Tickbomb II: Ticks Strike Back

I have a number of crappy pictures for you today, as followup to some things I've mentioned previously.

First off, Scott got whalluped today by a king-size tickbomb, which gave me the perfect opportunity to take some macros for you all. (It's easier to do this kind of thing when they're crawling all over someone else's skin!) Fortunately, he noticed the blast before they migrated under his clothes, and was able to get the lion's share off with tape. I only got a chance to snap these in my room after dark, so the lighting is totally awful.

For what it's worth, I counted about 120 ticks on the bottom piece of tape. Here's a closeup:

Cute little buggers, eh?

While we're on the subject of parasite, here's Langsdorffia hypogaea, the parasitic flower I mentioned a few posts ago, and which was most helpfully ID'ed for me by Prof. Emilio Bruna in the comments. This one is much less likely to make your skin crawl -- at least as long as you have skin, and not, say, bark.

And finally, moving out of the parasitic and into the predatory, we have Pachycondyla somethingorother, a gnarly predatory ant that reminds me of that giant tiger-lizard-thing in Avatar. Egads, look at those mandibles! This picture is horrible and blurry, since Pachycondyla moves fast and I move slow / don't know what I'm doing with this lens. But somehow I feel like it's befitting this particular ant's image, like the jaguar lurking in the shadows...

Not too much else to report today. Caught literally a backpack-full of ants at Caça e Pesca, which are going to keep me well and truly occupied at the microscope tomorrow. Oh yeah, and there was some sort of sporting event today...

The mother lode

We got a present while tromping through the cerrado yesterday. Check these bad girls out!

Cephalotes clypeatus trying not to get aspirated.

Cephalotes clypeatus is a really unique, absolutely beautiful member of the genus. The pictures on Ant Web (linked) don't really do it justice: the cuticle on living specimens is very translucent, and forms a sort of membranous ridge around virtually the whole dorsal aspect of the animal. Combined with the striking amber-gold coloration, it gives something of a knight-in-shining-armor kind of feel to this species. (In the ridiculous Avataresque ant-based action movie I've been writing in my head, these gals are definitely going to play the role of shock troops / tanks for the good guys -- thrill as the canopy ants defend their ancient home against the marauding Ponerines!)

Anyway, Scott hasn't come across too terribly many of this species in the area, and they fall into an interesting spot in the phylogeny, so I was a little worried about coming home with a clypeatus-shaped hole in my sample set. But what did we find while out collecting pitfall traps, but a shining amber stream of C. clypeatus?

Fortunately for us (unfortunately for them), they were even nesting in a fallen limb that had gotten hung up on its way down. This means that we were able to collect what may be the whole colony. And it's a doozy!

Scott gently taps them out of the log, while I stand ready with an aspirator. There's a trick to doing this without inhaling sawdust. 

We were able to get through one of the four sections today. Who knew so many ants could fit in a log?! Although my sample requirements aren't anywhere near so big, by randomly sampling from the whole colony, Scott will be able to make some important observations about the distribution of size variation among workers; this in turn will play an important role in understanding the evolution of social structure and caste determination.

The end of the line -- C. clypeatus digestive tract, with midgut (left), ileum, and rectum. The little snakey bits are malphigian tubules; the little white hairs are tracheae. 

So that was my day -- cracking open logs, sucking ants through straws, and then staring at them through a microscope. Ahh, the good life...

Many thanks to Galen for squeezing off these shots in between frantic ant-wrangling!

It's not all fun and games; or, what I'm actually doing here

Fig. 1: the morning commute. 

You might think, based on the few posts so far this season, that "field" work for this marine-biologist-cum-entomologist consists entirely of traipsing happily through tick-infested woods, merrily climbing trees and peeing in all sorts of containers. And if my work day ended in the mid-afternoon, you'd be right. (I would dearly like for this to be the case, but alas!)

Oh no -- there is so much more fun to be had. Behold: the lab!

