The residue of design

As a scientist, you know you’ve made it when Boing Boing covers your stuff. I recently collaborated with a team of scientists (Steve Yanoviak, Robert Dudley, and George Poinar) on a manuscript coming out in The American Naturalist. It’s about a nematode whose life cycle has it spending time in the guts of birds and ants, and that has a pretty unique way of doing it. Here’s the, um, straight poop.

Worker ants of the species Cephalotes atratus, like many ants of the treetops, have a hankering for bird poop (lots of nitrogen and salts in a piece of bird poop). Some bird poop, however, is infected with the eggs of our nematode parasite. Now most adult worker ants can’t take solid food; they feed it, instead to their brood back in the nest. However, when infected poop is fed to the brood of Cephalotes atratus ants by their older sisters, the nematodes cause the brood to grow up with bright red (dare we say, berry-like?) gasters. In the paper we build a plausible hypothesis that birds mistake the red gasters (now full of nematode eggs) for fruit, harvest them, pass them as feces, the feces are harvested by Cephalotes workers who bring them back to the nest, and the cycle continues (one key bit of evidence–it’s easy to pluck off an infected gaster and much, much harder to remove the gaster of a healthy ant).

There is no evidence this is a voluntary arrangement–we see no advantage to the ants of harboring these nematodes. Rather, this seems to be another case of a parasite, once inside its host and with its hands on the wiring and machinery, tweaking the host to do its bidding (my endocrinologically inclined pal points out that the nematodes and ants share a host of neurochemicals, so replace “hands” above with “hormones”). The nematodes even make infected ants raise their gasters vertically, making the egg-filled butt-berries infinitely pluckable.

Long before there were neurobiologists, apparently, there were parasites paving the way.

Below the fold, the real story of how this sordid story of manipulation came about.

10 things I like about ants

Image from Alex Wild’s amazing Myrmecos.net

From the home office in Wahoo Nebraska, here are 10 amazing ant facts.

10. If you weighed all the ants in a tropical forest, then weighed all the mammals, birds, reptiles and amphibians, the ants would weigh four time as much.

9. Fire ants are attracted to electricity. No one knows why.

8. The tiniest mature ant colony has 5 workers; the largest has over 100 million.

7. Most ant species have broad diets, but many are incredibly specialized–one eats only spider eggs.

6. Ants invented agriculture–growing fungi on leaves they harvest and mulch–long before humans did.

5. Ants are so successful and common that many ant species specialize on eating other ants.

4. The queens of some ant colonies can live over 10 years, making them some of the longest lived insects.

3. All the worker ants you see are females; all the worker ants from a single colony are most likely sisters.

2. You can recognize the few ant males in a colony by their pinheads and large googley eyes.

1. No ant has been elected to higher office in the United States. Yet.

Visual explanations: what lies ahead

I first saw this video by Michael Welsch a couple of weeks ago and was impressed but didn’t think it particularly blogworthy. Then Seth Godin placed it in the proper context.

Publish or perish indeed. Now that the publishing part is free and without friction, and now that a professor can boil down complex topics to vivid videos, why aren’t tens of thousands of professors scrambling to do this?

Welsch’s video has gone totally viral…how many more folks now grok Web 2.0 because of it? Isn’t that one of your jobs as an academic?

You likely have the technology on your computer right now that would allow you to tell a compelling story about your research and at the same time expand and hone your personal brand. If you had to do such a video as a class assignment, what would be the topic?

Always the trendsetter among myrmecologists in the use of new media, here’s a short video by the artiste, Jack Longino (let it load in the background).

The latest Tangled Bank is up

Check out this week’s compendium of the best blogging in science and medicine, hosted by the always cheeky ouroboros.

The tangled bank, of course, is a reference to EEB’s own Chucky D, perfectly capturing his experiences in the tropical forest:

  “It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life and from use and disuse: a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms.”

How to be creative–variations on a theme

All scientists value creativity: the ability to generate a long list of ideas combined with the ability recognize the best of those ideas. The list grows in proportion to the amount you  read broadly and keep yourselves open to a diversity of experience (something it is hard to justify at times, when it seems its all you can do to master the discipline you are really passionate about). But what about the culling part?  How do you sort through all this experience to  find a new and profitable connection?

Variations on a theme is one creativity technique as old as the diversity of life. Its simple: find something that works and apply it in a different context.

