Effect of laboratory heat stress on mortality and web mass of the common house spider, Parasteatoda tepidariorum (Koch 1841) (Araneae: Theridiidae)

Abstract

We determined the effects of chronic heat stress on web construction of Parasteatoda tepidariorum (Araneae: Theridiidae) by measuring the survival and web mass of specimens after a 48-h period within a temperature chamber at 21, 30, 35, 40, or 50°C. The 21, 30 and 35°C treatments had the highest mean survival rate (100%), the 50°C treatment had the lowest (0%), and the 40°C treatment was intermediate (58%). The 21, 30, and 35°C treatments had the highest mean web mass, and the 40 and 50°C treatments had the lowest. Web mass did not correlate with spider mass for specimens across all temperature treatments. While acclimation temperature and humidity fluctuated throughout the 3 weeks of the study, neither variable affected web mass. This study demonstrates the sublethal effect of temperature on web construction, an effect that would ultimately be lethal in nature if a spider was unable to construct its web