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Daylight length as a factor in web-building behavior of
an Araneomorphae spider

Nathan W. Fuller
nf1912@ship.edu

The purpose of this experiment is to determine the factors that influence the web-building behavior of a common central Pennsylvania orb-weaving spider. Specifically, I worked with light as the variable controlling the tendency of the spiders to undergo any type of web-tending behavior: web spinning, web removal, silk consumption, nest spinning and dragline anchoring. During casual observation of this same spider species in the city of Harrisburg, Pa, I observed a pattern of activity that was centered around sunset and twilight. It was during this time that spiders would take positions on their webs in wait of prey. If an individual had lost their web during the previous night or the web was badly damaged, this was the time when the spiders would construct new webs in place of their old.

For my experiment I decided to explore the influence on daylight length on this spider's web-building behavior. In the lab, I set up three groups of different light treatments on eight individual spiders. After a short period of conditioning, the individuals were observed for an hour during a simulated sunset event in which the source of light was a fifteen watt incandescent bulb. I recorded the positioning of the spider at the beginning of the test and recorded the movements they made for an hour. In addition to the lab, I also observed spiders in the field in Harrisburg, Pa on the Walnut Street Bridge. I hoped to record the behaviors of spiders during the time directly leading up to and following sunset. Specifically, my hypotheses were that the spiders would exhibit more web behavior during the sunset hour with resting stages during the day and sit-and-wait hunting a night.

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METHODS RESULTS DISCUSSION CONCLUSION ACKNOWLEDGMENTS