Is Optimal Foraging a Realistic Expectation in Orb-web Spiders?
Will Edwards, Poppy A. Whytlaw, Bradley C. Congdon, and Chris Gaskett Ecological Entomology, Vol 34, 2009, pp 527-534 1. Explanations for web relocation invoking optimal foraging require reliable differentiation between individual sites and overall habitat quality. We characterised natural conditions of resource variability over 20 days in artificial webs of the orb-web spider Gasteracantha fornicata to examine this requirement. 2. Variability in catch success was high. Day-to-day catch success in 90% (18/20) catch sites fitted negative binomial distributions, whereas 10% fitted Poisson distributions. Considered across trap sites (overall habitat), variance in catch success increased proportionally faster than the mean (i.e. Taylor’s Power Law, variance = 0.54 mean 1.764). 3. We compared the confidence intervals for the expected cumulative catch in randomly drawn sequential samples from a frequency distribution representing the overall habitat (based on the parameters for Taylor’s powe
