More than 35,000 spider species have been documented worldwide, and only around 3,000 spider species are known to inhabit North America. Surprisingly, the majority of known spider species possess fangs that are too small to inflict penetrative bites on human skin, and the minority of spider species that have been known to bite humans are considered medically harmless. While both insects and spiders belong to the Arthropoda phylum, spiders are not insects, as some people believe; instead, spiders are arachnids that belong to the Chelicerata subphylum. The arachnid class also includes scorpions, sea spiders, whip scorpions, mites, ticks, harvestman and solifuges, just to name a few.
The medical community is largely in agreement that 13 recluse spider species, and three black widow spider species are the only medically significant spiders that can be found in the US. However, yellow sac spiders, hobo spiders, and brown widow spiders have also been documented as inflicting medically harmful bites on very rare occasions in the country. The brown recluse and the southern black widow are responsible for nearly all medically harmful spider bites reported in the US annually. Both of these spider species are prevalent in central Texas where they are commonly found within homes, often in large numbers. Unsurprisingly, a recent nationwide survey of pest management professionals revealed that the southern black widow and the brown recluse were the third and fourth most commonly controlled spider pests within homes during the 2016 year.
While spider envenomation incidents are commonly said to result from bites, this is not exactly the case. It is commonly believed that spiders liquify their insect prey in order to suck up the contents through a narrow straw-like structure located within each of their two fangs, and therefore, spider fangs do not just inject venom, they also serve as a mouth of sorts. Many ant, bee and wasp species possess a rear stinger to inject venom into their prey, but since their stinger does not double as a food consumption organ like the human mouth or spider fangs, these insects are said to inflict “stings,” not bites. In reality, spider fangs exist solely for the purpose of delivering paralyzing or deadly venom to their prey or to defend themselves, and not for consuming food. In fact, spiders consume liquified insect prey by using external mouthparts to shove food into a small hole below their fangs. This feeding hole functions as a spider’s mouth, which is why it’s literally called a “mouth.” Considering these facts, spider fangs are analogous to ant, bee and wasp stingers, so for the sake of accuracy, spiders actually inflict stings, not bites.
Have you ever sustained a spider “sting” within your home?