If you’ve just arrived here on account of my contribution to the Scientific American guest blog, welcome! I hope you’ll have a look through the archives, and consider adding me to your regular online reading. Allow me to suggest a few posts that should give you an idea about what’s going on here:
I’ve contributed another post to the Scientific American guest blog, this time on a topic appropriate for Pride month: how natural selection might (or might not) act on same-sex orientation in humans. Be advised that there is some math.
There’s just a week left to send in your posts for the Pride edition of the Diversity in Science Blog Carnival. The carnival will be right here at Denim and Tweed on 30 June, so I need submissions by the 27th so as to have time to put it all together.
Let me add a point I don’t think I’ve made before: blog carnivals are traditionally about aggregating links to blog posts, but you don’t have to write a thousand-word essay to contribute. You can send in photos, videos, even favorite songs—or send links to other folks’ work (credited appropriately!) that you think the DiS audience would appreciate. Carnivals celebrate by aggregating, and we’re interested in all kinds of media.
Say it ain’t so, Stephen Jay. To demonstrate that a historic (and racist) study of human skull size was biased by systematic manipulation of data, Stephen Jay Gould systematically manipulated data.
Save a serviceberry bush—eat venison! A multi-decade experiment provides strong evidence that too many deer are bad for forests.
Not by running with scissors. How the cave-dwelling isopod lost its eyes
No new science post this week, because I’m taking my time to put together a (hopefully) particularly good, detailed article for the near future. In the meantime, let me suggest something from the D&T archives for Pride month, in advance of the Diversity in Science carnival in a couple weeks. Specifically, my review of Joan Roughgarden’s survey of sexuality across the animal kingdom, Evolution’s Rainbow:
This interest in the evolutionary context of diversity would eventually become much more personal. In 1998, [Roughgarden] came out as transgendered, taking the name Joan after decades spent establishing her scientific reputation under the name she was given at birth, Jonathan. In addition to the challenges inherent to gender transition, Roughgarden’s expertise intersects with her identity in one awkward question: in a biological world shaped by natural selection, how can we explain the evolution of lesbians, gay men, and transgendered people—individuals who are not interested in sexual activity that passes on their genes?
Roughgarden’s answer was to begin a program of research questioning the dominant way of thinking about sex in an evolutionary context. In 2004, she presented her conclusions comprehensively in the book Evolution’s Rainbow, calling for biologists to re-think they way they understood and described sexual behavior throughout the animal kingdom. As another biologist with an admitted personal interest in the question, I’ve found Evolution’s Rainbow to be a great starting point for thinking about sexuality in an evolutionary context.
For in-depth looks at three examples of “alternative” animal lifestyles and the reception Roughgarden’s ideas met in the broader evolutionary biology community, go read the whole post.
There’s a reason you have to make small talk with your barber. Photo by Dave Fayram.
If you’re gay, lesbian, bi, trans, or straight and supportive, and you have an even slightly science-related blog, why haven’t you submitted a post for the Diversity in Science Carnival? Go, do it now—you can read these great science articles afterward.
Cecropia obtusifolia provides food for ants that come and protect it—unless caterpillars get there first. Photo by wallygroom.
Imagine you need a team of security guards. To find them, you decide not to place an ad in the local paper or on Craigslist. Instead, you build an apartment complex next to your home, complete with a full-service cafeteria providing free hot meals 24 hours a day. You leave the front doors unlocked, then hope that anyone who shows up to live in the apartments will also keep an eye on your home.
If you took that strategy to protect your assets, you’d have to be crazy. But that’s pretty much what ant-protected plants do all the time. They grow hollow structures called domatia, secrete nectar from special structures, and even produce tasty and nutritious “food bodies.” Then they wait for ants to move into the domatia, eat the nectar and the food bodies, and hopefully chase away anything that might want to do the plant harm. The crazy thing is, it works.
Well, it mostly works.
One gap in the ant-protection mutualism is the period when an ant-protected plant hasn’t grown big enough to support a whole colony of ants. In this early stage, ants won’t colonize the plant, but other insects might be quite happy to take the rewards that are already being offered. That’s exactly what larvae of the butterfly Pseudocabima guianalis do—they make themselves at home on unprotected ant-plants.
