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Kelly’s Field Notes
Common Name: Wolf Spider
Order: Araneae
Family: Lycosidae (from Greek lykos meaning wolf).
Genera: There are currently 120 genera of wolf spiders! There are around 2400 described species as of 2023.
Species of Note Near You:
Carolina wolf spider (Hogna carolinensis) - the largest wolf spider in North America, this might be Kelly’s favorite because she worked with them for her Master’s Degree. She had a thicc female named Olga. Females have body lengths between 2 - 4 cm (0.8 in - 1.6 in) and leg spans of up to 10 cm (4 in).
Spotted wolf spider (Pardosa amentata) - common throughout northwestern and central Europe, as well as the British isles. You can’t miss their beautiful white spots! These are on the smaller side, with female body length up to 0.8 cm (0.3 in).
Tiger Wolf Spider (Hoggicosa castanea) - found throughout Australia, these hefty ladies have a body length of about 3.5 cm (1.4 in) and a leg span of up to 9 cm (3.5 in).
Wolf spider (Pardosa astrigera) - Found in Japan, China, Taiwan and Russian, females have a body length of about 1 cm (0.4 in).
Description:
Wolf spiders are hairy, long-legged spiders, usually black, brown, tan, or gray and often striped. They do not spin webs to catch prey, they are active hunters though some are ambush predators. They can be a variety of sizes! Some are less than 0.1 cm in body length (0.04 in) and others up to 3.8 cm in length (1.5 in). They have an easy to recognize eye pattern, which you can use to identify many families of spiders. Eight eyes total, arranged in three rows. Two large lenses front facing with four smaller lensed eyes in a half moon pattern below them. There are also two medium sized lensed eyes on top of the cephalothorax (head). Most spiders have pretty poor eyesight, but active hunters like wolfies, huntsmen, and jumping spiders, have excellent eyesight! Our wolfies have the third best eyesight of any spider family, with jumpers at number one and huntsmen number two.
You might notice their beautiful eyeshine at night, as they are nocturnal hunters. The tapetum lucidum, reflective tissue in the eyes, catches and reflects back any light helping them to see better in the dark. Surprisingly, it is not located in those big eyes in the second row, but only the third row of four smaller eyes.
Life Cycle:
Wolf spiders start their lives in a big egg sac with 100 or more of their siblings, attached to their mother’s spinnerets. One study mentioned Rabid wolf spiders (Rabidosa rabida) (not actually capable of carrying rabies) had 1,035 eggs in one sac. The mother-to-be spins fine webbing in circular mat shape, like a bird’s nest. She then deposits her eggs, covers them, and begins to manipulate the covered eggs with her legs, palpi (small front limbs) and chelicerae (mouthparts) until it is spherical. Then she attaches it to her spinnerets and she’s ready to go. This entire process can take up to 3 or more hours. Females can construct multiple egg sacs within their lifetime, from one to six, with smaller species being more prolific in number of egg sacs.
They will also mend any tears in the eggs sac. In one study, when an egg sac was removed from a mother and returned cut up and damaged, she tried to re-wrap it unsuccessfully. The mother then created a web sheet over the eggs and waited over them until they hatched. Other studies have shown that some species will carry the egg sacs of other mothers if presented with them; their maternal instinct is so strong.
She continues to actively hunt even with the sac attached to her. She is careful to keep it from dragging in the ground and makes sure it gets plenty of sunlight during the day, to enhance incubation. It takes between two weeks to a few months for the eggs to hatch, with help from mom. She gently punctures the egg sac with her chelicerae (mouthparts) and within about three hours all of her spiderlings are out. Once they are freed from the egg sac she slings webbing over her abdomen and the babies climb aboard. Sometimes there are so many the mother needs to brush them away from her eyes. One study demonstrated mothers will also accept foster spiderlings, allowing them to crawl up their backs either with her spiderlings or if she is waiting for her own sac to hatch. Unmated females are less enthusiastic about this but also eventually accept foster young.
Here they hitch a ride with mom for a few days or weeks, depending on species. They do not need to eat during this time, living off of their fat reserves from the egg, but they do drink. The mother will gingerly dip her legs into a water source and the young will climb down to drink. After a few days to weeks, the spiderlings create a strand of webbing and balloon away on the breeze. Because wolf spiders are cannibals they need to separate as much as possible. Mothers will also eat spiderlings but some will not for up to two weeks after their own have dispersed. Some species go through 8 instars before becoming adults. For example, it took an average of 30 days for completion of each instar of Pardosa sierra. Wolf spiders live in total for between 1 and 3 years.
Super Powers:
Speed - wolf spiders can run up to two feet per second!
Pouncing - like their namesake, wolf spiders pounce on their preys.
Eyesight - they have the third best eyesight of any spider family.
Camouflage - it is difficult to see a wolf spider unless they are moving, they blend in very well to their environments.
Venom - while wolfies produce venom, they are generally harmless to humans - causing itching, swelling, and mild pain.
Music - male wolf spiders can rub their pedipalps together to create a vibration. They do this on dried leaves so females will feel the vibration and pick it up. Bonus! Humans can hear the leaf vibrating as well.
Holding Their Breath (sort of) - The yellow-striped bear spider (Arctosa fulvolineata) can remain underwater for up to 40 hours! They essentially put themselves into a coma, which helps them survive flooding.
Mentioned in this episode:
References:
Eason, Ruth Robinson. "Maternal care as exhibited by wolf spiders." Journal of the Arkansas Academy of Science 18.1 (1964): 13-19.
Pétillon, Julien, William Montaigne, and David Renault. "Hypoxic coma as a strategy to survive inundation in a salt-marsh inhabiting spider." Biology letters 5.4 (2009): 442-445.
Planas, Enric, Carmen Fernandez-Montraveta, and Carles Ribera. "Molecular systematics of the wolf spider genus Lycosa (Araneae: Lycosidae) in the Western Mediterranean Basin." Molecular phylogenetics and evolution 67.2 (2013): 414-428.
Punzo, F., & Farmer, C. (2006). Life history and ecology of the wolf spider Pardosa sierra Banks (Araneae: Lycosidae) in southeastern Arizona. The Southwestern Naturalist, 51(3), 310-319.
Thompson, Helen. “Listen to the Dulcet Purr of a Wolf Spider.” Smithsonian Magazine, www.smithsonianmag.com/smart-news/listen-dulcet-purr-wolf-spider-180955482/. Accessed 3 Nov. 2023.
Wagner, James D. "Egg sac inhibits filial cannibalism in the wolf spider, Schizocosa ocreata." Animal Behaviour 50.2 (1995): 555-557.
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