The Nexus of Amplexus

When the weather gets warm and the rain starts falling, usually that is a sign of what is to come: a chorus frog breeding event. The day will feel a little muggy, depending on your standards for mugginess it might border on gross, and then the clouds will darken. In the southeastern United States you get powerful storms, storms where all the rain you could imagine shoots out of the clouds in a violent burst. It is like someone tore the bottom right out the clouds themselves, allowing their innards to fall freely to the Earth, only in a continuous manner. And maybe with a little more force. Seriously. For an arid climate native the first real storm experience out here is eye-opening. To me it was some flash flood level storm action that first time in South Carolina. Now, on my third tour of duty in this part of the country, I am sort of adapted to it. So are the chorus frogs.

The species I am working with, Pseudacris feriarum, seems to rely on the warm weather/heavy rain combination in order to continue their lineage. They come out to their roadside ditch breeding ponds in droves during such weather events. Thus, a huge part of my job is to follow the weather and take advantage of what can be a rather small window of opportunity to locate breeding frogs. They do not generally hang around for long to mate. Eggs must be laid so tadpoles may develop and metamorphose before the newly filled ditches dry up.

But enough of the science behind it! I have a story!

Near Tallahassee, deep in the Apalachicola National Forest, somewhere north of Sumatra (pronounce the first "a" like the start of the word "apple" and you will know how to properly say that dumpy little town's name), there is a place called "Plague Puddle." It is so named due to a reported plague of frogs a few years ago when Dr. Lemmon and her husband, also a Dr. Lemmon, went out looking for mating pairs of frogs. Anyway, upon my arrival this winter I was told to visit this place when the next local storm hit.

Well, as you already guessed, that next storm did hit. I was just getting back into the swing of things as the crew leader, and my first meaningful decision was to have us split up into two vehicles for the night ahead. John and Alyssa were in one car, and myself and lab member/honorary crew member of the night Sarah took the work truck. John's car would scour the long ditches along the highway heading toward my destination, which was of course Plague Puddle. The multi-car approach would be advantageous for hitting more breeding sites at once, improving our odds of catching many frogs in amplexus (remember, that means mating).

It is a long drive to Plague Puddle from Tallahassee. Maybe an hour and a half. The turn off the highway is marked by a sign stating "WATCH CHILDREN." Not too much farther. As we approached the normal Plague Puddle parking spot I totally screwed up and drove past it. I am a crew leader, not a super hero. I found a convenient spot to turn around that was not too close to the creepy stilt-house community of hunting shacks down the road. Windows down, we lulled to a halt next to our destination from the other direction. And that is when it began. SO MUCH CHORUSING. The frogs were going wild! Even from the road they were impressively loud. It was impossible to distinguish the individuals calling within the chorus. Were there 30? 40? 50? More? Who knows.

(The video below is a daytime chorus of about 20 male Pseudacris feriarum in Alabama. Just double or triple it and you will begin to understand Plague Puddle.)

Safety comes in numbers

We quickly exited the truck, equipping boots and headlamps, and stuffing our pockets with our Ziploc holding cells for the frog pairs. As Sarah and I crested a small hill we saw the first pond, a crater-like wasteland with almost zero emergent vegetation. Basically crappy habitat if you ask me. In that little cesspool we found a fair few pairs of frogs in amplexus. Some were floating lazily in the middle, forcing me to sacrifice my comfortably dry feet for the sake of science. Other pairs were more kind, clinging to the few little stems poking out near the water's edge. We cleared the place of all its happily joined lovers in minutes. Then it was decided, almost without words, that we must go a few more yards into the woods to tackle the booming chorus at Plague Puddle.

The hubbub was about as close to deafening as a frog chorus can be. It goes beyond description. When there are that many male frogs calling so loudly they will completely ignore intruders, even those that stomp into the water with bright lights on their heads. My best explanation for this behavior is that they figure their odds of being the one harmed is quite low, so why quiet down? Besides, there is mating to be done! There might not be another chance. I crept off the shore into the shallow water with my eyes peeled. Immediately: "PAIR! Another pair! Holy @#$% another pair! This is crazy! Are you seeing this? Can you even hear me?!" It was a true frenzy. Pairs of frogs seemed to show up out of nowhere. One stick could have 2 or 3 of them, just biding their time, being all amplectic and whatnot. Some pairs would emerge from the depths without warning, sometimes right in front of me. I used up all of my bags before taking 10 steps. As I scrambled back to the truck for more Sarah continued collecting pair after pair of the hyped up little frogs. Fortunately I had some random extra bags (from Ecuador) that were giant and vacuum sealed; the type you must fiddle with incessantly to get open, and then tie up in order to close. It can be a 30-second process for each bag, if it behaves. Perfect... At one point I was frantically ripping at a bag to get it open as I saw 1, wait no 2, uh oh 3, really? 4, 5, and finally 6 pairs sitting in the open in front of me! I did my best not to completely lose my mind. Remember, this is all time-sensitive, and each pair goes in a separate bag. Once we catch a bunch of these frogs we must go back to our trailer, set up the testing chambers, and do a lot of preparation work before even beginning our testing that very same night! Oh the energy drinks that were to ensue!

Pair in the making?

I hurried. Of course I had to watch events unfold in front of me as I struggled. There might be another pair ready to surface from the piney deep (lots of pine needles in the pond), and I would need to catch them all after the other 6 already plain in view. That was when I saw something new and exciting. I might even call it tremendously fascinating for my best David Attenborough impression. It was something I did not see all of last field season. I bore witness to the formation of a mating pair! It might not sound that exciting, but I swear it was. Here is the scene: I was mumbling something about "all these stupid frogs" and their needing to shut up. I saw a jubilant little male calling from a floating stick in the water no more than 2 feet from my right boot. He called and called, his vocal sac inflating and deflating rapidly. The surrounding chorus was so loud that I could hardly make out his song distinctly. He was far from alone out here. Apparently a nearby female did not have as much difficulty picking him out from the bunch. I saw the bloated, egg-filled female frog bumble along in the water in his direction. She met him on his floating debris, facing him with her head turned, aiming her right tympanum (frog ear) in his direction to make sure he was the one. I watched with anticipation. Nothing. It felt like several seconds had gone by, and he still had not made his move. Come on frog! She wants you to jump on her and get it started! Still nothing. Then out of nowhere Miss Feriarum pile-drived her head into him two quick times. It was as if she was saying, "Okay, I made up my mind. We should mate." He responded by jumping on her back and clasping around her body instantly. PAIR! I tried to explain to Sarah what just happened. The chorus was too loud for an eloquent description.

I triple frog dare you!

Events like the one I just described are what make this job worthwhile to me. The timing of all the elements is so crucial that it is rare to enjoy such an up-close display of froggy courtship. I am often in too much of a hurry collecting frogs to enjoy the unique time and place I am occupying. It is not every day that you see this stuff. A booming chorus of frog love must be properly appreciated. On that night I got it right.

An interesting side note: Sarah found herself a silly little trifecta of frogs that same night. It was an awkward stack of male-male-female amplexus. This happens in loud choruses, probably because the males get confused and are too amped up to think twice about who they are jumping on and clasping. The cause could also be that the topmost male was trying to steal or reclaim a mate. Either way it was a really cool find, of which Sarah was proud. If I had a frogging ego I would be jealous of her find... I swear I got over it.

Alright, I would like to thank you for reading this account of my first experience at Plague Puddle. I have done a lot more in the field since, and I will try to put together my next story while I have the time. Writing a blog is tough when one oscillates between the diurnal and nocturnal lifestyle. I hope to crank another one out soon!