Wolf Spiders Are too Hard for Amateurs to Identify

by Eric Neubauer

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?

Wolf spider with spiderlings. Photo by SA Kendall.

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.

Pardosa mercurialis with egg sac

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.

Another view.

Scientific Names for Spiders Are Handy

by Eric Neubauer

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 one found near Granger Lake. It’s looking right at us!

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.

Wolf Spider Identification

by Eric Neubauer

Although some wolf spiders are active year round, this is the time of year when they start to become more noticeable. Except for a few species that are relatively easy  to identify on sight, these can be very difficult to get down to species level. There are two main reasons. First, there a lot of genera and a lot more species. You are most likely to see are Rabidosa, Schizocosa, Pardosa, Hogna, and Tigrosa in our area which isn’t too overwhelming. However, the second and third of these include over two dozen species locally. The second reason is that most keys rely on microscopic details. There are macroscopic differences, but these haven’t been compiled in any comprehensive way. It may be some time before wolf spiders become as easy to identify as birds or butterflies, but I believe it will happen.

Unidentified juvenile Hogna. More on this one below.

Where to find them: wolf spiders live in diverse habitats. Margins of mowed areas, shorelines, road edges, and leaf litter are good places to look. They are noticeable because they run around in the open looking for prey. They they like to be where there is a way to escape whether it’s into tall grass, under leaves or onto the water’s surface. Many live in colonies, so if you find one, you can probably find more. I find the best time to look is when the temperature is above 70 and humidity is high. On sunny calm days, you can find them active at lower temperatures because the ground warms before the air. And, they aren’t always large. There are some species that have a body length of 0.15” or 4 mm when mature. Males tend to be smaller and a bit more lively than females, and they are harder to catch. As far as I know, none of the local wolf spiders have a dangerous bite, and they won’t bite without a lot of  provocation.

Rabid wolf spider Rabidosa rabida in a clear container

How to photograph them: good photos are important if you hope to make a species ID. Wolf spiders can usually be encouraged to run into an open container. Wolf spiders can jump, but do so more in a horizontal than vertical direction. They can climb, but not as well as other spiders. They will remain in the container until you get some good photos. Size is important, so if the bottom of the container has markings, you use them to scale the body length. Ventral views are important too. Looking up though the bottom of a clear container works. Others put the spider in a plastic bag so it can be flipped over. I try to release spiders close to where I found them when I’m finished with them. If you do all this, you might just have the clue that points to the species.

Unidentified Hogna, from the bottom (Hogna incognita)

Study populations, not individuals: Once you find a colony of spiders, visit it often and make a full collection of photos including males, females, females with egg sacs, females covered with spiderlings, and juveniles. Most experts wouldn’t dare identify a juvenile from a photograph at present. They do look a little different than the adults. However, from my experience working with two species, the juveniles are not only distinctive, but are more consistently patterned than the adults which will have developed some individual “character” in their appearance. In the future, the juveniles may provide the necessary clue for the species of an entire colony.

Thin legged wolf spider, genus Pardosa, with egg sac

Legs: I’ve noticed wolf spiders missing legs. Usually it’s one or two, but I have seen as many as four missing. Males are more likely to be missing legs than females. Legs can regrow, so you may notice a leg that doesn’t look like the others.

Pardosa male missing two legs, with a third that doesn’t look too good.

Recent Observation Notes from Bird and Bee Farm Trip

I continue to be surprised how finely placed the populations of wolf spiders are. At the pond dam, I found a couple of juveniles near the highest point. The first was one of my Hogna incognita (undescribed species). The other was Rabidosa rabida which seems to be species that appears everywhere in small numbers rather than being clustered in populations except perhaps around buildings. I found no more spiders until I got to the boat ramp at the far end of the dam. That’s where all the Pardosa were. The Pardosa may be all one species which would be good since most places I see them there appear to be multiple species that I haven’t been able to sort out.

I stopped at the Little River bridge north of Gause and found no spiders there. Then, I checked out the San Gabriel bridge on CR 487 east of Crossroads, which has an inspection road around and under the bridge. A bunch of spiders were in a pile of leaves that someone had dumped. I’d thought they were Pardosa at the time, but a closer look at the photos suggest Schizocosa juveniles. So, I found all four of the most prevalent genera in Milam County on my tour.

The H. incognita find was of interest. Although it seems to be mostly a Blackland species, this personally confirms it is present elsewhere, which I already figured would be true from other people’s observations. Nevertheless, its range may stop abruptly at the Brazos River. I’ll be testing that out in the next few months when they are active.

Here are some more wolf spiders to practice on. All photos by Eric Neubauer.

Horned Owl Sighting and Spider Discovery

by Eric Neubauer

Saturday, January 16:

6 AM: I currently have two Horned Owls calling at the same time from approximately the same nearby place. Typically, one starts and the second, with a slightly higher pitch, starts about a third of the way through so that the notes alternate. And, they’re still going on. This has been for at least 12 minutes.

Sunday, January 17:

Again, there was one on the power line in front of my other neighbor’s house at dusk. I watched him fly down to the ground, then up to the top of the fence, then up to the power line in front of my house. As it got too dark to see, it flew toward the back of my property and disappeared.

When interests intersect:

On Friday, I walked down to Alligator Creek for the first time in a while. On the way back, I walked slowly up the ditch looking for anything that moved. In a few places I found some tiny spiders.

I decided to go back today with a container to scoop up some the spiders for better photos. I looked carefully for about 50 feet without seeing any. Now where did I see those spiders the day before? Finally I saw one, looked around, and then it hit me: all I needed to do was follow the food chain to find the spiders.

Here were some small Texas Bluebonnet plants and other forbs, grasshopper nymphs, and tiny spiders. They were steps in the same food chain all gathered together for my convenience. On the Texas Blackland Prairie, grasshoppers and spiders seem to be the predominant arthropods. Take away the mixed vegetation of the prairie and there would be no grasshoppers, take away the grasshoppers and there would be no spiders. Take away the spiders and there would be no spider wasps, etc. I had noticed last year that the spiders’ gathering places shifted from week to week. No doubt they follow their food. Doh!

One of the Alligator Creek Spiders, identified as Dotted Wolf Spider Rabidosa punctulata by its location and subtle differences from the Rabid Wolf Spider.

Commonsense, but it took me a while to learn and understand. By the way, the spiders appeared to be a new Lycosidae species for me.

Here’s a rabid wolf spider Rabidosa rabida Eric found in another location.

And here’s his best photo of a dotted wolf spider.

Compare and contrast.

Wolf Spider Mystery

by Eric Neubauer

I’ve been watching a large population of Hogna wolf spiders growing up on my property since winter. I’ve submitted photographs to both iNaturalist and BugGuide, and people there don’t hesitate to confirm them all as Hogna antelucana.

Specimen of hogna wolf spider with the vee shape pinched shut.

Nevertheless, I found I can easily sort them into two groups from a fairly young age on. The markings on this species are quite variable in general, but one reliable difference between the two groups is in a lightly colored vee shape near the back of the head. The vee points toward the back and is open at about a 35 degree angle on one type and is pinched shut on the other.

Specimen with an open vee shape.

There are other small differences, but they are harder to define and less consistent.

At first I thought it might be a case of sexual dimmorphism, but lately I think there may be two different species.

The dark one.

The third example has the open vee, hard to see because the spider is looking up, and is very dark with none of the warmer tones these spiders usually have. It is the only one like that I’ve seen and perhaps lacks the ability to produce an orangish pigment.

It is one of several mysteries to keeping life interesting.