My favorite example of VOT in EEB is optimal foraging theory–a set of models that predict which habitats, prey, and parts of a prey that a predator should eat. Robert MacArthur and Eric Pianka could have invented this theory from scratch, but instead they knew that similar work had been done by economists (ecology/economics … same root) and they borrowed it, changed the names of the variables, and voila a citation classic that raised helped invent Behavioral Ecology. Likewise, Eric Charnov saw something from Microeconomics 101 that asked how the value of an activity declined with the time you put into it– Marginal Value –and applied it to the question of how long a forager stays in a patch that is taught in every Intro Ecology course.

Variations on a theme–same tune, different lyrics–serving the arts and sciences since 954 B.C.

Illustration from BMClocks’s excellent Natural History Artworks

Brown Food Web Friday–in praise of litter ants

 

How’re y’all doing this fine Friday? I’m slogging through a cold once thought vanquished. Now seems intent on hanging over me like a stale chain mail party dress. Bleah.

    In today’s BFWF we contemplate one of the great biological systems on earth–the litter ant nest. Litter ants live on the forest floor in small hollow twigs, empty acorns, or even between leaves. The whole colony may consist of only 100 or so ants, just enough to cover the tip of your pinky. This small size allows litter ants to be incredibly abundant: in a tropical rainforest there may be 5-10 species living together in a meter square plot. Yes, I will admit it, litter ants changed my life.

Every scientist has the occasional “aha!” moment. Mine came sitting on my butt on the forest floor at La Selva, cracking twigs with Margaret Byrne, a graduate student at the University of Florida at the time. I was in the middle of a PhD project happily placing bits of seed and bird poop across the forest floor to see what ants arrived, who consumed what, and if they preferred some bits of habitat and climate more than others. I only saw the ants when they emerged from the leaf litter to crawl on my baits, but that was fine. I was getting my data, and every night at the microscope I would empty my vials and see the biodiversity.

Margaret was collecting litter ant colonies for her research and she offered to show me how. Turns out, it wasn’t hard.

Brown Food Web Friday–great green globs

September found me on Barro Colorado Island, Panama, tromping daily down the Fairchild trail to harvest some experiments. BCI is in the middle of Lake Gatun, a forested valley flooded during the creation of the Panama canal. BCI is thus a former hilltop, isolated by water.

Now, trails at BCI are of two kinds–those that follow ridge tops and catch what little breeze exists 30 m below a forested canopy (good), and those that cut across the topography, allowing you to get a good sense of how hilly this place once was (not so good). The best one can say about the cross country trails is that they clean out your pores and are every bit as effective as a rubber suit in sheddng a few pounds of unwanted water (see left).

Fairchild is a cross-country trail . Also it was the rainy season, meaning that the trails were actually little gushing rivulets. Also, many of you have already discerned that Barro Colorado means “red clay”: very slippery, clingy, red clay. Finally, there are the black palms that strew their 4 meter long fronds–covered with 5 cm needle sharp spikes– on this muddy, nightmarish, stairmaster trail from hell.

About halfway up one of the most wretched stretches on Fairchild was a newly fallen palm trunk suspended half a meter off the ground. It required a bit of finesse, as it was surrounded by aforementioned needle sharp spikes and required one to balance on one leg on a 45 degree pitch while swinging a mud-clogged boot to the other side. Needless to say, I really looked forward to this log every morning.

Over the course of the week, however, I noticed it began to, well, ooze. And drip. Slowly. Somehow, it just seemed to add to the ambience and became a signature memory of this field trip.

Turns out these kind of jelly-like secretions are not all that uncommon in tropical forests where the brown food web is as busy taking wood, leaves, and tapirs apart as the trees and tapirs are at putting themselves together. I sent the latter two photos (not the first one) to Betsy Arnold, a tropical mycologist at the University of Arizona, who replied:

Photo is very cool. From here, looks like a canker-causing pathogen in the early stages of attack. Those pathogens are likely fungal (most likely Asco or Basid) or fungus-like (could be Phytophthora). Early symptoms, as for sudden oak death disease in CA, can include bleeding wounds.

From this we can tentatively conclude that said palm may have fallen in part because it was being dismantled from the inside by a beastie from one of two kingdoms whose niches are approximately the same: Kill palms and convert their biomass into new Ascomycetes, Basidiomycetes, and/or Phytophthora spores. The fact that they do it in such a colorful way is just gravy on the biscuit.

 

Post script:
In the process of adding linky goodness, Google suggested this one:

Ever the empiricist, I googled “ax murderer”.
And no, eBay ain’t trafficking in them. Yet.

When creationists and evolutionary biologists work together

One key to changing minds is first finding common ground.

