During winter break, some adventurous students at the University of Maryland participated in a course that took them on a remarkable adventure to the rainforest in Belize to study Mayan culture and learn about fascinating creatures and plants in tropical ecosystems. By some strange coincidence and a stroke of good fortune, Bug of the Week happened to escape the chilly grip of winter and stow away on this tropical odyssey. In chronicling this adventure, we visit nocturnal rulers of the epigeal realm. While prowling around a garden near Clarrisa Falls in search of nocturnal spiders, several students discovered a beautiful red-rumped tarantula near its subterranean burrow. The immature spider offered little resistance and no threat as students and teachers carefully examined the gorgeous creature. The following day a gardener excavated a large adult tarantula from its gallery and was rewarded with a blood-letting bite that proved no more than a minor nuisance.
This large tarantula was living in a burrow beneath a stone.
Much lore and misinformation surrounds these fascinating predators. Tarantulas are named after Taranto, a city in southeastern Italy on the Ionian Sea. In the 15’th through 17’th centuries legends told of the fearsome bite of the Italian tarantula that caused a condition known as tarantism. Tarantism was manifested by heightened excitability, restlessness, and sometimes an irresistible urge to dash about. The disease was believed to be cured by listening to lively up-tempo music, called Tarantella, or by engaging in a frenzied whirling dance that could last several days. Yikes! Talk about Saturday night fever. The culprit behind this mischief was actually a wolf spider, Lycosa tarantula, locally known as a tarantula. Wolf spiders belong to a family known as Lycosidae. True tarantulas such as the ones we encountered in Belize belong to a family of large hairy spiders know as Theraphosidae. These unusually large spiders sometimes measure almost a foot from tip to tip of their extended legs. They have remarkable longevity and can live in excess of thirty years. Their bite is memorable by virtue of some very large fangs hidden beneath the head of the spider. Fortunately, the bite of the Belizean tarantula is not very venomous and usually results in a bit of localized swelling, pain, and itching rather than a wretched death.
After receiving a minor bite from this large tarantula, a gardener takes a closer look.
Tarantulas are primarily nocturnal hunters of insects, other spiders, and small reptiles. However, some of the larger and more agile species have potent venom used to help capture small mammals and birds. After catching their victim with stealth or speed, they grind it into a ball, secrete digestive enzymes into the pulpy mass, and suck the liquefied contents into their mouth. Tarantulas have one of the most interesting mating rituals of any animal in the rainforest. The male tarantula is much smaller than his mate and to successfully sire a brood of young he places his life at risk in the presence of a hungry female. To complete his task, the male tarantula constructs a thin web on which he deposits sperm. Small leg-like appendages called pedipalps located near his jaws are used to pick up the sperm and carry it about. When he encounters a potential mate, a spidery dance ensues complete with drumming, waggling of legs, and other gambols. This dance helps the spiders recognize each other as members of the same species. We all know how disagreeable it is to meet members of another species when we are searching for a mate. With the preliminary introductions out of the way, the male warily approaches the female and does his best not to get eaten. The male tarantula is equipped with special claws on his front legs that help him grasp the female while he uses his pedipalps to carefully place sperm into a pouch on her underside. Sometimes the male escapes this romantic encounter, but sometimes he does not and he becomes dinner instead. The female tarantula lays several hundred eggs in a silken ball. These eggs are stored in the burrow and tended until they hatch. These large juicy arthropods would seem like a tempting meal for other predators in the jungle. However, in addition to sharp fangs, the tarantula has another potent defense. The abdomen of our tarantula was covered with a dense coat of hairs. When disturbed or threatened, the tarantula can expel these hairs from her body by rubbing them of with her legs. These irritating hairs can lodge in the eyes or nasal passages of a would-be predator and thereby thwart an attack.
References:
We thank the hearty crew of BSCI 279M: Tropical Biology in Belize for providing the inspiration for this Bug of the Week and Dr. Hellman for extracting a tarantula from its hole. Much of the information for this Bug of the Week came from Jerry G. Well's delightful book "The Guide to Owning a Tarantula". For more information on tarantulas, please visit the following web sites.
http://www.desertusa.com/july96/du_taran.html
http://www.brachypelmas.co.uk/just%20brachypelma/general%20info.htm