Sunday, March 9, 2014

Ground Spiders, Sergiolus

Few spiders are as colorful as those in the genus Sergiolus. Why they are so boldly marked is something of a mystery, though there is suspicion that they may be mimicking velvet ants, wingless wasps in the family Mutillidae that pack a potent sting. Sixteen species of Sergiolus are known north of Mexico.

Sergiolus sp. male from Indiana

These nomadic arachnids are very agile, at least when fleeing potential danger, and they often prowl through leaf litter, so you may only get a glimpse of one. Be patient, though, and it is likely to reappear. They are also good climbers, so don’t be surprised to find them on foliage, or walls, too.

Sergiolus are medium-sized members of the family Gnaphosidae, females ranging from 6-10 millimeters in body length, males 5.5 to 7 millimeters. They are mostly diurnal (day-active), so are even more conspicuous than the average spider. The obvious, cylindrical spinnerets at the tip of the abdomen are characteristic of all Gnaphosidae, but helps distinguish Sergiolus from colorful spiders in other families. There are other ornate gnaphosids, such as Callilepis, and separating the different genera hinges on subtle distinctions in the genitalia (epigynum of females, pedipalps of males).

Male Sergiolus sp. from Colorado

Since there are several species, I am reluctant to assign specific names to the images shown here. One of the more abundant species found from the Nebraska and Oklahoma eastward is S. capulatus, sometimes known as the Variegated Spider. It bears an uncanny resemblance to velvet ants in the genus Timulla, which frequent similar habitats: sun-dappled patches on the floor of deciduous forests. The spider is also found in gardens, meadows, even lawns.

Female Timulla sp. velvet ant

One common western species is S. montanus.

While Sergiolus does not spin webs to snare prey, they do construct retreats in which to molt, guard an egg sac in the case of females, and perhaps to overwinter. They probably live over a year, as adults can be found in almost any season. Obviously, they are most active during the warmer months.

Look for these and other spiders, as well as insects, in sunlit spots in wooded areas. You will be surprised at what shows up if you simply sit and watch. Sergiolus can also be found under stones and other objects in reasonably dry situations.

Male Sergiolus capulatus? from Indiana

You can keep gnaphosids in captivity with relative ease. Almost any container will do. Provide them with water, as they do not obtain water from prey. I furnish a small wad of cotton soaked in water at least once per week. A small insect can be fed to a spider every other week or so. Spiders are built to withstand surprisingly long periods without food. Remove the prey insect if it has not been consumed within two days. Spiders preparing to molt will not feed and are therefore vulnerable themselves to predation.

Note: Several members of the genus Sergiolus were once placed in the genus Poecilochroa, and older references treat them as such.

Sergiolus montanus? from Colorado

Sources: Bradley, Richard L. 2013. Common Spiders of North America. Berkeley: University of California Press. 271 pp.
Kaston, B.J. 1978. How to Know the Spiders (Third Edition). Dubuque, IA: Wm. C. Brown Company Publishers. 272 pp.
Ubick, D., P. Paquin, P.E. Cushing, and V. Roth (eds). 2003. Spiders of North America: an identification manual. American Arachnological Society. 377 pp.


  1. I Found a sergiolus capulatus in Muskegon Michigan yesterday on my wall inside. I captured it. And am letting it go outside. It is a neat looking spider.

  2. I have pictures of it also. Still have it in a specimen cup. Had to identify it to make sure it wasn’t poisonous if you’d like to email me, I’ll send you the pictures. I seen on one website that their was only 13 states with sightings. Not sure how accurate that was. But Michigan was not one of the 13 states.

  3. Just found one in Virginia on my carpet. I thought it was an ant at first, but then I noticed 8 legs lol. Put the bugger back outside.

  4. I am in western North Carolina and I was cleaning out a truck tool box and found this little guy. I have never seen a spider that looks like this before so I had to look it up. Surprisingly, no one has reported one in this area before.

  5. Just found one on our wall in Virginia. Beautiful, but now I don’t know where it went!

  6. Just discovered one in my bedroom in PA. Took it outside, but had to look it up - never have I seen a spider so unusual looking.

    I also think its interesting that all these comments are from the past month, even though the blog was written 6 years ago. I wonder if this species is having a banner year.

  7. From Tennessee here! Just found one of these guys in my hallway. Like Sarah said interesting so many sightings close together!

  8. Found one in my office today, never seen one before. I am just outside NYC.

  9. Just found one in our bathroom. Cute little gal (I think). Missing one leg, sadly. We live near Downtown Salt Lake City, Utah

    I put her in our potted plants, as I could not find any danger risk to having her around.

  10. Found one in my apartment today in Atlanta, GA area.

  11. Just found one in my bedroom in North Idaho!! Glad we found the little (BIG) creeper BEFORE going to sleep! LOL. ;)

  12. Was running across the floor - looks really cool!

  13. I found one on my bed today in Western Washington. Scared the dickens out of my son. I'm actually rather surprised he was in my room as we have 51 tarantulas in here. He is adorable so I may give him a home.

  14. I just found one in Eastern Washington today. Poor little thing was just trying to catch a winter nap in a nice little webby sleeping bag that got stuck to my hand when I was moving some stuff around outside.
    Scared the hell out of me when it emerged sleepily from the sac that was still attached to my skin!
    After flinging it loose in a panic I scooped the poor cold and tired little guy up from the snow and brought it in to warm up. Considering keeping it cozy warm and fed for the winter to make up for the shakeup.

  15. Found one kelowna B.C 04/13/2021