Mortality risk of rapid growth in the spider Nephila clavipes

1, Female Nephila clavipes from univoltine populations have greatly reduced reproductive success if they grow slowly and reach maturity late in the gr owing season. Although such fitness costs are expected to select for rapid increases in mass, several authors have presented models and data describin g physiological costs of rapidly increasing mass. 2, In order to test the hypothesis that there are inherent costs of rapid g rowth (increasing mass), laboratory-reared juveniles of the orb-weaving spi der Nephila clavipes were randomly assigned to receive daily feedings rangi ng from 2.5% to 23% of their initial mass. 3, Spiders receiving higher amounts of food were more likely to die at or i mmediately before the next moulting cycle. 4, These results indicate that there may be inherent physiological costs of rapidly increasing mass. In opportunistic feeders such as spiders that ten d to gorge when prey are abundant, this could present a real cost to a comm on foraging strategy.