The First Days in Saint Paul, and Intro to Frogging

Moving in worked out all right, for all that the apartment is in an old two-story building with no elevator and narrow staircases with no dedicated parking. We were able to park the UHaul on the side of the building (because there's no way we could have parallel parked it in front of the building with enough space to get the ramp out behind it). All the furniture I brought fit nicely into the apartment, and my windowsills are now full of herbs.

I started work almost immediately in the lab, helping a post-doc run some phonotaxis experiments in one of the several sound chambers that belong to the lab. He ran the computers that simulate the signals and background noise, while I shuffled frogs back and forth from the incubator to the testing chamber. We're working with Hyla chrysoscelis, commonly called Cope's Gray Treefrog. It's pretty abundant and widely-distributed in the US. In Oklahoma, it's most often a mottled gray color (hence the name) but here in Minnesota, it's usually a brilliant green, leading some of my labmates to speculate about the name. They can change colors and patterns at will, so it's possible the green color is some artifact of the breeding season, or the capture location in scummy ponds. I'll have to do more research, but I expect I won't be able to avoid becoming a gray treefrog expert soon.

The second component of my job is to catch frogs. The frog-catching shifts run from 9 p.m. to 2 a.m., and usually take place at field locations about an hour from St. Paul. We go out in teams of 3 or 4, and spend a few hours trekking around the perimeter of frog ponds, looking for pairs in amplexus. This, as it turns out, is fairly difficult.

Firstly, there are about a million more males than either single females or amplexed pairs at any given time (this is what we might call a skewed operational sex ratio). The males sit around the edges of the pond, obscured by vegetation, or sitting on top of the duckweed in the middle, singing as loudly as their tiny vocal cords can take. The chorus is deafening. It's so loud sometimes that it's disorienting, especially in the dark, while walking on an uneven surface. The surface of the ponds is covered in a  floating plant called duckweed, such that you can't see where you're putting your feet or what submerged obstacles may trip you up. The mud is so deep and thick that when you lose your balance and try to reposition your feet, they stick hard and, with nothing to grab onto, you'll definitely fall over.

The males are singing to attract females, which is the basis of our research. Once a female has chosen a male, he hops on her back and they swim out a little deeper in the pond, to spend some time expelling and fertilizing eggs. The mating pairs of frogs don't sit on top of the surface like single males do, floating underwater mostly, with just their heads poking out. The end result is that the pairs resemble the multitude of sticks and lumps in the duckweed poking above the smooth surface. They're well-camouflaged, to say the least. While males are easy to find, we're only interested in mating pairs, as that's the only way to guarantee the female is in breeding condition and that her behaviors will reflect that.

Once you find a pair, the objective is to sneak up on them without making too much noise or too many ripples in the surface of the water. Those of you who know me will recall that I am particularly prone to trip on things and/or fall over for no good reason. I am therefore not the best candidate for tasks involving grace. The second part of the actual capture maneuver is to grab the pair from the water and put them in a tupperware container for safekeeping. That's trickier even than you might think, as the frogs are both nimble and slippery, and once they fall back into the water you'll likely not see them again.

Frog-catching is strenuous work. You find yourself walking through mud that sometimes comes up to your knees, trying to avoid tripping over root balls and submerged limbs in the dark. Also, you use about a hundred muscles in your lower legs that you never knew you had, trying to keep your balance in the mud. Other hazards await, such as the dreaded "frog eye" -- apparently the frogs have a toxin in their skin that can be terribly bothersome when it finds its way into one's mucous membranes. I have yet to experience this, but at the rate that I tend to adjust my contact lens when it's two o'clock in the morning and I'm tired, I can only presume I'll have the pleasure soon.

More tales of frogging later. As well as pictures of my adorable and majestic study organism. Because, really, who doesn't love treefrogs?