Friday, December 25, 2009

Crab Spider Day 2

Persephone did not seem too fond of the fly, so I gave her a honeybee today, which she quite readily snapped up and has been devouring for over 16 hours. I took some photos, in which you can see how much her abdomen has engorged, indicating how hungry she was before she came under my care. Other than that, no notable changes. It is winter here in California, so despite insect forays I have not come up with many interesting specimens.

Also, here is some information from my field guide about Goldenrod Crab Spiders - Females tend to be yellowish-white with crimson streaks on each side of the abdomen, and a reddish-brown stain between the eyes. The female's legs tend to be pale, they inhabit meadows, fields, and gardens on daisies, goldenrod, and other white or yellow flowers. They are found throughout North America and Canada. They prey on flower-visiting insects, hence why she didn't like the fly very much. They administer a bite that injects fast-acting venom, and they can capture insects much larger than themselves. The females protect an egg sac for a time, but the female usually dies before the spiders hatch (usually 3 weeks after being laid).

Thursday, December 24, 2009

Experiment in Spider Rearing

Well, my friend found a crab spider in her car, and I had been considering taking on a spider as a pet, so I decided this one would be as good as any. Plus, it being a crab spider, it does not spin webs and instead sits on flowers waiting for a passing insect, so it's a lot less messy. I have it set up on a stalk of rosemary, and it has already captured its first meal - it seemed quite happy about it. The first name that came to mind was Percival (Percy for short) - I have no clue why, but that name has stuck.

Araneae; Araneomorphae; Entelegynes; Thomisidae; Misumena vatia (female)
Common Name: Goldenrod Flower Spider

As for its actual name, it is a crab spider (family Thomisidae) of the genus Misumena based on the bugguide explanation.

Misumena is distinguished from Misumenoides and Misumenops (two other common flower crab spiders) by having eight readily visible eyes, all approximately the same size, and the lateral eyes situated on tubercles. I just checked under the scope, and Percy was good and sat there looking straight up at the lens, so I got a good look.

often has a prominent ridge separating the rows of eyes into four posterior and four anterior, but most characteristic is the "mustache" or lateral tubercle/prominance just above the chelicerae (the pair of appendages to which the fangs are attached).

has the lateral pair on tubercles like Misumena, but the posterior lateral eyes are slightly larger than the medial pair.

Crab spiders are capable of changing their color to match their surroundings, and include morphs such as white, greenish, yellow, with varying degrees of brown and black. I wonder if Percy will change colors now that it is on purple rosemary flowers, and green leaves rather than the whitish interior of a Prius. I would love to find a green lynx spider, I think they are simply gorgeous, but alas I doubt I will find one again soon. I spotted one once in San Diego - with any luck I'll run into one again and be able to keep it as a pet for a bit. Today marks the first day of taking care of Percy - we shall see how long it lives.

*Edit: It appears that Percy is a FEMALE Goldenrod Crab Spider, so I am going to change the name from Percy to Persephone. Special thanks to a bugguide user for identification. Seems like there is a good chance she'll change color. My field guide with pictures (the same one that initially misled me on the caddisfly) suggested that it was a Goldenrod Crab Spider, but I was not feeling very confident in the guide, and did not want to base my ID on a general picture alone.*

Wednesday, December 23, 2009


Here is the first caddisfly, order Trichoptera, which I have managed to identify, only the second one I've collected. General consensus is that it is a northern caddisfly of family Limnephilidae. Their characteristics include ocelli, head and wings with silky hairs, tan forewings with long silver stripes. Like other caddisflies, they construct cylindrical tubes, sometimes called "log cabin cases," with long, dead leaf pieces and twig fragments. Caddisflies also use small pebbles, dirt, and man-made items - some rear caddisflies so they will make unique jewelery, while others imitate them to make fly fishing lures (caddisflies are apparently very delicious to fish, as are mayflies, dragonflies, etc.).

Trichoptera; Limnephilidae; Psychoglypha sp.
Common Name: Northern Caddisfly

It belongs to the genus Psychoglypha. It was found in North Lake Tahoe, Carnelian Bay, on a patch of snow at night. Per a source from bugguide, caddisfly adults can be found during the winter, and may be called "Snow Sedges" by northwestern fishermen. It is thought they emerge in the fall and overwinter as adults before laying eggs in the spring, often surviving through subzero temperatures.

Friday, December 11, 2009


Staphylinidae are rove beetles, which are slender, elongate beetles with very short elytra. The elytra give the insect almost a four-body-segment look, and resemble pincer-less earwigs. The hinds wings are well developed and at rest are folded under the short elytra. They are active insects that run or fly rapidly. They often raise the tip of the abdomen like a scorpion if they feel threatened and their mandibles are large enough that they can inflict a bite if handled. The largest reach 25mm in length, and most are black or brown. It is one of the two largest families of beetles - there are 4,153 species in North America. I would key it to genus, but the closest I can get is tribe - my volume of beetles unfortunately does not cover polyphaga...perhaps I will get the next volume for Christmas...

Coleoptera; Polyphaga; Staphylinoidea; Staphylinidae; Staphylininae; Staphylini; Ocypus sp.
Common Name: Large Rove Beetles

They were found at night, I only collected one. The other two I happened across during a night survey. The first one I ever found was by the beach, a lot of rove beetles can be found close to the shore. At any rate, there it is. Also, in one of the pictures, you can pretty clearly see the large mandibles. Three species of the genus include O. olens, O. nitens, and O. aeneocephalus, and the range of O. olens matches the location in which this specimen was found - so O. olens is the most likely candidate.

Thursday, December 3, 2009

Stenopelmatidae Part 2

After my disappointment that I couldn't find a live specimen for my first Stenopelmatidae post, I found one in my pool, extremely distended but perfectly preserved, and thought it a good opportunity to show off some insect anatomy. Below, I have an unlabeled photo and a labeled photo of the "face" of one of the Stenopelmatus species.

Stenopelmatus sp.

In case any of the labels are too hard to read, here they are listed, generally from top to bottom: Frons, Pedicel, Scape, Anterior Tentorial Pit, Frontoclypeal Suture, Clypeus, Abductor Tendon, Mandible, Labrum, Stripes, Postmentum, Prementum, Lacinia, Paraglossa, Hypopharynx, Galea, Maxillary Palp, Labial Palp. Now for a few other lovely pictures - In the ventral view, you can see the soft, unsclerotized endoskeleton that connects the sclerotized shield-like segments. This is necessary for insects, because if their whole exoskeleton were fused and sclerotized they would be unable to move.