Reed Magazine Footer
Link to Reed Mag  Home

Natural selection header
Chaw picture
Spider Woman
by Todd Schwartz
Crystal Chaw seems normal enough. But somewhere in her early childhood, something went terribly wrong. As a very little girl, she began to love spiders. Began to keep nasty, creepy spiders in her room — as pets. Kept them in jars, fed them, watched them stare at her with their oh-so-many little eyes—until she began to know what they were thinking, what they were saying to her. Communed with them until, one horrible day, her parents opened the door to find . . . Crystal had Kafka’ed into a giant tarantula!

Okay, so that didn’t happen. But she did, and does, have a passionate and rather unusual fascination for the order Araneae. Unusual, at least, for most two-legged creatures, who would rather have the smallest possible quantity of spiders in their vicinity.

“I’ve always loved them,” Chaw says now, in the glass and slimy-critter-filled confines of the research lab of professor Steve Black, her teacher, guide, and fellow scientist. “I guess it’s because my older brother was terrified of spiders, so I had a tool to use!”

The Reed junior still makes her arachnid-amour pay off: her developmental biology independent project and her senior thesis will explore an area of spider development that no other scientists have studied.

And that, of course, is the great strength of the Reed-style independent project, in the biology department or anywhere on campus: the undergraduate student has the opportunity to do real, meaningful science that would be the stuff of graduate school at most colleges and universities.

“The independent project was, for me, really intense,” Chaw says. “I loved it. It was student-driven, and that’s the way I learn best. I got to work closely with Steve [Black], which was great, and the project led directly to discovering what I want to do for my thesis. It was a lot of hard work, but I was just so excited to study spiders!” Bear in mind that this is a woman whose eyes light up when she explains that “if people and spiders were proportionate in size, we’d be dead!”

Spiders are, of course, extraordinary creatures, somewhere between miniature space aliens and eight-legged cans of insecticide. Some stalk and hunt like leopards, and most spin webs far stronger, fiber for fiber, than steel. They wear their skeletons on the outside like knights in armor. They drift long distances on the wind, carried by elegant strands of silk. A few produce toxins that can injure or kill you; most simply keep the local insect population at bay. Right now there are more of them in your house than you would believe.

And, it turns out, from a developmental biology perspective, spiders do something that no other animal does: a little trick called germ band inversion.

The end product of very early embryonic development is the production of the germ band, meaning that the part of the embryo that is going to make the central nervous system and muscles appears at one end of the egg as an elongated band—the “germ” of these critical organ systems. Then it gets strange. In spider embryos, the germ band splits down the middle, each half migrates around the horn, as it were, and both halves end up on the other side of the spherical egg. Go figure. The two halves rejoin, connect and fuse into the “definitive” germ band, forming the little leggies and all the rest. To the casual, non-spider observer, it seems like a completely unnecessary and complicating bit of developmental business. Chaw would love to find out how it happens.

In one of her two independent projects (in the other, she ran wolf spiders through a maze) Chaw attempted to learn if a gene important to fly development and segmentation had a similar pattern of expression in spiders, as the two species likely have a common ancestor. The findings? One, that you need a lot of time and patience to do good science; and two, that spider eggs are not very cooperative.

Among their many mind-bending capabilities, you see, spiders lay eggs that have an inner and outer shell, layers of wax and protein designed to let gases pass in and out, but not liquid. It took Chaw months of systematic work to figure out the chemical conditions that would allow her to see the cells and their contents.

Chaw and Microscope“No one has studied the mechanisms underlying this dramatic and complex movement of cells,” says Black. “Crystal hopes to learn whether the motive force for this morphogenesis comes from the germ band cells themselves or from the other cells in the embryo. For example, other cells could attach and pull apart the germ band. It’s a fascinating, original study.”

One that the very independent Chaw will continue soon, right after she finishes rampaging across campus, attacking defenseless Reedies with her eight hideous feet and giant spider jaws. Or not. End of Article

Back to Natural Selections main article

Reed Magazine Footer
Link to Reed Mag  Home