Predicting optimal web size in orb weaving spiders: are nitrogen costs and benefits the whole story?

Webs spun by orb-weaving spiders vary in size and structure. Adaptationist theory suggests that this structural variation is not random but, instead, has evolved to maximize web performance. Sixty webs were examined, measuring area, density, and prey capture rates. A nitrogen assay was performed on prey and webs. A nitrogen cost-benefit analysis was used to determine maximum and optimum web size. Web area, but not density, was shown to influence prey capture rate. Nitrogen was not found to influence the distribution of web sizes. Therefore, additional ""hidden"" costs have been proposed.http://deepblue.lib.umich.edu/bitstream/2027.42/54243/1/2679.pdfDescription of 2679.pdf : Access restricted to on-site users at the U-M Biological Station