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Golden silk orbweaver (Nephila clavipes) adult female Report and Photographs Courtesy of Sandra R., Houston, Texas, 15 July 2007 Editor's Notes by Jerry Cates
Sandra Wrote: Jerry--I hope this is what you were asking for. How do I get photos of the spider's eyes?
Editor's Notes: What a beautiful photo! The golden-colored sticky strands of the web (the source of this spider's common name) are very obvious in this shot. Sandra took two photos, and this is the best of the two. I used it to illustrate a number of anatomical features in the enlargements provided below. I asked Sandra if she might take photos of the eyes, but that was probably asking too much, for several reasons. First, note the structure of the carapace, below, which is the thick plate covering the spider's combination head-thorax. The eyes are fixed in the frontal portion of the head, i.e., the face, and cannot be seen directly (see the dark protuberances, on the right-most portion of the head in the photo below? those are eyes, or at least the structures enclosing the eyes), when the spider is at rest, head-down in the center of the web, without getting into a crouch below the web and shooting up, toward the sky. Besides taking a greater risk of being bitten by this spider, such a shot would also have the sky as a backdrop, which would diminish the amount of detail in the spider's face. I asked Sandra not to take risks with this spider because although its venom isn't considered particularly harmful, the chance of a secondary infection from the bite is too great.
An alternative way of getting a good photo of the eyes would be to wait for the spider to become engrossed in feeding on an insect, then maneuver around to get a shot of its face. Again, however, it is important not to bump the web and possibly cause the spider to drop on your foot or worse, down a shirt or blouse. I repeat: the venom is not considered dangerous, but the risk of secondary infection remains (rare, yes, but it happens). The more I think about it, the less I want Sandra to try very hard to get a good photo of the eyes...
Nephila clavipes has an abdomen whose dorsal (upper) surface is marked with a multitude of white or pale yellow spots on a gold background. This specimen has seven pairs of somewhat larger white spots down the median of the dorsal abdomen, with an interesting arrangement of ancillary spots, some white, others black. Note that the first, third, and fourth pairs have black spots on their posterior peripheries.
The Conspicuous tufts of black hair adorn the first, second, and fourth legs on each side of the body. The tufts are positioned at the distal ends of the femur and tibia of each of these legs. While all spiders have at least two claws on the tips of their tarsi (the last segments on the legs) most orb-weavers--including this species--have three claws, consisting of the paired claws and an unpaired, median claw (some prefer to call it a hook). The median claw is smaller and provides special abilities to the spider during web-building. These photos do not permit enlarging the tips of the tarsi to show the claws. Such detail would likely only be possible from microscopy of a preserved specimen. Many thanks to Sandra for these excellent photos!!! And, Sandra, forget about getting photos of the eyes. Just enjoy this critter from a distance. It should give you lots of observational pleasure over the next few months. ---------------------------------------------- Please contact us about your personal experiences, if you have been bitten by a brown recluse, black widow, 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. One 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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