By way of Master Gardener Help Desk Coordinator Linda Esser’s neighbor, Brian Powers, we don’t have a “bug” insect this month, but a super-cool Arachnid. Mr. Powers sent photos to Linda of this spider and, with help from MG Kathy Nelson and confirmation by VT Entomologist Eric Day, it was identified as a Trapdoor Spider.
Here is a quiz for you – – – look at the picture. Although it is known that spiders have eight legs, I want you to count them and see what you think. If you did, you’re right – – if you counted and came up with ten legs. But, wait – – spiders are only supposed to have eight legs, so what gives?
Do we have a photo op? Maybe a mutant sci-fi spider? No, this spider has eight legs that are thick and short, and two fangs that look like an extra pair of legs, plus two body parts – an abdomen and a thorax. These leg-like fangs move in a stabbing motion, are sharp and can leave puncture wounds; however, their venom is low-level (non-toxic) to humans. When first disturbed, the spider can appear aggressive, standing up and presenting its fangs, but in general, the Trapdoor is a calm spider.
Trapdoor Spiders average 2.5 cm (~1 inch) in length but can reach up to 4 cm. They are thinly covered in hairs and have eight eyes (a pair in the middle with three located on each side). Their colors range from yellowish brown to reddish brown to black. In the U. audouini species, the abdomen is dull black with shiny dark reddish-brown to blackish legs and carapace (hardened shield over the thorax).
The example found by Mr. Powers (above right) was most likely a mature male searching for a mate. Males wander during warm humid weather (July- August) in search of a female’s burrow. Mating takes place in the female’s boudoir. The male usually escapes (before being considered “dinner”) to live another day and mate with several females before dying.
Females may lay their eggs several months after mating and protect the eggs within their burrow. The young spiderlings, upon hatching, may remain for several months before dispersing from the burrow to make their own burrows. Some species may disperse aerially by ballooning on silken threads.
The Trapdoor Spider spends most of its time underground in its burrow. The burrows are usually only 5”-8” deep, silk-lined, and the entrance is capped with about a 1-inch cork-like hinged lid (photo at left). Hinged by silk on one side, the spider holds the lid door partially open at night (spiders are nocturnal) in hopes an unexpected meal might wander by. They will put out trip wires to aid in detecting the vibration from an unsuspecting meal. This “trap door” is camouflaged with soil and plant debris. Held ajar, the spider ambushes its prey by leaping from the burrow and implanting its fangs into its victim. Their prey consists of insects, other arthropods, even frogs, mice, baby birds, baby snakes and small fish (depending on the species). Therefore, like all spiders, Trapdoors are considered GOOD GUYS.
Trapdoor Spiders are often kept as pets, but should be kept by experienced individuals only. The spiders are related to tarantulas and may live from several to 20 years. Predators of the Trapdoor Spider include Spider Wasps, scorpions, birds, centipedes and flies.
- Primary photo of Trapdoor Spider provided by Brian Powers, neighbor of MG Linda Esser
- Close-up of Trapdoor Spider, Lick Creek Park, College Station, TX, 06-2010, Photo #865-24: http://www.asergeev.com/pictures/archives/compress/2010/865/jpeg/24.jpg
- Trapdoor Spider Burrow: http://creationwiki.org/pool/images/d/d5/Trapdoor_spider_burrow.jpg
Research References / Resources:
- Animal Corner, Trapdoor Spider: https://animalcorner.co.uk/animals/trapdoor-spider/
- University of Arkansas Arthropod Museum Notes, #58, July 8, 2008, by Jeffrey K. Barnes: http://www.uark.edu/ua/aerthmuse/trapdoor.html
- “Common Spiders in the Landscape,” by Stephen Bambara, Ext. Entomologist, NC Cooperative Extension’s Ornamentals and Turf, Dept. of Entomology Insect Note: https://www.ces.ncsu.edu/depts/ent/notes/Other/note137/note137.html
- National Wildlife Federation’s Field Guide to Insects and Spiders of North America by Arthur V. Evans
Author: Jim Revell, Bedford Extension Master Gardener
Source: Aug 2017 Trapdoor Spider
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Get to know your insect neighbors! As always, feel free to contact your local Extension Master Gardeners with questions or concerns you may have about insects in your area.