Thursday, June 7, 2012

Tarantulas go a-courting

My captive, 7+ year-old Texas brown tarantula was given me
 by PMP, Tim Sloane, who collected it from an urban backyard.
This has been tarantula week in Dallas. I don't get too many tarantula calls as a rule; tarantulas are nocturnal homebodies, rarely venturing more than a foot from their burrow...except during mating season. For a short time in the spring (and to some extent in the fall), usually after a rain, male Texas brown tarantulas (Aphonopelma hentzi complex) leave their burrows and hidey-holes in search of--what else?--romance. In some parts of the state dozens of spiders may be seen at once, especially at night along lonely west Texas highways.

According to Burr Williams of the Sibley Nature Center in Midland, who has observed tarantula courtship in west Texas, once a male catches a female's pheromone scent, they seem very good at orienting to a female's burrow. The male taps at the entrance and the female lunges out. The male grabs her, mates quickly, and it's over--sometimes permanently for the male.

Most authorities (e.g., Thomas Prentiss in Ubick et. al, Spiders of North America) say that mature male tarantulas don't live long. Whether this is because they usually get eaten, or just don't have what it takes to be a long-liver (females have been observed to live 30 years in captivity), I'm not sure.  But the male spider I placed yesterday in a terrarium with my 7-year-old female Texas brown Tarantula certainly didn't last long. This morning a leg and a few unidentifiable scraps of carapace were all that was left. I can only hope he enjoyed his final moments.

According to a 1999 study by Margaret Janowski-Bell and Norman Horner--who put little radio antennae on the backs of tarantulas and followed them around the desert (how cool is that!)--males in the wild may visit multiple females, and thus must have a better chance of escape from the than my unlucky captive.

Most of the folks who called about tarantulas this week seemed worried.  One gentleman was worried that his child would be bitten. Another was ready to sell his house and move (presumably as far away from Texas as possible) after finding his backyard and and exterior walls of his home hosting multiple tarantulas. 

Fortunately, tarantulas are not that dangerous. Forget Spielberg's Arachnophobia if you can, a tarantula is a shy giant of a spider. The venom is not considered especially toxic, on the order of a bee sting. But the chance of being bitten by a tarantula is slim. Add to that the fact that tarantulas, like all spiders, do much good by controlling the general insect population.

A tarantula mysteriously ended up on
Dr. Knutson's shirt while gardening in his backyard. 
Having said this, I am likely to undo all my "spider good will" by sharing a recent adventure of my friend and colleague, Dr. Allen Knutson. Allen lives in an older neighborhood of McKinney, Texas.  He and his wife notice tarantulas from time to time on walks in their neighborhood. Nevertheless it was a shock for wife when Allen walked into the kitchen after working in the garden recently with a hitchhiking tarantula. Thinking she was making a lot of fuss over a little spider, even entomologist Allen was surprized to find a 4-inch male tarantula clinging to his back.  After being quickly shooshed out of the house, Allen was brave enough to stand for the accompanying picture. He noted matter-of-factly that the spider looked much bigger in real life than it does in the picture. I'm sure.

Try as I might I can't force myself to encourage the pest control industry to kill tarantulas.  Yes, I know it's what some of your customers want. But to me tarantulas are just way too cool, and deserve their little hole in the ground where they (almost) never bother anyone.  So this is what I'm going to do--we'll compromise. According to my arachnologist colleagues, science has a need for tarantula specimens. If you collect a tarantula, I will accept it (live or dead) and send it to the spider community via the Texas A&M University insect collection. If you kill it first, put it in a jar of alcohol to preserve it, otherwise bring it live to my office, following the instructions on this page. I'll make sure the little guys and gals don't die in vain.

Tarantulas are a sign that things are as they should be. They represent a healthy ecosystem where pests must fight for their miserable lives. And they're a sign of Texas. After all, what would Texas be without its prickly pears, tarantulas, scorpions, rattlesnakes and brown recluses? I know one thing for sure. It wouldn't be Texas.


Dempsy Winans said...

We were at a family Christmas gathering in Rhome, TX, a little northof Fort Worth, when I was about 6 or 7 years-old. All the kids were outside playing in the yard and my cousin hollered for us to come see the giant spider. We all ran over and he wasn't joking, there was a spider there as big as a Volkswagen Beetle, with legs about 4 feet long and a body as big around as a 55 gallon barrel! Well, at least it SEEMED that big to me at the time. One of the kids grabbed a big rock and was going to bash the spider with it but when they threw the rock, it missed and the Tarantula JUMPED about 3' off the ground, sending us all racing away in a panic! I had no idea what it was other than "a giant spider." Later I learned that it was a Tarantula but I can tell you that it scared the bejeezus out of me and I didn't want to play in that yard again for a long, LONG time. I didn't realize they were native Texans until many years later and it's only been in the past few years that I have realized they are actually VERY good creatures to have around. I'm with Mike on this one, I would have a real problem with killing them because they do so much good and pose so little of a threat as to be safe, as far as I'm concerned.

Mike Merchant, PhD said...

Dr. Norman Horner, Midwestern State University, shared the following information with us about the male tarantula:
"I firmly believe that once a male reaches maturity it will be dead in a few months. Their sole purpose is to mate and since most females are going to have to mate again (female tarantulas are one of a few females spiders that undergo ecdysis after becoming sexually mature – they shed any remaining sperm from the previous year’s mating) to receive sperm in order to be able to fertilize eggs."

Mike Merchant, PhD said...

Dave Moellendorf of Austin Arachnological Services also adds a few additional comments worth sharing:

"This is the month when our common Texas tarantula Aphonopelma hentzi sends out its first wave of males which generally mature at the same time in search of females....the males have to wander in order to find the burrow dwelling females."

Furthermore, it turns out that the timing of mating activities of different species varies in different parts of the state. He says, "In Texas, Aphonopelma hentzi has two waves of males...once in May-June, the other in October-November. The Aphonopelma anax complex of S. Texas and the Coastal region is usually April-May, as is Aphonopelma armada, and the other border and west Texas species usually in June......

Pest Removal London said...

That tarantulas are not an immediate threat and are integral to keeping the balance in the ecosystem is a piece of information that should be made known to more people. People should be able to identify what qualifies as real pests; those critters that pose a real threat to human and animal life and damage to property.

Stinger said...

I think most people just overreact something like bed bugs where that creep factor just continues forever. We service the Metro Phoenix area and seldom really run into the tarantula on the move. We do try to move them along with rattlesnakes and wildlife, they're just doing what natures whats them to do. The size often scares people but once again you put things into perspective. Thanks Mike

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