairs, and are presumably unrelated, ruling out kin selection (they don’t talk about this in the article). How this evolved, if it’s not due to kin selection, is unclear, but the authors hypothesize that while the alpha male gets the female, the beta male eventually inherits the mating site. I don’t get it unless the alpha male is always older, or later finds another site, which doesn’t make sense. But anyway, the movie is great . . .
Note, a direct link, with better resolution, is here.
What a cool dance!
Do you know if research on this dance and pair behavior has been published? I’d be interested in knowing a bit more about how in-depth he has studied the mating behavior of these birds.
In particular, I thought it was interesting that in the article the researcher claims:
“The male birds’ partnership lasts up to five years. During that time, the beta male does not copulate.
“He has to wait until alpha male dies – he doesn’t kick him out. So he may be waiting until he’s 10, 15 or even older.”
I find this incredibly hard to believe, especially if the two males are not related, although I know absolutely nothing about Manakin behavior. Do you know if any work has been done involving genetics of the offspring?
I know that many birds that once appeared to be monogamous are now known to participate in sneaked or extra-pair copulations. Now I’m just throwing out ideas, but if resources were scare and territories are limited, wouldn’t it make sense for 2 males to share a territory, as then they could better defend it from intruding males? Then perhaps the males have different mating strategies, with one appearing to get all the copulations while the other employs some other strategy to sneak copulations?
Anyways, I recently found your blog and have very much enjoyed it so far. I’ve not had time to read WEIT yet, but it’s near the top of my list of things to read.
~Mary
(a UofC (and BIOS 21085) alumni)
First of all, great blog!
This is not actually the first known case of male-male mating co-operation. Sinervo and others found in 2006 that “In side-blotched lizards, genetically similar but unrelated blue male morphs settle on adjacent territories and cooperate.” (link)
Could this be a possible alternative explanation to the manakin partnerships, too? Although it’s going to be hard to tell in the absence of such obvious morphological cues as in the lizards.
I’ve just been reading the chapter in The Selfish Gene about harems and beta male submissions to alphas, and this behavior seems to make a lot of sense. Mary’s comment about cooperative defense of the territory is probably a part of it, but consider that untimely deaths are expected in the wild, usually due to predation or disease. The beta is biding his time in hopes that the alpha will kick it, and his assistance in the displays establishes his place to the females.
I don’t know about the manakins’ husbandry, but if the males take a role in rearing the young, this could be further advantageous to the alpha in the case that he dies early the beta could be adoptive to the existing offspring. A bit of insurance, if you will.
If the beta-become-alpha gets a beta of his own, and the same arrangement holds true, it seems that it would be an evolutionarily stable system. Genes that make the betas adopt the alphas’ young would get passed along by beta-become-alphas, and these are likely to be on the same chromosomes that make the alphas pair p with their betas.
It’s just a speculation, but I’m finding apparent altruism like this a lot easier to find possible explanations for.
PS: That courtship dance is beautiful. If I were a miss manakin, I’d be impressed. 🙂
I just had another possibility come to mind, but rereading the article, it seems to be ruled out as they indicate that the males are unrelated.
If the male pairs were brothers, the explanation would be a lot easier, of course. The brothers would pair up and while one of them would get all the ladies, passing on 1/2 of his genes to each of his offspring, the brother while never copulating would still pass on 1/4 of his genes on average since he statistically shares 1/2 his genes with his brother.
I wouldn’t be surprised if such sibling partnerships exist somewhere in nature, even if it’s not the correct explanation for the manakins’.
mandydax:
Genes that make the betas adopt the alphas’ young would get passed along by beta-become-alphas, and these are likely to be on the same chromosomes that make the alphas pair p with their betas.
Did you take a look at the paper I linked to above? Their hypothesis is very similar to yours, but rather than having different genes for alphas and betas, they could both share genetic elements that they somehow self-recognise, a type of ‘greenbeard altruism’.
I wouldn’t be surprised if such sibling partnerships exist somewhere in nature
Cheetah brothers share territories, although they both mate with the females.
windy,
I somehow missed that link the first time through. Thanks for that. The greenbeard hypothesis does make the unrelated males pairing like that make much more sense from the point of view of the betas’ genes, and reinforces the alphas’ as well. Fantastic!