Current Issue

Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Nocturnal hunters: Mexican redrump tarantula, Brachypelma vagans


This large female tarantula was living in a burrow beneath a stone.


During winter break, some adventurous students from the University of Maryland participated in a course transporting them from chilly North America 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 grip of winter and stow away on this tropical odyssey. In chronicling this adventure, our first stop includes a visit to the nocturnal rulers of the epigeal realm. While prowling around a garden near Clarrisa Falls in search of spiders, several students discovered a beautiful redrump tarantula hiding in its burrow beneath the root of mango tree.

After patient enticement with the mid-vein of a large leaf, the curious spider dashed from its hole to investigate the cause of the disturbance. This grand appearance provided a splendid opportunity to examine the gorgeous creature. The tarantula entertained the students while exploring their hands and graciously allowed the class to inspect its powerful fangs while being wrangled by a bug geek.


This beautiful tarantula seemed as curious about humans as humans were about it.

Much lore and misinformation surrounds these fascinating predators. Tarantulas are named after Taranto, a city in southeastern Italy on the Ionian Sea. In the 15th through 17th 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. Legend had it that the disease could only be cured by listening to lively frenetic music, called the 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.

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.


Powerful fangs are used to capture and immobilize prey.

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 potentially 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, he busts his best move which may include drumming, waggling of legs, and other gambols. This dance helps his mate recognize her suitor as a member of the same species. We all know how disagreeable it is to misidentify 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 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 known as urticating hairs. When the human encounter became just a little too unsettling, the spider raised its abdomen and expelled hairs by rubbing them off with the hind legs. These irritating hairs can lodge in the eyes or nasal passages of a would-be predator and thereby thwart an attack. After issuing a warning, our spider regained its composure and the arachnid wranglers suffered no discomfort or further threats.

On several visits to the Belizean rainforest we have encountered tarantulas, enjoyed their company, and returned them to their galleries. However, due to habitat destruction and collecting for the pet- trade industry, tarantulas in the genus Brachypelma are threatened and now protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora laws. These regulations prohibit the international trade of more than 34,000 species of wild animals and plants to prevent their extinction.


We thank the hearty crew of BSCI 339M: ‘Tropical Biology in Belize’ for providing the inspiration for this Bug of the Week, and several patient and brave students that extracted the tarantula from its hole and experienced a close encounter of the arachnid kind. 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 site: