|
Southern house spider
(Kukulcania
hibernalis) male Photography and text by Jerry Cates Considered essentially harmless, though will bite if handled; often mistaken for brown recluse (Loxosceles) spiders
I found this harmless spider in a home in central Texas in 1995. Among the vials in my lab that contain pickled specimens of spiders collected over the past 27 years, this species is represented most often. That's because its markings, on the dorsal carapace, resemble those of the feared brown recluse spider (Loxosceles reclusa). Some of the best authorities in the field of arachnology claim that the brown recluse is common in Texas, yet while I've collected spider specimens from all over the state, I've never found one. My pest management work beyond Austin, Round Rock, and Georgetown, has mainly involved nursing homes and hospitals, which may explain why the brown recluse and I have never crossed paths before. The Southern House Spider, by comparison, is so abundant that I've collected specimens in Midland, Odessa, Abilene, Brownwood, Dallas, Fort Worth, Houston, San Antonio, Round Rock, Austin, Georgetown, Mount Pleasant, Corpus Christi, and in other locations. It is too bad I cannot provide a specimen from my collection to show the peculiar anatomical features of the brown recluse. However, while the Southern House Spider is not known to harm those it bites, the brown recluse may leave lesions that take months or years to fully heal.
The eight eyes of the southern house spider (K. hibernalis) are arranged in two semicircular rows upon a somewhat hairy protuberance in the anterior median portion of the spider's otherwise hairless carapace. Each row has four eyes that stretch across the face of the protuberance. The eyes of the brown recluse look nothing like this. Instead of eight, that species has only six, arranged in a single row of three pairs, one of which faces forward, while one of the other pairs faces to the right, the other to the left.
The photo above provides a close up view of the distal ends of the chelicerae (fangs) of the male southern house spider. As with all true spiders, the fangs are hinged so that they open and close laterally, like scissors. The two hairy objects pressing against the upper portion of the chelicerae are pedipalps. In the male of this species, the pedipalps are quite long, resembling an extra set of legs. However, they are specially adapted for use in copulation and are, therefore, wholly unsuitable for use in ambulation, for reasons that become clear by viewing the photo below:
When the pedipalps are withdrawn from their "parking" position against the chelicerae, the hardened, spiral emboli at each end are exposed. These are used to transfer sperm to the female's epigynum. ---------------------------------------------- Though the Southern House Spider (Kukulcania hibernalis) is capable of biting humans, its bite is not considered harmful. We would like to hear of your experiences with such bites. We are also investigating the risk of secondary infections that may occur as a result of bites from other, otherwise harmless spiders whose venom is known to pose little or no danger to humans. In the process, we are collecting information on experiences persons have had with such spider bites. Please contact us about your personal experiences, if you have been bitten by this or any other spider, including jumping spiders and garden spiders (the bites of which typically produce a transitory inflammation, but resolve within a few days without medical attention), whether recently or in the past thirty years, anywhere in the world. For example, the bite of a species of garden spider, the golden orb spider of Australia [Nephila edulis] typically is unremarkable, but on occasion produces medically significant secondary infections; the frequency and nature of bites experienced from that species of spider is also a part of this study. The object of this study is to collect data that might relate to a mysterious series of spider-related infections, involving a special pathogen, that took place in the United States and in Australia between 1977 and 2006. Although only fifteen such infections were reported to medical establishments, seven appear to be associated with spider bites. Some authorities suggest that the number of actual infections of this type that occurred in the U.S. and Australia during the past thirty years is much larger, but that they have been underreported. Underreporting of specific kinds of infections can occur, either because the persons infected chose not to seek medical assistance, or the medical establishments misdiagnosed the infections as being caused by other infectious agents. We are seeking to establish an estimate of the number of human spider bites that occur each year by these and similar spiders, whether the bite resulted in injury to the human or not. Next, we hope to establish the number of instances where the bite (1) became inflamed and/or infected, then resolved without medical intervention, or (2) infected, ulcerated, or led to a generalized sickness, and required medical intervention. ---------------------------------------------- Back to: Texas Spiders Back to: Bugsinthenews |
|||