Fig. 2: pit of eternal despair lab station

The real reason I've flown halfway around the world, instead of just asking friendly scientists like Scott for some spare ants, is that I'm hoping to look inside the ants at the communities of microbes inhabiting their gastrointestinal tracts. Recent research by the fantastic Jake Russell, Corrie Moreau, and others suggests that ants with a mostly-vegetarian lifestyle (like yours truly!) have evolved unique partnerships with certain microbes. These microbes (some of which, incidentally, seem to be closely related to the bacteria that fix nitrogen in legumes) may be important in providing the ants certain nutrients -- such as nitrogen in the form of essential amino acids -- that are limited or absent in their plant-based diets. We humans also have important communities of microbes in our guts, that provide us all sorts of services that we're only just begging to understand and appreciate. I'm interested in how relationships in these microbial communities have evolved in concert with their host animals: have certain microbes evolved in parallel with their hosts over millions of years, or is it a big free-for-all with frequent partner swapping? Do the communities in ants look similar to those in humans and other vertebrates, and do they behave the same way? Are there some over-arching rules we can piece together governing these kinds of complex relationships?

Ants, for a bajillion different reasons that I won't go into right now, make really cool systems in which to study these questions. And we happen to have, at my research institution, the world's largest collection of ant specimens (really!). The thing is, most of these specimens aren't really any good for the questions I'm asking. When people like my office-mate E.O. Wilson (ed. note: I still have a hard time believing this) collected ants over the years, they spent a lot of time making sure the specimens were useful for ant taxonomy, and not a lot of time thinking about the microbes within.

While there's still a lot you can do with 'normal' ethanol-preserved specimens (Profs. Russell and Moreau's recent PNAS paper was done using mostly these kinds of samples), after a certain point you'd like to start using samples that were collected with microbes in mind. That's when things start to get crazy.

If you've ever hung out with a microbial ecologist, you'll get what I mean. Microbiologists are cut from something of a different cloth than your typical entomologist. Where insects might seem to be everywhere, microbes really are everywhere. As in, literally, everywhere. One must got to extreme, perverse lengths to try and manufacture places where microbes aren't. So if your questions is "which microbes are present in this sample?" and you'd like not to answer instead "which microbes are present in this sample, and on my hands, and in my hair, and on this bench, and just kind of floating around in the air, and also apparently thumbing their noses at Louise Pasteur and spontaneously generating from the aether" then you have to start being a new kind of anal.

Fig. 3: a new kind of anal. As in, an ant's dissected GI tract. a: ileum (where the magic microbes live). b: rectum. c: other bits.

So that's why I'm here, in person, with $400 worth of tweezers. In addition to catching a whole bunch of different ants, I'm also preparing them in all sorts of extra special ways in the hopes of getting good, clean information on the microbes living within. That means coming back from the field, washing up, sitting down in front of a microscope with my extreme tweezers, and dissecting the guts out of hundreds of ants (pictured above).

Hey, it beats flipping burgers...

Tickbomb!

I apologize for the lack of header photo on today's post, my lovelies. I forgot my camera at home today, and thus was unable to capture sublime images of the cerrado for you to enjoy. There is a picture in this post, but because of its semi-graphic nature, I'm going to bury it below the fold. For the squeamish, stop reading here, enjoy your cup of coffee that hasn't inexplicably been brewed in a high-molarity sugar solution, and spend the rest of your day secure in the knowledge that in suburban America, we lead a gloriously parasite-free existence. For the curious, read on, and behold the aftermath of... 

the TICK BOMB!

In which I first make contact

Cephalotes pusillus soldier and worker. Image cc Jon Sanders. 

Today was my first real attempted collecting day -- Scott graciously drove me out to Panga (the preserve) to poke around looking for Cephalotes. Unfortunately, it was cool, drizzling, and overcast, during which time most Cephalotes would apparently rather just stay indoors. So we didn't rack up a huge species count.

But there were ants! Tons of ants! Camponotus, Azteca, Tetraponera, Pachycondyla, Dorymyrmex, and even some Cephalotes, despite the weather. Pachycondyla marginata is particularly cool, an insanely shiny and dangerous-looking Ponerine (viz. 'badass') that makes a living raiding termite mounds, carrying away their children, and eating them. A quick Google suggests that they may also have magnetite-based internal compasses, the better to find you with, my dearies.

