The Home of Midwood Science Research

The subject of this week’s scanning electron microscope image is a spider that crawled out from behind a painting in my parents’ apartment. Everyone knows that spiders have eight legs, but fewer people know that spiders have six to eight eyes. We originally thought this specimen was a wolf spider, but they have two large eyes on the top row and four smaller eyes on the bottom row. Our guest in the Midwood Science SEM has two sets of four equally sized eyes and is possibly a nursery web spider. There are currently over 450 defined species of spiders, but there may be four times as many species yet to be discovered.

Your basic spider has two main body parts — a cephalothorax at the front and an abdomen at the rear. In addition to the eight legs, spiders also have two long appendages for grasping food (called pedipalps) and two short appendages for injecting venom (called chelicerae). Spiders extrude silk for their webs from glands connected to a hollow set of appendages (called spinnerets) at the far back end of the abdomen.

Overhead view of the cephalothorax	Close up of four of the eyes	A slightly different overhead view showing the eyes, pedipalps (extended forward), and chelicerae (folded under the animal)
Underside view of the cephalothorax with a good view of the mouthparts (chelicerae closer to the mouth, pedipalps closer to the legs)	Underside view of the abdomen showing the spinnerets	Close up of the spinnerets

The length of a turtle’s claw tells us about the environment in which he/she lives. Turtles with particularly long claws suggest that they’re kept on soft surfaces. Turtles that are around rocks and rough surfaces get their claws naturally worn down. Female turtles that build nests prefer longer claws to make the building easier. Male turtles tend to have longer claws and they’re used to stimulate the female while mating. Trimming the claw of a turtle can easily be done with any kind of nail clipper or scissors, but only the sharp tip at the end of the claw should be removed. If you cut too deeply, the sensitive quick might be penetrated. (The quick is the vein that runs down the claw.) If penetrated, use a cotton swab to spread styptic powder onto the claw until it stops bleeding. (Styptic powder is a clotting agent.)

The first time I trimmed my turtle’s claws was a few weeks ago. This was before I found out about the vein and how much to cut off. As an inexperienced cutter, I took a pair of scissors, held out my turtle’s hand, and when I tried to cut about half, the turtle squirmed and tried to get away from me. I figured that it hurt him, so I tried cutting off a smaller portion. It was difficult to trim because the claw felt so dense. I finally cut if off, and let go. I could tell that he was relieved to get away from me.

For more turtle-related images, click here.

Image and text credit: Jasline Garcia