Dissertation

So, I'm writing a dissertation. Supposedly. Supposedly it needs to be finished in less than two months. Supposedly I am the person who will accomplish this feat. While teaching 5th-grade science. Here's what's killing me: I'm not working on it. I'm freaking out instead.

In undergraduate, back when I was an English major, I would read something the week before the big paper was due. Then I'd spend an afternoon in the library reading a few sources about things I didn't understand in the thing I read. Then I'd sit down and write a paper from start to end. I'd lay that paper like a golden egg, the product of a week's worth of reading and thinking and composing in my head magically squirt out of my brain's cloaca all at once. I'd put myself to bed and in a week or so get back a paper full of glowing praise. It made me feel very clever.

The dissertation is nothing like those old English papers. The dissertation is built word-by-word, a stone castle perched on a 6-year-old garbage heap of data. Every step makes me feel stupid. Every word is scrutinized by the perfect scientist who lives in my brain and judged. Rarely does a single sentence escape the retreating cursor.

I called Kelly about my sudden and acute dissertatiophobia. She commanded me to stick butt to chair and do something. So I tried it. I did one little task. Then I did another. Doing something made me feel loads better, and I worked the rest of the day, taking a break for a late lunch and a late dinner before talking to Kelly again.

She reminded me that I'd need to finish one chapter per week if I want to have a full draft by May for Jim. I have enough of a start on two of them that finishing the two chapters won't be too bad. It's the unknown chapters that scare me still. Is that part of the garbage-pile firm enough? Or will the west wing collapse under its own weight. Only time will tell! Short, brief, momentary time. Finish this first part by Wednesday? Yikes! But it can be done.

Giant stick insect rediscovered, fails to win beauty contest

Photo by Patrick Honan/Nick Carlile.

You might have seen this Giant Stick Insect Article from NPR recently. It tells the story of a crazy large stick insect from Australia that disappeared in 1920 and was thought to be extinct, only to be re-discovered clinging to life on a tiny rocky island in 2001. Scientists brought a few of them back home and managed to breed them in a zoo.

Great news, right?! Totally sweet insect saved from extinction! Now we just have to get rid of the rats that ate all the original population and we can once again have these massive tree-lobsters roaming all over the place!

Except...
"Will ordinary Janes and Joes, going about their days, agree to spend a little extra effort and money to preserve an animal that isn't what most of us would call beautiful?" (says Robert Krulwich in the NPR article)

Should survival be a beauty contest?

Wondermark comic about animal language

Here is a link to the comic


I love Wondermark. There are a number of highly amusing science comics by Malki that rank among the best comics I've ever LOL'ed at. This is no exception. Here, encapsulated in a simple webcomic, is all that I have wondered about human and animal 'language.' We consider ourselves sophisticated users of language because we have things like arbitrary signs (like beeping for instance), ability to talk about displaced or non-existent objects, and infinite flexibility of expression. However, these very things that we consider to make our communication of a higher order than the rest of the world, also makes our communication more obfuscated. A wolf's growl communicates in perfect clarity and simplicity across multiple species. No one needs to learn what it means, and no one needs any more information than it provides.

Wetas

Above and Beyond in the Down Under: Cool Creepy Crawlies.
The snow today reminds me of the alpine weta, a creature that can survive being frozen solid. May we all weather our trials with the same cool-headed-ness.

Plants (who knew?)

You may be surprised to find that now we're going to talk about the communication systems of plants. Turns out plants can be pretty smart for creatures without brains, nerves, muscles, or specialized sensory organs. When evil herbivores like caterpillars start to munch on plants, plants do not have the option of running away. Instead plants stand their ground with a full arsenal of defenses. Many of these defenses have a direct affect on the herbivore. Direct defenses are things like antifeedants which deter caterpillar feeding, toughening agents that make the plant tissue hard to digest, hairs called trichomes that make the plant tissue spikey and can secrete noxious chemicals, proteinase inhibitors which stymie digestive enzymes in the insect gut, and caterpillar poisons which can kill 'em dead. Direct defenses are the bread-and-butter of plants under herbivore attack. There is another kind of defense, however, called indirect defenses - a way to "call in the cavalry" so to speak.

Most every insect has an arch-enemy - a parasitoid. Caterpillar parasitoids are usually tiny wasps. When a parasitoid wasp finds its host caterpillar, it will lay its egg(s) in the caterpillar. The parasitoid wasp's eggs develop inside the caterpillar and will eventually, Alien-like, pop out of the caterpillar to pupate and complete their development into adult wasps. This is a pretty painful process for the caterpillar, which is essentially converted into a wasp-incubator and then dies. You may be wondering how a little wasp finds the right caterpillar. It's a bit like looking for a needle in a haystack, right? If only the haystack would tell you where the needle is hidden! Well, that's essentially what plants do when they activate their indirect defenses. In response to specific compounds called elicitors in the caterpillar's spit, the plant will launch a beacon consisting of a unique blend of odors (usually a blend of terpenes). Parasitoid wasps are attracted to these odors, and come flying to aid the plant by parasitizing the caterpillars trying to catch a meal off the plant. The smell of the beacon is only activated by the caterpillar's spit, and is unique for each species of caterpillar, providing a reliable signal for the parasitoid wasps to find their specific host. The plant-insect communication system really works because the parasitoid wasps are very sensitive to odors and very good at associative learning. They can associate just about any odor or complex odor blend with the stimulus of laying an egg in a caterpillar. Once they've had the experience of finding caterpillar hosts on a plant that smells just so, they will continue to seek out that smell to find more caterpillars. It's a win-win - well, at least for the plant and the wasp.

