A cost benefit approach to understanding the emergence patterns of nocturnal orb-weaving spiders.

Abstract

We developed a cost-benefit model to explain foraging behavior observed in Nuctenea spp. Based on the model, we predicted that 1) spider emergence would be negatively correlated with the abundance of spider predators; 2) spider emergence would be positively correlated with the abundance of insect prey; 3) spider emergence would be negatively correlated with ambient light intensity. We observed 78 spiders on five days and recorded spider emergence time, predator abundance, prey abundance, light intensity, wind speed and temperature. Regression analysis indicated a strong negative correlation between spider emergence and light intensity and weaker correlations between spider emergence and both predator abundance and prey abundance in the predicted direction. The role abiotic cues play in evolved strategies for avoiding predation are discussed.