Most of what recruited to our baits were Azteca, Dorymyrmex, and Cephalotes pusillus (pictured). C. pusillus is apparently one of the more common and widespread Ceph. species, and was certainly abundant today -- hundreds were swarming out of their nests, facilitating a nice starter collection for me to practice on. Randomly snapping dead twigs also netted us a few C. maculatus and C. grandinosus, both of which look pretty radically different from pusillus and which I'm excited to get under the microscope.

Like many ant species, C. pusillus shows some fairly apparent worker polymorphism, with some of the sterile, wingless, female workers belonging to larger 'soldier' castes, and others to smaller 'worker' castes. The photo above, which is just about the best of my sorry first attempts at macro photography, serves as a fairly good illustration. In many Cephalotes species (not pusillus), the soldiers have specially developed, door-like disks on the front of their heads, which are used to plug the nest entrance in defense against attack by other insects and the like (they're not very effective against twig-snapping entomologists). The evolution of this polymorphism, and its effect on the diversification and ecology of the genus, form a big chunk of Dr. Scott Powell's ongoing research program.

Tomorrow, we're back in the field collecting from yesterday's pitfall traps. Never have I been so excited about spending a day poking through insects floating in cups of two-day-old piss. I'll keep you posted.

As formigas bom de Uberlândia, parte dois

Scott baiting a pitfall trap with honey water

After sleeping like a rock for twelve hours, I hopped out of bed, took a shower, put on my best khaki entomologist gear, and ran outside to meet Scott (and Flavio, a grad student at UFU) to go out to the field. "The field" this year, in stark contrast to the 2000m-deep hydrothermal vents of last summer, is a nature reserve about 45 minutes down a dirt road from the city. The cerrado (pronounced sa-HA-do -- in Brazilian Portuguese, double r's on the inside of a word sound like h's, single r's on the front of words sound sort of like Hebrew h's (think Challa), d's before e's sound like g's, terminal m's sometimes but not always sound ling ng's, and sometimes you just leave the last few bits of a word as an exercise to the listener, like in French) -- er, the cerrado is a an amazing habitat of tall grass and short trees that covers much of the interior of Brazil, as well as growing patches of what was once the Amazon.

Seriously, the trees are pretty short. As in, sometimes the grass is taller than the trees. This is awesome for studying arboreal ants because it means you really don't have to work too hard. Today, Scott and Flavio and I spent five hours carrying a step ladder around tying pitfall traps (little urine cups filled with honey water and, erm, actual urine as baits) in a bunch of different trees to survey the various kinds of ants living in the various kinds of trees. Since it's winter here, it was only a bajillion (Portuguese: pajilhâo, pronounced 'bush') degrees in the sun, which was nice.

Scott baiting a pitfall trip not with honey water

And the ant diversity in the cerrado is truly fantastic. While we were walking around, I got to see at least three different species of Cephalotes (the genus I'll be working on), two species of Pseudomyrmex, a couple Camponotines (including Camponotus sericeiventris, which is basically the biggest ant you've ever seen and apparently covered in gold dust), Azteca, Atta (the crazy leaf-cutter ants, in an honest-to-goodness trail through the woods), a bunch of generic Formicines, and a really badass-looking predatory ant whose name I've forgotten. 

Also today I saw infinite termites, a toucan, a dead cow, vultures, weird little parasitic flowers that sort of look like strawberries, holes that presumably contained armadillos, and terrifyingly huge funnel webs. The hole at the bottom of the funnel was about as big around as a banana. I hope to myriad deities that I never, ever see what lives in those things. 

More to come soon! Now it is again time for glorious, glorious bed.

As formigas bom de Uberlândia

I've finally made it to Uberlândia, and am ensconced in a delightful little place right next door to the University (Federal de Uberlândia, or UFU). Getting here was quite the trick. Here's what was supposed to happen:

(0 hours): Leave for Boston Logan airport

(2.5 - 6): Fly Miami

(6-9): Drink in airport bar

(9-18): Fly to Guarulhos International Airport, São Paulo, Brazil

(18-20): Clear Immigration, clear Customs, check in with TAM for my domestic flight

(20-21): Fly to Uberlândia

(21-∞): Drink in Uberlândia, catch ants.

Now, here's what actually happened: