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Spinybacked Orbweaver
(Gasteracantha
cancriformis) mature female Photography by Lorraine E., text by Jerry Cates
This species has a hard abdomen armed with six spines, two pointed rearward, and two pointed to each side. Coloration varies considerably among races; in Florida the common race has a white abdomen with red spines, while in other locales the abdomen may be yellow, and the spines black. In this specimen, photographed by Lorraine E. in College Station, Texas, the abdomen is red, and the spines are black. Colloquially, this spider is often known as the "crab spider", not (as with the Thomisidae) because of the way it moves, but because the hard abdomen has the appearance of a crab's shell.
The orb web is similar to that produced by other orb weavers, but lacks the central stabilimentum produced by Argiopes, and often has a multitude of irregularly spaced tufts of silk scattered over the web. I count at least 22 radial strands in this web. Note the detail provided in the high-resolution photo below. This attests to the Lorraine's expertise as a photographer, and an unusually steady hand.
The bite of Gasteracantha cancriformis is not known to be harmful to man. The male (not shown) of this species may be found in every month except December and January where they are not subjected to freezing weather. Females are found as adults throughout the year.
Egg sacs are deposited on the undersides of leaves near the female's web. The eggs hatch in 11 to 13 days. ---------------------------------------------- We are investigating the risk of secondary infections that may occur as a result of bites from this and 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 |
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