oh yeah…here’s a video of the bird I wrote about yesterday. COOL!
One heckuva lekker: the magnificent Golden-collared Manakin
I was in the jungle in Bocas del Toro, Panama, last May when I heard this strange noise. Listen for the sound of marbles knocking together.
I saw this bird and miraculously got a good photo:
When I got back, I looked at my bird guide and realized that I’d just seen a Golden-collared Manakin!! Gasp! This is a really cool bird. Along with peacocks and cock-of-the-rocks, it’s a classic example of a lekking bird.
(Side note: here’s a cock-of-the-rock that I saw in Ecuador, and you can hear their raucous calls around 2:10 of this podcast episode.)
Lekking is when the males gather together in groups and do a colorful and/or noisy display, something very exuberant and eye-catching. Picture high school. They’re trying to catch the eyes of the females, but they’re also catching the attention of predators, so it begs the question: How could this behavior evolve if it could easily get you killed?
Turns out that leks aren’t 100% understood yet, but one idea is that they evolve when the dad doesn’t have to help with child care. In manakins, for examples, it’s easy for the mom to find enough fruit to feed her chicks, but birds grow slowly on a fruit diet (it’s low in protein). So it’s easier to hide the nest during a long chick-hood if there’s only one parent always coming and going.
If the only thing that Dad is contributing to the chicks is his genes, and not help with child care, then Mom has to make sure she gets some damn good genes for her babies. All the displaying at a lek is somehow helping her choose her children’s father, maybe by showing her signals of health and strength, or maybe because the males are competing with each other, and it’s the dominant guy who gets the girl.
Anyway, it makes for some spectacular shows. Every species has its own kind of display. The golden-collared manakin dances by jumping from sapling to sapling, and in between he SNAPS his wings—that’s the marble-knocking noise you hear in the audio. The dance is incredibly fast, so the female can see how quick and agile he is.
A few days after I first saw and heard a manakin, I was lucky enough to actually see the dance in action. And I’ll tell you what: if I were a female golden-collared manakin, I’d totally go for that.
Reference: J. Kricher, A Neotropical Companion (Princeton University Press, Princeton, ed. 2, 1997)
![Darwin quote of the month:
“It has been one of the greatest oversights in my work that I did not experimentise on [small and inconspicuous] flowers, owing to the difficulty of fertilising them, and to my not having seen the importance of the subject.”
After doing thousands of crosses of Arabidopsis thaliana (shown above), members of my lab (Schemske lab at MSU) would agree—these are not the easiest flowers on which to experimentise.
Actually, in this quote Darwin is referring specifically to cleistogamous plants, which produce small flowers that self-pollinate and never open (“cleistogamous flowers”), in addition to the more typical open flowers that receive outcross pollen from other individuals (“chasmogamous flowers”). Nearly 700 species have this mating system, and it has independently evolved some 40 times. Families that have some cleistogamous members include the Poaceae (grasses), Violaceae (violas), Fabaceae (legumes), and Orchidaceae (orchids). (Arabisopsis thaliana, to be clear, is not cleistogamous, it just has small flowers. I couldn’t find a good picture that obviously shows cleistogamy.)
Cleistogamous species are fascinating because they allow us to study factors that maintain outcrossing. Cleistogamous flowers are cheap to produce, and any self-pollinated seeds have twice the amount of parental genetic material (both mom’s and dad’s) than outcrossed seeds—so already you can see why they’re a good idea under the laws of natural selection. On the other hand, chasmogamous flowers are expensive to produce compared to the cleistogamous ones, so they have to repay that cost by producing seeds that will somehow be more fit than seeds produced by the cleistogamous flowers, or else eventually the species would evolve to have only cleistogamous flowers. So how are these flowers worth it?
It turns out that perpetual self-pollination is not necessarily a good thing. A selfing lineage will build up genetic load—it can accumulate some non-lethal but no-good mutations (due to genetic drift in this effectively small population). How can this genetic load be relieved? By outcrossing. And that, we think, is why it’s worth it to produce those expensive chasmogamous flowers—for the benefits of sex with another individual.
——————————————————————————————
Photo: Thale Cress (Arabidopsis thaliana) by bbusschots on Flickr.
Darwin quote from: The effects of cross and self-fertilisation in the vegetable kingdom, 1876, p. 387
References:
Cully TM, Klooster MR. 2007. The Cleistogamous Breeding System: A Review of Its Frequency, Evolution, and Ecology in Angiosperms. Bot. Rev. 73(1): 1-30
Oakley CG, Moriuchi KS, Winn AA. 2007. The Maintenance of Outcrossing in Predominantly Selfing Species: Ideas and Evidence from Cleistogamous Species. Annu. Rev. Ecol. Evol. Syst. 38:437-457](http://24.media.tumblr.com/tumblr_lsaesxoRWT1qgrjcao1_500.jpg)
Darwin quote of the month:
“It has been one of the greatest oversights in my work that I did not experimentise on [small and inconspicuous] flowers, owing to the difficulty of fertilising them, and to my not having seen the importance of the subject.”