The ant-plant Pseudocabima caterpillars target is Cecropia obtusifolia, a shrubby Central American tree that relies on ants in the genus Azteca for protection. Azteca ants make vicious and well-coordinated bodyguards. Here’s video Ed Yong posted last year, showing a bunch of the ants flushing a hapless moth into an ambush.
However, Cecropia saplings can’t produce enough food to support a colony of ants until the plants grow to more than a meter tall. What’s too little for thousands of ants is a feast for a Pseudocabima caterpillar, however. Each caterpillar builds a silk shelter around a region of the plant that grows food bodies, and settles in to eat. As it grow larger, the caterpillar moves into a domatium near its original shelter, covering the entrance hole with silk. Finally the caterpillar pupates inside the domatium, emerging as an adult to lay eggs on another unprotected Cecropia plant.
Eventually the Cecropia saplings grow large enough to attract ants, who run off the caterpillars. However, as the paper I linked to above describes, the caterpillars seem to be able to resist an ant colony’s establishment on the plant—the silk shelters prevent ants from getting to the best sources of food. Cecropia saplings occupied by caterpillars didn’t seem to suffer more herbivore damage than ant-protected plants, but they did grow more slowly over the course of several years’ observations. Caterpillar-infested Cecropia plants were also more vulnerable to infection by a fungus, which the ants removed quite effectively.
Interestingly, though, caterpillar-infested plants also produced less food than those guarded by ants. This is a point of circumstantial evidence for a new model of mutualism I wrote about earlier this year, in which cheating is reduced or prevented when a host like Cecropiabetter mutualists help create better rewards. An ant-protected plant can divert more resources to feeding its tenants, so their work rewards itself. However, Pseudocabima caterpillars are glad to take the lower level of rewards that Cecropia plants offer up to all comers.
In other words, if you’re going to give out free lunches, you can’t really expect everyone who eats to pay you back.
Reference
Roux, O., Céréghino, R., Solano, P.J., & Dejean, A. (2011). Caterpillars and fungal pathogens: Two co-occurring parasites of an ant-plant mutualism. PLoS ONE, 6 : 10.1371/journal.pone.0020538
Picturesque, but maybe not practical. Photo by jimw.
Arsenic Life II: The Response-ening. Rosie Redfield responds to responses to her criticism of the “arsenic life” study, and considers how she’d go about testing the original claims; Carl Zimmer discusses how online criticisms like Redfield’s may have changed the way we review scientific results. And the original paper appears in print (alongside critical responses) for the first time this week.
It’s a simple question of weight ratios. A transportation engineer explains why airships will probably never be widely used.
The bright side is you get to write another review, right? The trouble with writing about the ethics of an emerging technology is that the state of the art changes very quickly.
Life’s building blocks aren’t usually re-used to make models of the starship Enterprise. Biological systems’ use of a relatively small set of widely-available building blocks means that life is like LEGO.
Light and dark examples of Holbrookia maculata. Photo courtesy Simone Des Roches.
So, remember my posts back in February about three lizards that evolved lighter coloration after colonizing the white gypsum sand of White Sands, New Mexico, and about Erica Bree Rosenblum, the University of Idaho biologist who has studied them for most of her career? Sure you do. Well, Rosenblum’s grad student (and my former office-mate and continuing friend) Simone Des Roches has started a blog about her work at White Sands this spring and summer. Go check it out for the latest on Holbrookia maculata, and for Simone’s fantastic photography of the beautiful desert landscape and its inhabitants.
Happy Pride Month! There’s just 26 days left to send in your posts for a special Pride edition of the Diversity in Science Blog Carnival to be hosted right here at Denim and Tweed at the end of the month.
Alberto Roca of Minority Postdoc and I are looking for blog posts and other online writing about the science of human sexual diversity, the experiences of sexual minorities in the sciences, and everything in between. Write something brand new, or submit a classic post. Tell us how science, engineering, or technology helped it get better for you—or tell us how they didn’t help at all.
You can submit posts directly to me by e-mailing a link, or use the handy online form Alberto has set up. Please send submissions by Monday, 27 June so I have time to put everything together for the 30th.
Thanks to all the folks who have contributed so far—it’s shaping up to be a great carnival.
