A Round of ‘Colas (one wolf spider’s progeny)

On a mild day at work in early April, a spider appeared seemingly out of nowhere (as they usually do) in the cafeteria. I could tell it was a wolf spider (family Lycosidae) by its shape and characteristic eye pattern, but I wasn’t sure which kind. There are a whole bunch of wolf spiders in North America, well over 200 species. They come in all sizes, too. There are your big mama (and papa) Carolina wolf spiders (Hogna carolinensis) that would cover your palm all the way down to the smaller wolf spiders from the genus Pardosa that would be dwarfed by a bottle cap. Regardless of size, all wolf spiders have eight eyes with two, big “binocular” eyes facing forward, two kind of on top of the head, and four little ones that resemble a mustache. This is the typical wolf spider face. They are fairly robust spiders that actively hunt or sit and wait instead of building webs to capture prey. Another big giveaway is if you see a spider running along with an egg sac attached to its butt, it’s a wolf spider. And when that sac opens, all the spiderlings gather onto the mom’s back for a few weeks until they are ready to hunt on their own. Wolf spiders are the only spiders that do this.

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Wolf spider eye pattern. I believe this lady is in the Rabidosa genus.

My cafeteria wolf spider was a female about 9mm from face to spinnerets. She was quite pretty; light brown overall with a tan highlight down the middle of her head that ran halfway down her abdomen. There was no banding on the legs. The tan highlight on her abdomen (aka heartmark) was the standout for me. Most other wolf spider heartmarks are dark if they have one. Going by these visual markings and her size, I guessed she was Trochosa terricola after referring to Richard Bradley’s guide. I gathered info from other resources and learned that there is another similar species in the Trochosa genus, Trochosa ruricola, which can also be found in the eastern half of the US. Without the highly invasive procedure of putting her under the scope for a positive ID, I thought it safe to say Trochosa species. I nicknamed her “Cola”.

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Trochosa species, AKA “Cola”. Notice the light midline on the head has two darker stripes inside of it, a characteristic of the Trochosa genus. Also, these spiders have rather short legs.

I kept Cola in a 62oz. container with some moist dirt, bark, and moss. She liked to chill out in the nooks and crannies. About a week later, she started to except food. My initial attempt at offering her a small cricket ended with the cricket walking right over top of her twice. When I tried smaller quarry like flightless fruit flies, she caught them in the air like a dog and totally gobbled them. If a spider could gobble, she did that.

Later that month, a friend was at work and saw a spider crawling across the floor, seemingly out of nowhere. When I received the spider, I could tell, with my now trained eye, that the spider was a Trochosa, more specifically, one of the “Colas”. And to make it even more interesting, as you may have guessed from the title of this story, it was a MALE “cola”! He was a little smaller than the female and had dark hairs halfway down his front legs making it look like he was wearing black socks. Now, the questions were, are they the same species, are they both mature, and would they mate, or is someone going to be a meal?

I decided to introduce them, a little worried it could be a bad scene, but how would I ever know, right? I put the male into the female’s cage. The disturbance sent the female running and the both spiders followed the perimeter of the enclosure right into each other. At first, the female lunged at the male then they remained motionless facing one another about an inch apart. The male began to flutter and wave his front legs with those bold, black socks. Mate recognition! The female stayed still as the male approached her slowly with front legs waving and tapping on her front legs. She withdrew her legs the closer he came which seemed like a submissive action to his approach. This was going to happen! Finally, he positioned his body over hers and wrapped his legs around her in a bear hug. With her fangs safely beneath him, he inserted one palp around and underneath the females abdomen and then switched with his other palp on the other side. If you want to know more about how spiders mate go ahead and read the The Birds and the Boxing Gloves?. He would occasionally wag his abdomen during the process, which was interesting. After each alternation, he’d run his palp through his fangs almost as if cleaning it. When all was over, they parted ways quickly running in opposite directions. I removed the male back into his enclosure. The entire process lasted less than 10 minutes.

Mating Trochosas!

A few days later, Cola’s abdomen was swollen and she had a voracious appetite aggressively attacking a cricket nearly twice her size! Later that week, my friend caught another male Trochosa at work. I decided to see what would happen if I introduced them. Would they mate? They initially ran from each other. The male did some front leg movement but the female actively avoided him, uninterested in mating or dining. I removed the male and released him. Sorry, bud!

Exactly ten days after the mating, I noticed a small, silky hump in the substrate of Cola’s enclosure and she was nowhere to be found. The hump was about a square inch and resembled a tent decorated with debris. Cola was inside. I could see her silhouette when I angled the enclosure by a light.

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Silk tent

I had never observed a wolf spider in a silk tent with her egg sac. They were usually travelling out in the great wild with it attached to their spinnerets. I continued to check on her waiting and wondering. Was she alive in there or what? The male was hunting and doing fine in his separate spider bachelor pad. Days and WEEKS went by! Finally, Cola emerged, her abdomen covered in tiny little spiderlings! She had stayed in the tent with her egg sac the entire time!

 

Eventually, the tiny spiderlings dispersed throughout the enclosure. I kept ten and released the rest except for one tenacious baby who was the sole passenger on mom’s abdomen. Even after Cola grappled a large cricket and rolled onto her back, the spiderling clung fast! There’s always one slow to leave the nest!

Some time in mid June, the dad spider died, but not without having done his biological duty, and THEN some, because the very next day, Cola had made another silk tent! Later that summer, in July, Cola produced a third egg sac. This one was much smaller than the last two and she didn’t hide inside her silk tent as long.

The time came to release Cola, the rest of her babies, and the lone remaining spiderling that had survived from her first sac. Nine out of ten had died in mid-molt or mysteriously. Now the spiders would have to deal with an additional challenge: predation. Thinking about life cycles, I felt lucky that I was able to observe the mating process of two spiders, caught in different locations, that had survived and/or possibly escaped, wasps, birds, people, a bad molt, and desiccation to go on and make more of themselves. Cheers to a round of ‘Colas!

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