SEM Saturday

Last week I got a message that there was going to be a scanning electron microscope demo for some kids at a conference in Portland, and they were looking for an entomologist who could tell the kids something about the bugs they were going to be looking at. This sounded agreeable, and I met with one of the local organizers in the Chemical Engineering building to learn how to use the machine.
It is a fabulous new type of SEM, it takes almost zero prep and very little training, it's about the size of a big desktop computer, and it stores the images directly onto a USB key.
I was left to play with it on Thursday evening, and examined a variety of bug heads, pincers, and legs, but it was immediately evident that I was still thinking too big. The biggest focal area for the microscope was something on the order of Roosevelt's earlobe on a dime. I spent Friday afternoon prepping a dozen samples for the kids to look at, stripping minuscule bits and pieces off all the insect specimens I could get my hands on.
Saturday came and we left for Portland at 6:30am. We got to PSU and there was coffee, fruit, and pastries for all. Parents and kids were arriving from the four points of the compass: this was a Nanotechnology conference which I gathered was a bigger deal that I had imagined.
After the keynote speaker had maundered his two cents, there was a brief period of chaos while the kids and parents assorted themselves into their proper groups. This was all the time I had to get to the microscope lab, introduce myself to the rep from FEI optics, and arrange my samples before kids streamed in, expecting entertainment.
The first slide I had was a sminthurid collembola, a goofy-looking soil goblin. Unfortunately the vacuum inside the scope lifted the tiny creature into Limbo and we never saw him again. Here is someone else's image:


After that I found a water strider foot from a specimen collected in Finland. The feet of these animals are coated with oily hairs for standing on water membranes.


At the bases of the hairs are slits that perpetually ooze oil.


From the same part of Finland, I also had a pseudoscorpion.


Here is the tip of his claw. Notice the trichobothrium, the sensory hair, in its flexible crater. The points of the claw are hollow and contain sacs of venom.


A top view of his chelicerae, his small chewing claws.


I noticed for the first time these little flappy hands on the front of the chelicerae.


A dragonfly from Arizona was mostly too big to get good images, but here is a claw from its foot:


This is the junction of the tibia and first tarsal segment of Abedus herberti, my favorite waterbug. It looks like a lichen-covered boulder.


Here is a scorpion, Vaejovis vorhiesi, that I found on my pillow in Arizona in 2004. I've been carrying it around in a little tube of alcohol, but it finally started falling apart so I thought this would be a fitting end to years of service.


The frenetic activity of the demo kept me from taking all the pictures I wanted to (the poison duct at the end of the stinger was particularly evocative!) but I got a few good ones, like this top-view of the chelicerae. These are the small chewing-claws that the scorpion uses to tear the goodies from the exoskeleton of their prey. Note the interlocking thumb-finger arrangement.


All scorpions possess pectines, comblike chemosensory structures on their undersides, tucked behind the last pair of legs. This scorpion is glowing in ultraviolet light:


The pectines are covered with little pebbly structures that taste the sand for chemical clues.



That's all I have at the moment. I'm going to talk to the FEI people about maybe flying me back to Portland after New Years and letting me prep some demo slides for them, in exchange for hours with the microscope and the little gold-vapor gun (which makes for much nicer pictures than these.) I was supposed to go to Florida to chaperone some Austrian high school kids around Orlando right after Christmas, but the character who's running the show is mysteriously prevaricative.