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Western spotted orbweaver (Neoscona oaxacensis) male Photographs Taken in Dripping Springs, Texas, 6 June 2007 by Jerry Cates
Background: These spiders are present in large numbers in the superstructure over a private water treatment plant in the little Hill Country town of Dripping Springs. Females and males alike spin private webs to capture prey. Though both sexes are quite large, due to the quantity of prey that their webs capture each day, the male is still much smaller than the female. As the photo below shows, many of their webs are built on a horizontal plane, which is not typical for the species. However, prevailing winds are downward at this site, due to the action of the water treatment machinery, and that makes a web on the horizontal plane more useful than one on the vertical.
The male has a diminutive abdomen. Its pedipalps (the short appendages in front of the spider's mouth, which are easily seen in the photo below) are enlarged at their distal ends. These swollen tips encase complex structures that serve as reservoirs for semen; during mating, the pedipalps are used to transfer semen to the female's epigynum. The markings on the dorsal abdomen, shown in side view above, are ornate and complex, and similar to those of the female. These markings are definitive for Neoscona oaxacensis. The ventral markings on the male abdomen follow those of the female, and are also definitive for this species.
The photo above is of the male's ventral body. The sternum (ventral carapace) is usually white at its median aspect, with dark lateral margins, and dark coxae (the thoracic attachments for each leg). This specimen shows a white labium, just forward of the sternum; in other male specimens of this species the labium may not be marked so conspicuously. As with the female, in the center of the ventral abdomen is a square-shaped set of markings common to most species in the genus Neoscona. The square appears, in this species, as a black cross, with a staff and crossmember, the lower portion of the staff being broader than its upper portion. The cross divides the square into four sections, each of which, except for the black cross itself, is white. Posterior to this mark is an orange-colored square that delineates and surrounds the spider's complex of spinnerets. Photos of the female western spotted orbweaver... ---------------------------------------------- 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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