After doing thousands of crosses of Arabidopsis thaliana (shown above), members of my lab (Schemske lab at MSU) would agree—these are not the easiest flowers on which to experimentise.
Actually, in this quote Darwin is referring specifically to cleistogamous plants, which produce small flowers that self-pollinate and never open (“cleistogamous flowers”), in addition to the more typical open flowers that receive outcross pollen from other individuals (“chasmogamous flowers”). Nearly 700 species have this mating system, and it has independently evolved some 40 times. Families that have some cleistogamous members include the Poaceae (grasses), Violaceae (violas), Fabaceae (legumes), and Orchidaceae (orchids). (Arabisopsis thaliana, to be clear, is not cleistogamous, it just has small flowers. I couldn’t find a good picture that obviously shows cleistogamy.)
Cleistogamous species are fascinating because they allow us to study factors that maintain outcrossing. Cleistogamous flowers are cheap to produce, and any self-pollinated seeds have twice the amount of parental genetic material (both mom’s and dad’s) than outcrossed seeds—so already you can see why they’re a good idea under the laws of natural selection. On the other hand, chasmogamous flowers are expensive to produce compared to the cleistogamous ones, so they have to repay that cost by producing seeds that will somehow be more fit than seeds produced by the cleistogamous flowers, or else eventually the species would evolve to have only cleistogamous flowers. So how are these flowers worth it?
It turns out that perpetual self-pollination is not necessarily a good thing. A selfing lineage will build up genetic load—it can accumulate some non-lethal but no-good mutations (due to genetic drift in this effectively small population). How can this genetic load be relieved? By outcrossing. And that, we think, is why it’s worth it to produce those expensive chasmogamous flowers—for the benefits of sex with another individual.
——————————————————————————————
Photo: Thale Cress (Arabidopsis thaliana) by bbusschots on Flickr.
Darwin quote from: The effects of cross and self-fertilisation in the vegetable kingdom, 1876, p. 387
References:
Cully TM, Klooster MR. 2007. The Cleistogamous Breeding System: A Review of Its Frequency, Evolution, and Ecology in Angiosperms. Bot. Rev. 73(1): 1-30
Oakley CG, Moriuchi KS, Winn AA. 2007. The Maintenance of Outcrossing in Predominantly Selfing Species: Ideas and Evidence from Cleistogamous Species. Annu. Rev. Ecol. Evol. Syst. 38:437-457
The second show I did about insect sex for Rice Radio a year and a half ago…
Insect Sex Part 2: Collembola (Springtails)
Insects are an incredibly diverse group of animals with an equally diverse set of strategies for making babies. This is part two of a short series of shows where we bring you the stories of some of these reproductive strategies. You’ll hear about death and violence, seductive dances, cross-dressing, bizarre gender roles, and more. Technically, springtails are not actually insects, but they are the next closest thing.
We won’t be talking about human sex or making any off-color jokes, but if you think that you or your kids would not want to hear scientific words about sexual organs and acts, then maybe you shouldn’t listen to this show.
aired: April 23, 2010
length: 10 minutes
produced by: Carina Baskett
interviewee: Dr. Jennifer Rudgers
music by:
Reverend Gary Davis / CC BY-NC-SA 3.0
Ergo Phizmiz & Margita Zalite / CC BY-SA 2.0
Ergo Phizmiz / CC BY-NC-SA 2.0
theme music by: Joelle Zigman
click here to go to our archive, where you can download this show.
This post on the Mother Nature Network about insect mating rituals reminded me of my two favorite shows I ever did for Rice Radio. Here’s the first, about the sex lives of ants and bedbugs.
Insect Sex
Insects are an incredibly diverse group of animals with an equally diverse set of strategies for making babies. This is part one of a short series of shows where we bring you the stories of some of these reproductive strategies. You’ll hear about death and violence, seductive dances, cross-dressing, bizarre gender roles, and more.
We won’t be talking about human sex or making any off-color jokes, but if you think that you or your kids would not want to hear scientific words about sexual organs and acts, then maybe you shouldn’t listen to this show.
aired: April 9, 2010
length: 16 minutes
produced by: Carina Baskett
interviewees: Dr. Scott Solomon and Dr. Tom Miller
music by: Lanark and Animals & Men
theme music by: Joelle Zigman
click here to go to our archive, where you can download this show.
download ↓
Centennial Theme by One by Four. Powered by Tumblr.
