PLANTS | ANIMALS | ECOLOGY | FUNGI | GEOLOGY | GARDENING | TOOLS
Excerpts from Jim Conrad's
Naturalist Newsletter
from the May 30, 2010 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
TADPOLES
Last week we saw some of the jillions of tiny frog eggs left in a reflecting pool here at the Hacienda, which you can see here. You can see tadpoles from those eggs a week later above.
At this stage there are no hints of legs, though already the head is looking a little froggy, with the eyes clearly visible. The tadpoles spend most of their time grazing on algae at the pool's bottom, though frequently they dart to the surface, gulp air, then return to their foraging. In most tadpole species lungs develop around the time of leg development. A profound change taking place now, invisibly, is that their intestines are changing from long and thin, appropriate for a vegetarian diet, to short and thick, which will be needed by the insect-eating adults.
The name "tadpole" is from the Middle English "taddepol," composed of the elements "tadde," for "toad", and "pol," for "head." Thus a tadpole is a "toad-head," which pretty much describes what appears in my hand. I've always called them tadpoles but I read that others call them "polliwogs" and even "pollywiggles." Both of those names are from the Middle English "polwigle," made up of the same pol found in tadpole, plus "wiglen," the verb for "to wiggle." Thus a polliwog is a wiggling head.
Wikipedia provides more information on tadpole development on its Tadpole page.
from the June 20, 2010 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
TADPOLE UPDATE
In the May 23 Newsletter I showed you frog eggs in one of our reflecting pools, and the week after that we saw the resulting very numerous tadpoles. They still are showing no signs of legs, but now a month later other important changes can be noted.
The main visual difference is that the tadpoles are bigger, and there are much fewer of them. I know from reading that right now massive changes are occurring inside their bodies, especially as their long, slender, vegetarian guts change to the short, thick guts needed by insect-eating adult frogs. A question I've wondered about was whether, as the tadpoles grew more froglike, they might start eating one another...
This week I thought I was seeing tadpole cannibalism when I snapped the shot shown below:
At first it looked like a tadpole was nibbling on the body of a dead, tailless tadpole, but once the image was on my laptop screen it looked more like it was feeding on white, filamentous fungus emerging from the dead tadpole's body; it's hard to say. The nibbler was certainly nibbling very aggressively for several minutes, though.
On the Internet I read this: "The role of tadpoles in aquatic systems is gradually being redefined, with recognition of their importance as carnivores and scavengers rather than strict herbivores and detritivores." A tadpole study's abstract is online at http://eco.confex.com/eco/2007/techprogram/P3707.HTM.
Maybe a raccoon or similar animal decimated the pool's tadpole population, or maybe most of them died one night when the high algae concentration removed so much of the water's oxygen that the tadpoles died of asphyxiation. Or maybe now that the pool's tadpoles are getting their short, thick guts in place, they're starting to eat one another...
from the July 4, 2010 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
TADPOLES WITH LEGS
Since May we've been watching tadpoles develop in one of the Hacienda's reflecting pools, where frog eggs were deposited on or around May 17th. As of this week the first tadpoles have appeared with legs, as shown below:
Maybe only one out of 50 tadpoles has legs now, and the ones with legs don't seem to use them. The legged tadpoles swim about simply dragging their unmoving appendages, which probably disrupt their bodies' aerodynamics and cause a bit of drag.
It's hard to believe how many tadpoles still live in that pool. My cupped hand rising from a random spot at the pool's bottom retrieves maybe a dozen wiggly critters after many more have slipped away as my hand rises. The pool's water is emerald green with algae, so apparently that's the tadpoles' main food. But before long the tadpoles' current slender intestines will grow short and thick the way a carnivore's guts are supposed to be, to serve the insect-eating frogs the tadpoles will become. We'll just have to see how that problem resolves itself.
from the August 18, 2002 Newsletter issued from the woods near Natchez, Mississippi, USA
A DISHPAN CROWDED WITH TADPOLES
In the two previous Newsletters I told you how on July 31 frog eggs were laid in my dishpan. Since then, each day activity there has increased, and now things are getting crowded.
