Or: The most exciting part of the conference (for me) was getting there!
I’ve been chasing Pardosa wolf spiders from one corner of Texas to another all year. One species I hadn’t encountered was Pardosalittoralis, which I eventually learned was only found in brackish marshland. I had wanted to check out the Texas coast for wolf spiders for sometime, and the TMN convention gave me an excellent excuse.
So, I drove to Houston via Surfside and Galveston. No one on iNat had encountered Pardosalittoralis south of New York, let alone Texas. They’d been observed in New Hampshire and Nova Scotia at the opposite end of their range. I happily found some in small areas at several locations without a muddy mishap.
I wonder when the last human paid them any attention? Someone must have once, because they were known to be in Texas. Bonus: I’m now comfortable identifying these in Texas, something I couldn’t do before, since I never saw one in person or even in a photo, only those in observations made 2,000 miles away.
Male (left) and female (right) images attached. Body length about 2/10ths of an inch, male (black) slightly smaller than female.
Sometimes people ask me how long wolf spiders live, and that’s a question I have too. I’ve been looking and lately spotlighting for spiders on my property for a while, and suddenly I can’t find any Schizocosa avida day or night. I know another observer on iNat about 150 miles to the northwest who hasn’t seen any recently either.
Checking the months of my observations, I find a peak in March and few from August to December. They have to be there, but are probably too small to be noticed. So, I have one answer: they live about 14 months and are mature for the last few.
Observations for their entire range on iNat show a similar pattern. On the other hand, adults of some Pardosa are present and breeding year round, so figuring out how long they live is a lot harder and could be less than a year. I suspect Hogna antelucana live well into their second year at least. So, it’s complicated.
I didn’t have my usual spider accessories when I encountered this spider indoors, and the only thing I could find to use was a small glass jar. After getting the spider to run into the jar and taking it outside, I took some ventral photos followed by some dorsal photos after I released it. The lighting was harsh, but the images were adequate for identification. At the time I thought it was one of the darker Tigrosa species because I knew it was something I hadn’t seen and was expecting to eventually find some in Gause. Tigrosa is a common genus, but I’m not very familiar with it because I rarely encounter it. I soon found out my ID was wrong but didn’t feel too bad since the most recent Tigrosa helluo observed at iNat looked just like mine. After looking at all the Tigrosa options, I found that all had a narrow carapace pale medial band, which ruled mine out. I thought it might be Trochosa, but the medial band wasn’t as strong between the posterior eyes as those I’d seen before. I checked Varacosa before returning to Trochosa. Looking at the Trochosa sepulchralis observations, about a quarter looked just like mine.
So how does my observation fit into the iNaturalist world? There are 78 observations of the species of which 48 are in Texas showing how much we love our wolf spiders. The range of Trochosa sepulchralis covers most of the US east of the Rockies except for the extreme northern parts.
There are probably significantly more observations at iNat that are unidentified or misidentified. I know for sure there is at least one under Tigrosa helluo. This was my first Trochosa and the first Trochosa sepulchralis observation for Milam County. Note that my ID hasn’t been seconded yet, but I’m pretty sure I’m right.
Wolf spiders are too hard for amateurs to identify
I’ve heard that, and you may already believe it even though there is at least one species, Rabidosa rabida, that most people are familiar with. On bad days I even believe it. Wolf spiders come in many kinds and sizes, and their rapid movements out in the open often bring them to our attention. Rabidosa rabida appears to seek out commotions in daylight, and we’ve all been surprised by seeing a big one standing motionless nearby when we’ve been busy doing something. There’s a game I play. I set foot on a property and say, “Now where are the wolf spiders?” With a little practice, you can be a regular winner. So, people are constantly reminded that they can’t put a name to those dang wolf spiders.
The life cycle of a wolf spider is simple compared to a butterfly. There are eggs, spiderlings clinging to their mother, and then spiders which get bigger and bigger and almost unnoticeably change from juvenile to adult, and then they grow some more. Since they have exoskeletons they have to moult repeatedly as they grow. During each molt they have the ability to make physiological changes including re-growing lost legs. None of the changes are as dramatic as a chrysalis turning into a butterfly, but many subtle changes can occur during each molt. It’s that long period of gradual development that causes most of the identification difficulties. I figure you’d need at least five separate identification guides to cover Hogna antelucana at various times during its growth. Because I rarely encounter older spiders, I was unaware of a later change in Hogna antelucana when I did the presentation back in July. Thanks to seeing other people’s observations come in during July and August I’m aware of it now, and an addendum will be forthcoming. Think of the difficulty of writing a guide on wolf spiders. Each species would take a half dozen pages and be too complicated to make sense of unless very carefully presented. And what about regional and seasonal differences?
I don’t want to scare anyone away from trying to identify wolf spiders. The truth is, if you take photos of multiple spiders in one place at one time you’ll find many as alike as peas in a pod. Given the same history, the appearance of spiders is remarkably similar. Get to know a population and watch it for a year and then you will be able to identify the next individual on sight regardless of their age or sex. Going to a new place and encountering the spiders there the first time is a greater challenge, but it may turn out there is less regional variation than people thought after developmental changes are taken into consideration. In the long run we’ll work out which characteristics are most reliable for identifying each species. Having iNaturalist and BugGuide is a great asset. I was able to virtually travel 4,000 miles looking for a particular species group along the way in less than a week and without leaving my house. Nevertheless, I still prefer to interact with them in real life.
The main image of the observation below was taken on Mustang Creek under the U.S. 79 bridge southeast of Taylor. I was specifically looking for it there and found just one. After the photo session she was released right where I found her and is probably covered in spiderlings as I write this. I’m trying to locate all accessible populations of these in eastern Williamson and Milam Counties. At this point I found them in three locations, plus a single individual roaming downtown Taylor a half mile from where it should have been. That’s all I could find until water levels in the creeks and rivers drop. They like rocky or pebbly areas with water on one side and low vegetation on the other. If anyone has an accessible area like that on their property, I’d appreciate a chance to visit.
When we learned about scientific names in the training classes, we were introduced to how the name of the person that initially described them is often appended to the name. At the time, it seemed rather redundant.
As I found out recently, it can be very useful. I’ve been trying to untangle the lapidicina group of Pardosa wolf Spiders in Texas. These are the largest of the Pardosa spiders around here, and they like rocks, especially limestone outcrops. Their common name is stone spiders because of it.
I’m not aware of any in Milam County, but there are some at Granger Lake just next door. There are also some along Brushy Creek in Williamson County and several places along the lake near Belton in Bell County. In total, there are four species in Texas, which are apparently found in limited areas that don’t necessarily overlap.
Here’s what happened. P. sierra was described by Banks in 1898 from specimens collected in Baja California. P. atromedia (California) and sura were described subsequently. In 1959, Barnes decided they were all the same species, P. sierra, which had an immense range in southwestern U.S. and in Mexico. This was based on similar morphology of genitalia.
Then, in 2010, Correa-Ramirez et al. looked at the genetic code of specimens and concluded that they were indeed separate species, and that atromedia was in California, sierra was in Baja California, and sura was everywhere else. Additional studies may eventually add to these ranges, but for us it’s very likely that Texas has sura and not sierra. The other species in Texas are lapidicina, mercurialis, and vadosa. They are difficult to tell apart and all appear to come in a variety of colors and patterns.