So we have a great example of cross-kingdom communication. Why don't plants talk to each other? If you were a tomato plant like one in my garden, crowded up against your neighbors, you couldn't help but 'overhear' when one of your neighbors gets attacked by an herbivore by sensing the parasitoid-calling odor beacon and other compounds that are released when a leaf is damaged. And if your neighbor is being munched, odds are good that you might get munched soon too. Probably should go ahead and load your guns. This is the theory behind priming - that the perception of herbivores feeding on neighboring plants allows undamaged plants to be primed to mount a faster, stronger defense response when the herbivores eventually come for them too. Interestingly, the existence and importance of priming in various plant systems is still in question. For one, plants aren't real cooperative or social creatures, so we don't really expect them to be selected to lend a hand to their neighbors. Also, it is not necessary to assume that just because you can smell the smell of a damaged plant you will certainly be next on the herbivore hit-list. In addition, some have scoffed at the idea of priming just because plants don't typically come equipped with noses with which to sense odors from neighboring plants. Though, is communication dependent on having a mouth and tongue to make words or ears to hear them?

Ichneumonid parasitoid wasp image by Tony Wills [http://www.gnu.org/copyleft/fdl.html], CC-BY-2.5

Lighting Bugs: The Flash and the Furious

Photo "Star Trails and Fireflies, June 22, 2009" by Steve Irving, used with permission

Nothing quite expresses the sublime joy of watching fireflies paint the night sky with their glowing tails. Few realize, however, that their beautiful language is for the purpose of mating. Male fireflies take off just after dark, emitting a telegraphic pattern of flashes that can vary in intensity, shape, length, and periodicity. Each species has a unique flash pattern which the female recognizes among all the other flashes as the one belonging to her species. In between pattern repeats, the male waits for the female to respond with her own characteristic flash from her hiding spot in the vegetation. When he catches sight of her come-hither flash, the male circles back, repeating his flash pattern and waiting for her to repeat her response. This way the male and the female firefly call to each other in the dark until they locate each other and consummate their romantic conversation.

Fireflies are beetles belonging to the family Lampyridae. They spend most of their lives as larvae (glow-worms), living in dark and muddy places and preying on snails. Like moths, their adult lives are short. Like moths, many beetles related to fireflies will use sex pheromones rather than light to attract their mates. The unique bioluminescence of fireflies, however, allows them to wait until dark (when birds and other predators are asleep) to come out to mate. Specific flash patterns make the species immediately identifiable from a long distance at night. The frequency and intensity of light flashes can also communicate information about the male's quality as a mate. These advantageous aspects to light communication has led to the evolution of light-based sexual signals four times in the firefly lineage.

The flash dance of fireflies can be exploited, however. If you're skilled with a small pen-light you can trick male fireflies to land on your hand by flashing back at them as a female firefly would. Females of the genus Photuris have also learned to pull this prank on male fireflies. Photuris females will call to males of other firefly species, but not for mating. These femmes fatales are looking for a snack. The male, oblivious to the fact that the female below is not of his own species, flies straight into her welcoming jaws.

Figure of firefly flash patterns by J. E. Lloyd, University of Florida from Fireflier Companion (1998) 1(4): 56.
Image of Photuris female munching on male also by J. E. Lloyd.

Moth Madness

Adult moths live much like many college students in that their lives revolve around sex. During their very short existence, their only imperative is to reproduce. To this end, they have a streamlined chemical communication system. The female moth produces a unique chemical compound which is known as the sex pheromone. This arousing perfume is produced in glands in her rear end in extremely minute quantities (picograms (10^-12 grams) per hour). The male's antennae are attuned to this odor and can sense her pheromone from afar. Like a bloodhound, he homes in on the female. Actually, the male locates the female by following her scent upwind. No need to even be able to follow a concentration gradient or make interesting small-talk. It's dead simple.

Once male finds female, close-range signals such as compounds present on their cuticles can tell the moths something about each other and their qualities as a mate. When you don't live long, though, it doesn't pay to be picky. The response of male moths to sex pheromones is so predictable, sex pheromones are a great way to control pest moth species without pesticides. A trap like the one in this picture uses an artificial lure imbued with sex pheromone. Males are attracted to the trap, but instead of finding a lovely lady, they find a surface covered in killer sticky slime.

Another way of controlling moths with sex pheromones is a method known as mating disruption. The sex pheromone is often loaded into little plastic tubes like this one that can be hung from trees. Sex pheromone produced by the real moths will be mixed with synthetic pheromone being produced by scads of tiny plastic tubes. Flooding the whole area with sex pheromone makes it very hard for males to locate females. Even when they do manage to find the odor source, a bit of plastic is a poor reward for following a odor plume.

The simple sex pheromone communication system of moths does not constitute a language. But while simple, it is extremely effective, providing a reliable, low concentration, long-range signal requiring minimal energy investment for either the sender to produce or for the receiver to interpret. Moths need no online dating service with its 29 dimensions of compatibility. They already have a language tailor-made for fast and easy hookups.

Pheromone dispenser photo by Eugene E. Nelson, Bugwood.org, used under a Creative Commons License.