Last week a news story broke about a potentially dangerous neotropical (New World tropics) spider that stowed away in a crate of bananas from Latin America and ended up in a grocery store in Tulsa, Oklahoma. Credit the media for sticking with the story and getting it right for a change, successfully quelling what could have been needless widespread public hysteria.
Two experts in the case contradicted each other’s identification of the arachnid, and because the specimen was dispatched, there was no way to verify its identity. There are several species in the spider family Ctenidae, collectively known as “wandering spiders” because they do not spin webs to catch prey. Their large size and often aggressive behavior is enough to intimidate a person, regardless of how venomous they may be. The genus Phoneutria includes at least some species that can, rarely, deliver a lethal bite. Species in the harmless genus Cupiennius, however, can be easily mistaken for their deadlier cousins.
Richard S. Vetter and Stefan Hillebrecht addressed this dilemma in the cover story of the summer, 2008 issue of American Entomologist, a journal of the American Entomological Society. The bottom line from the article is that without close examination of a specimen, it is unlikely that an individual spider can be correctly identified. The better news is that fatalities from bites of Phoneutria are very rare, even for “at risk” populations such as the elderly and infants. It is largely one’s immune system response, rather than the toxicity of venom, that determines whether a bite will result in no reaction, a mild response, or a severe trauma.
Many of the reader response comments on the Yahoo version of the story centered on the perceived failure of our government inspection services. Dangerously venomous tropical spiders do not routinely infiltrate our nation, however, and the large volume of foreign shipments to the U.S. precludes comprehensive inspections. It is the price we pay for a “free market” where goods pass unfettered across borders. Collectively, through our demand for tropical fruits and houseplants, we consumers have determined that risks like spiders are an acceptable hazard.