The joy of field biology

You can’t fake this smile for the camera.

An ecologist in the field is one of the happiest persons on the planet.

Advertisement

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.

Surely, surely, this can be modified into a field vehicle

Every primatologist would want one….

QOTD: Annals of field biology

“[Park officials and researchers]..occupy fairly different worlds. The former are government bureaucrats who, when based in the field, wear uniforms or, when based in government offices, suits and ties; the latter, by contrast tend toward torn jeans. The former think about issues like how to increase the flow of tourism in their park, while the latter would just as well get rid of those irritating tourists entirely, so that they can study their one species of ant in idyllic peace. editor’s note: Huzzah! The former tend to be pragmatic realists who function in a realpolitik world; the latter tend toward hysterics and causes and pride themselves on having no social skills. The former typically have wildlife management degrees, while the latter tend toward more prestigious degrees from fancy-ass universities and then, in a way that the former seem to find to be almost viscerally offensive, choose to live like Luddite pigs in leaky tents. And most of all, the former seem to exist merely to shit on the spirit of every park regulation they can get away with.”

Robert Sapolsky, A Primate’s Memoir

editor’s note part deux: A Primate’s Memoir captures life as a graduate student/field biologist perhaps better than any book. Furthermore, Sapolsky’s clarity and humor is a model for anybody who wants to write or teach better.

5 reasons why you should pick up a pencil and draw

Zeladoniac of Drawing the Motmot has a nicely illustrated post (natch) on a topic of some interest to anybody who studies the natural world for a living. Her “5 steps to better bird drawing”, might just comprise a new entry point in learning about your favorite organism.

I summarize (and annotate) her 5 steps below.

What a tropical forest looks like

Unlike, say, prairies or deserts where the light is often spectacular–think “Dances with Wolves”(….alright, don’t think too hard)–tropical forests are hard to capture with a camera. There is just so much stuff all dimly illuminated (only about 5% of the photons reach the forest floor) , save for the screeching light flecks that penetrate like laserbeams through ephemeral holes in the canopy. This is why the artist working with her pen and ink can often capture what the artist working with her digital camera cannot.

This image comes from Zeladoniac’s fantastic Drawing the Motmot. Keep yer eye out on this blog because apparently she has more like this somewhere. While you wait you can  browse through her eclectic postings on fossils, birds, natural illustration, and hair design.

Tempus fugit

I was in my pajamas, a child of the space race, watching Jackie Gleason one Saturday evening when a dark card reading “CBS News Bulletin” filled the screen and an announcer ominously intoned of breaking news.

It turns out three heros of mine had died in a horribly, horribly, mundane way. Astronauts Gus Grissom, Ed White, and Roger Chaffee were performing routine tests in the new capsule destined ultimately to take us to the moon. They lay strapped in, doors sealed, capsule fully pressurized with pure di-oxygen. They flipped switches, checked gauges, and generally went through the kind of dress rehearsals that train astronauts to perform their various duties automatically, with no hesitation.

At 6:30 PM EST Chaffee reported “We’ve got a fire in the cockpit.”. It was likely an electrical spark on some abraded wire–this was new technology after all. One would think that in a normal atmosphere of mostly di nitrogen gas the spark would have been noted and the offending circuit fixed. But this was pure oxygen and the flames spread. What’s more, in the pressurized command module it was impossible to quickly open the hatch, which required undoing 12 bolts and pulling the hatch in. The fire, and the increasing pressure (which eventually ruptured the capsule) made this impossible. Seventeen seconds later, Grissom, White, and Chaffee were dead of smoke inhalation. The heat had fused Grissom’s and White’s space suits together.

I suspect there is a large cohort of men and women that are doing science in part due to  these astronauts and the men and women who worked to send them into space and bring them home safely again. To be an astronaut, after all, you had to not only be physically fit and sharp of senses, you had to be smart. You had to get A’s in calculus and physics, we were told. So kids like me that would rather have had teeth extracted than do their math homework did so with the hope of big payoffs sometime down the road.

Even after Apollo 1, most of us longed to don the space suits, strap ourselves into those form-fitting seats, seal the cockpit door, and stare out those tiny windows as the Saturn 5 rocket below us rumbled into life. We imagined weightlessness, the black void, and the brilliant, unwavering light of the stars. And those of us who ultimately chose different paths still occasionally stare upwards on moonless nights and think of the heroes that allowed us to dream.

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.

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.