The Backyard Arthropod Project

Little Brown Job

When birdwatching, there are a lot of what S. calls “little brown jobs”, little nondescript brown birds (sparrows and the like) that an amateur doesn’t have a prayer of identifying on-the-fly. Well, there is the same problem with jumping spiders, like this one:

This is in the family Salticidae, which is a huge group of arachnid “little brown jobs” (about 4,400 species identified). There are at least two species around here (brown ones like this one, and black ones with white stripes that I hope to get a picture of later). Whether this is just two species, or two groups of umpteen species each, I don’t know.

These little guys don’t build webs, instead they charge around pouncing on things. As you can see in the next picture, they have really good eyes for a spider:

Isn’t that a sweet face?[1] They are believed to have full binocular vision (depth perception is so important when you are planning on pouncing on something), and they can jump a couple of inches. This particular one sat for the photos, and then abruptly leapt completely out of the dish and scurried off. They’re kind of like the ant lions in that they either don’t move at all, or move so quickly that they almost seem to teleport from point to point.

Continue reading ‘Jumping Spider’ »

Well, once again, it’s Tick Time. They hang out on tall objects (mostly dead weed stems and the sides of buildings) with their little front legs outstreched, and grab on when someone brushes past unsuspectingly. They don’t bite right away, so we usually find them when they are still crawling around looking for a place to latch on (at this time of year, every little tickle and itch becomes suspect). The ones we have around here are good old Dermacentor variabilis, which some people call a “dog tick” and others call a “wood tick”, while just about everybody calls it an “eeewwww” when they find it crawling up their leg.

Continue reading ‘Wood Ticks’ »

What timing! I’d just gotten the camera mounted to take nice, high-magnification photos of tiny things, and then S. tells me there is a pseudoscorpion in the bathtub, just *begging* to be photographed. So, here it is:

Then, we flipped it over to have a look at the underside:

And then, finally, zoomed in on one claw:

Considering that this little guy was only about 3 mm long, I think the photos came out pretty sharp. We figured that this should be good enough to get a full, positive ID, so I found an identification key to the pseudoscorpions of Michigan in the MTU library[1] . . . and had my illusions pretty much dashed. It turns out that you distinguish pseudoscorpion species from each other based on very fine details of the claws, and where exactly the sensory hairs (setae) are located. Unfortunately, even though the claw detail photo is pretty good, it isn’t good enough to count setae. According to the author of the ID key, even an expert might take as much as a week to prepare, dissect, and examine a pseudoscorpion to determine the species. There are supposed to be at least 29 species in Michigan, so the next ones we find might get taken in to the lab for a more thorough examination.

While a really positive ID isn’t practical from these photos, the fact that it was in the house (and, specifically, in the tub) means it was almost certainly Chelifer cancroides, also known as the “house pseudoscorpion” or “book scorpion”. This is a “cosmopolitan” species, meaning that we have carried it around the world and it pretty much lives everywhere that humans live. They are actually very common, but are rarely seen except when they, say, venture into the bathtub to get water. They spend the rest of their time eating other, even smaller arthropods (mites, clothes moth larvae, and the like), and generally get dismissed as being harmless and of no economic impact. They are reported to live for 2-3 years, which is pretty good for such tiny creatures.

Continue reading ‘House Pseudoscorpion’ »

The spider below had made a minimalist mesh-style web on the frame of our back door, so I took a bunch of pictures in-place with the improvised macro lens. By bracing against the surface of the door and taking lots of pictures, I managed to get a few that showed decent detail, but it was a lot of effort. Keep in mind that this is a little guy, only about 5 millimeters long. If there had not been a surface to brace against, there is no way I could have held the camera still enough to get an unblurred photograph.

But, not to worry! We have so much forgotten junk in the lab, there must be something that can be used to hold a camera steady, right?

Right! I would like you to meet “The Beast”, about 10 pounds of the finest brass machining the 19th century had to offer![1]

I found this old microscope frame stuck away in the back of a cabinet, along with a bunch of other microscope parts that were probably scrapped out sometime before I was born. This one was obviously the stage and mount for a dissecting scope, the mount is a nice 3-dimension positioner, moving up/down/forward/back/left/right with several inches of travel in each direction. With a bit of adaptation (mainly just getting a 1/4-20 capscrew to mount the camera, and drilling one hole so that the screw would fit), the camera and macro lens mounted up just fine.

Continue reading ‘Male mesh-weaving spider’ »

Come in to my parlor
said the spider

to the fly

Continue reading ‘European House Spider, Cluster Fly’ »