The day they were laid I realized that the dishpan could never support so many tadpoles if all the eggs should hatch, so I dumped what I thought was all the eggs into a small, water-filled, metal tray salvaged from the bottom of a junked refrigerator. The tray is kept on the ground next to the trailer to supply water for birds, butterflies, raccoons and the like. Obviously I didn't succeed in dumping all of the eggs for today about 200 tadpoles wiggle in my dishpan. Interestingly, in the ground tray where I must have deposited several thousand eggs, there are only two or three tadpoles. Something has controlled tadpole population there, but not in my dishpan.
My dishpan has a bit of algae in it (their main food) and occasionally I thump a crumb of cornbread into it, which the tadpoles seem to relish. However, each day as the tadpoles grow the algae diminishes markedly and I am less disposed to sustain 200 incipient frogs by feeding them cornbread -- especially since my meal is running low and I dread the trip to town.
There seems to be a morality play in the making here. I'm not sure how it will resolve itself. I'll let you know.
from the August 25, 2002 Newsletter issued from the woods near Natchez, Mississippi, USA
CUCUMBER-EATING TADPOLES
Last week I mentioned how the tadpoles in my dishpan like cornbread, and how my cornmeal was running low. The food problem has been solved by discovering that tadpoles relish overripe cucumbers and squash -- something of which there's plenty here.
The tadpoles swarm over slices of cucumber and squash wiggling their little tails furiously like so many contented piglets. Well, maybe it's not contentment, but rather the need to keep their bodies positioned so that their under-the-head mouths keep in contact with what's being eaten. I like to think of it as contentment, though.
If a thin slice of cucumber is placed into the water it will be attacked not only by tadpoles but also by those aquatic larvae of mosquitoes known as wiggletails. Just like tadpoles, the wiggletails work their rear ends vigorously as their mouthparts are pushed along the cucumber slice's surface.
from the September 1, 2002 Newsletter issued from the woods near Natchez, Mississippi, USA
TADPOLES OVER THE EDGE
During a late-afternoon rain on July 31, frogs left eggs in the dishpan in which I wash next to my trailer door, and each week since then I've reported on the developing tadpoles.
About an hour after I issued last Sunday's Newsletter a storm came up and simplified the dishpan's overpopulation problem. The dishpan lies beneath an awning from which water dribbles into it. During last Sunday's rain the dishpan overflowed. I stood there in the downpour watching tadpoles flow over the edge to certain death on the ground below. I let this happen because of my realization that there were just too many tadpoles there. Even if all the tadpoles somehow made it to adult frogdom, the local ecology could never support so many frogs. I watched as about half my tadpoles went over the edge.
Standing in the rain with all my conflicting feelings, this question occurred to me: Am I not to my tadpoles in their dishpan approximately what the Creator is to us humans on Planet Earth?
Having that insight so vividly placed before me, and remembering some times in my own past when I could have used a bit of divine intervention, I thought: "Obviously the Creator has made us tadpoles and humans this way, but why wouldn't it have been just as easy to formulate us so that neither tadpoles nor humans are predisposed to commit the excesses and errors that get us into these awful situations? Why build a frog whose vast majority of offspring must die before reaching adulthood, and why build humans programmed for the arrogance and aggression that's screwing up our world right now?"
I cannot recall the path my mind took from the moment of that thought, but I can say that leading directly from it suddenly there arose a flash of insight. For perhaps a thousandth of a memorial second I understood that the moment the Creator cleaved matter from primordial energy, the die was cast for things being the way they are, frogs and people. I understood clearly that in any Universe in which matter existed apart from nothingness or pure energy -- where there was stuff of touch and movement, stuff that interacts and evolves -- then tadpoles over the edge become inevitable, and so do hermits with some hard memories and hemorrhoids.
During that micro-moment in the pouring rain I understood profoundly that without pain there cannot be pleasure, without darkness, light.
An hour after the rain, walking around still stunned by the intensity of my insight but already gradually losing the thread of thought leading to my discovery, I noticed that ants were tearing at the drying-out tadpoles on the ground below my dishpan table. Up close I even smelled the fishy odor of tadpoles coming undone.
Yet, it all seemed right. If during this last month my emotional currency had been invested in ants instead of tadpoles, I should now be as close to the ants as I am with the amphibians. And I would be rejoicing with them that during this recent rain these gelatinous packets of dark, speckled protein plopped onto the ground from above, a kind of manna from heaven, just what the Queen and her colony needed.
And I stepped into the trailer laughing at the world, laughing at myself, just laughing.