Awesome Arachnids

She asks me to kill the spider.
Instead, I get the most
peaceful weapons I can find.

I take a cup and a napkin.
I catch the spider, put it outside
and allow it to walk away.

If I am ever caught in the wrong place
at the wrong time, just being alive
and not bothering anyone,

I hope I am greeted
with the same kind
of mercy.

~Rudy Francisco

I led a full moon walk this past week at Mason Farm Biological Reserve, a wild and wonderful tract managed by the NC Botanical Garden, only a mile or so from my office. I love being outside at night, hearing the night sounds, and trying to catch a glimpse of the creatures that make darkness their time of choice. The night before the hike, I walked alone along the trail at Mason Farm, looking for things to highlight and reacquainting myself with the brilliance of an almost full moon. A variety of night sounds greeted me as I walked in silence – the startling snorts of alarmed deer, a solitary hooting of a Barred Owl, a lone tree cricket…but the most magical was when a group of Coyotes initiated their yipping and howling as the moon rose above the tree line. Though it lasted less than a minute, it is a sound that sticks with you (and might even raise the hairs on the back of your neck a bit). Chilly night temperatures, combined with recent floods, seemed to reduce the number of night-time invertebrates that were out and about.

Ther Laugher Moth larva on oak

A fuzzy larva of The Laugher Moth feeding on oak, my only glow-in-the-dark caterpillar this past week (click photos to enlarge)

I searched with my ultraviolet flashlight for caterpillars, hoping to find some of my favorite slug larvae species, but came up with only two fuzzy larvae of The Laugher Moth. But there was one group well represented and quite noticeable, if you know how to look…

Carolina wolf spider 1

Carolina Wolf Spider, Hogna carolinensis, out and about along the edge of a field

Yes, that’s right, and somehow theme-appropriate at this time of year, spiders! On my pre-trip, they were everywhere, especially concentrated along the habitat edges (boundary between forest and field) and along the stream banks and swamp edge. If you don’t know, you can “sniff” spiders by holding a flashlight near your eyes or nose (or wear a headlamp) and scanning your surroundings. On almost any night from March through October, you are likely to see what look like dewdrops scattered across the ground. These are most likely spider eyes reflecting your light back to you (some may be dew drops if it is damp). If you are just holding a light down by your side, their reflection comes back at that level and you probably can’t see it. That’s where the sniffing part comes in. You tell your group you smell a spider. Since most people don’t usually walk around with their flashlight up near their eyes, they can’t see the eyeshine. On my program walk, I was able to run about 25 feet over to a tiny spider on a tree trunk by keeping my light on it to see its eyeshine. Of course, you always share that trick with your participants so they can see for themselves the incredible abundance of these spiders.

Hunting spiders, like wolf spiders, have a reflective layer in their eyes that bounces the light around so that there is a better chance to have it absorbed by the rod cells that help them see in low light. This is similar to what happens in the eyes of nocturnal vertebrates like deer and cats. One of the larger species out this time of year is the Carolina Wolf Spider which generally hides in underground burrows during the day, and then emerges to hunt prey at night. Females carry their egg sac off the tip of their abdomen. The baby spiders hatch and ride on the mother’s back for a week or so until they molt and then disperse.

Rabid wolf spider

A large, female Rabid Wolf Spider, Rapidosa rapida

Another large, and quite common, ground hunting spider is the oddly-named Rabid Wolf Spider. Its common and scientific names come from its rapid movements, not any ability to carry a mammalian disease. The bold stripes on the cephalothorax (the front body part that is sort of a head and thorax combined) are diagnostic of this species (along with some more subtle features). Males are distinguished by their smaller size and by the first pair of legs being black.

marbled orb weaver

A Marbled Orb Weaver, Araneus marmoreus, in her web

There are relatively few web builders left out in the fields and woods this late in the season, but there is one notable exception, the Marbled Orb Weaver. This distinctively colored (yellow or orange abdomen) spider can be found in woods and along field edges into November. During the day, the large female hides in a folded leaf retreat along the edge of her circular web. She holds a line of silk attached to the web to detect and struggling prey. At night, they are more typically found perched in the center of the web. Their color scheme and occurrence through late October has given them another common name, the Halloween Spider. Web-builders typically have no eyeshine since they rely less on vision and more on vibrations of struggling prey in their web to obtain their meals.

Dolomedes spider

A huge Dark Fishing Spider, Dolomedes tenebrosus, on a tree trunk at the edge of the swamp

The best spider find on our tour was made by one of the participants as we stood near the closed portion of the trail through the swamp. Hurricane Florence took out the boardwalk through this section so you can no longer walk the circular route. But, perhaps because of that pause, we got to see one of our most spectacular spiders, a very large Dark Fishing Spider. This large female would almost fill my palm. They are frequently found head-down on tree trunks (like this one) near water, but can occur quite some distance away. I have them in my workshop and frequently find their sheds scattered among my scrap wood or tools. There are other members of this genus that are more frequently found on and/or in water (e.g. the Six-spotted Fishing Spider) where they actively hunt for creatures that fall on the surface, or those that live just beneath (like aquatic invertebrates, tadpoles and even small fish). Female fishing spiders carry their egg sac beneath them, hanging onto the silken bag with their chelicera. When the young hatch, she creates a nursery web for them where they stay for a short while before dispersing.

bread

Even the bread, Greatbreadus multigrainiia, at the Farmer’s Market is arachnid appreciative

I had a chance to write up some of this on Saturday, but not before I made my weekly trip to the Carrboro Farmer’s Market. There, I spied one more thing to add to this post – a loaf of beautiful bread from Chicken Bridge Bakery. So, whether its a graphic on tasty bread or an eight-legged critter on the trail, take the time to learn more about these awesome arachnids. If you want to learn more and see some incredible photos, check out some of the scientists I follow on Twitter – TurnFear2Fascination, Catherine Scott, and Thomas Shahan…you, too, will learn to appreciate these amazing creatures even more. Happy Arachtober!

14 thoughts on “Awesome Arachnids

  1. Thanks for another great article, Mike! Those wolf spiders are a fearsome looking bunch! Needless to say, I’ve seen many similar spider living just down the road from you. My reading says that they may actually bite but the bite, while somewhat painful, is not poisonous. But I also read that most of what we see (at least during the day) around here are not wold spiders, but are a similar looking and similar sized spider that I can’t remember the name of. Is that you understanding also (all of the above in question)? Would appreciate your comments. Rich

    • Hey Rich…you are correct re bites of these large wolf spiders – highly unlikely to be bitten, but supposedly painful if you should squeeze one and get bit. All spiders have venom, but most are not severe on humans. Re spider ID, there are many species of wolf spiders out and about along with some similar-looking members of the grass spider group, but the la=tter build sheet webs. Wolf spiders are free-roaming hunters.

  2. Interesting article in the New York Times science section today with some fascinating spider videos, including the mating behavior of fishing spiders mention in your blog. Just thought you might enjoy it!

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