“We dare to imagine a world in which science and religion cooperate, minimizing our differences about how Creation got started to work together to reverse its degradation,” Rev. Richard Cizik, vice president for governmental affairs of the National Association of Evangelicals, said at the announcement in Washington, D.C.

On heroes in Academia

Two common topics on the blog, the information explosion and setting goals as a young scientist, come together in the discussion of heros. Although the term may sound antiquated, much of science is about finding apt metaphors and making connections. I think having a set of folks whose character and accomplishments are models can be immensely helpful when setting your own life goals.

That said, identifying and emulating heros is a tricky business. Imagine finding a role model 1000 years ago. He or she likely lived in your neighborhood and was thus a sample of perhaps 500 people. Nowadays we live on a planet of 6,000,000,000+ people, virtually all connected by a complex social/electronic web. This guarantees two things: 1) The truly exceptional people will be a lot farther out on the distribution of traits than they were when the planet held only millions, and 2) We find them and celebrate them. As a consequence, the notion of emulating these folks is a sure recipe for neurosis: there are only so many Nobel’s and Pulitizers to hand out. However, that doesn’t mean we can’t use these folks to help set our own course.

One such role model whose interests are amply reflected in this blog is E. O. Wilson, for which Amanda Leigh Haag has a nice profile in SEED magazine. Wilson’s life work reflects a number of themese that any young scientist could profitably contemplate.

1) A feeling for the organism. Wilson knows his ants, and has used this knowledge to make groundbreaking contributions in fields as diverse as physiology, behavior, biodiversity, and systematics. His essay Systematics Ascending from In Search of Nature highlights this philosophy of integrated biology starting with an intimate knowledge of a taxon.

2) Reading and thinking broadly. In a similar vein, poking your nose over the fence to consider other disciplines and philosophies makes you a better thinker. Consilience is Wilson’s vision of the ultimate rapprochement between science and the humanities. Written from the viewpoint of a hardcore scientific rationalist, such a synthesis would never come from someone whose nose rarely left the journal Insectes Sociaux.

3) The role of scientist as teacher. We have discussed earlier the difficulty of changing minds, the need for multiple approaches in doing so, and the vital role the scientific community must play in some of the titanic struggles that lie ahead. Wilson’s most recent book The Creation is written as an open and frank discussion with a Southern Baptist pastor on the glories of the earth’s biodiversity and the need to conserve it. When much of the back and forth on the web is about denigrating other viewpoints, Wilson uses his own background to search for common ground.

4) Choose your collaborators wisely. Find folks whose skills complement your own. Here is one of my underlined quotes from Naturalist, one of the great autobiographies of the past few decades:

I am a poor mathematician. At Harvard as a tenured professor in my early thirties I sat through two years of formal courses in mathematics to remedy my deficiency, but with little progress…I have no taste for the subject. I have succeeded to some extent in theoretical model building by collaborating with mathematical theoreticians of the first class. They include, in successive periods of my research, William Bossert, Robert MacArthur, George Oster, and Charles Lumsden. My role was to suggest problems to be addressed, to combine my intuition with theirs, and to lay out empirical evidence unknown to them. They were my intellectural prosthesis and I theirs.

5) Quality = design * content. When I am about to begin a difficult writing project, I will sometimes pull down a volume from one of three writers to gain a bit of inspiration: John Steinbeck, John McPhee, and E. O. Wilson. All are naturalists, all write with grace, concision, and elegance, but only one studies ants.

Brown Food Web Friday–Basiceros, the dirty ant

One of the great things about grubbing around in the litter of a tropical forest are all the odd ways, one finds, that creatures make a living. Taking the lemons (in a world that is, literally, rotting all around you) and making lemonade.

This is Basiceros manni (larger photo here), a slow moving predator that lives in tiny colonies of about 20 or so, nesting in soggy twigs and bits of rotten wood. Although it will eat a variety of insects in the lab, in the field it’s developed quite a taste for snails. Which suits its general habit quite nicely, as this thing pokes along at a snails pace and, if disturbed will curl up into a ball, armadillo like. A very crusty armadillo.

You see, Basiceros’s is covered with long modified spoon shaped hairs (see below) that, are great at gathering dirt, and up-close hairs resembling a frazzled feather that are dandy at holding the dirt close to the body. As a consequence, a nice young female leaving the nest (remember, ants are female collectives that only produce males for the sperm) will, over time, grow to resemble a clod of dirt (albeit one a fairly charming one).

We used to think Basiceros was rare. Now we know to be patient, look carefully, and wait for the aroma of escargot.