The effects of temperature on the web-building behaviour of the common house spider, Achaearanea tepidariorum

1. Because spiders are ectothermic animals, the temperature regime of the microhabitat in which an individual finds itself may affect important performance traits of that individual, The present study examined the effects of temperature on attributes of webs spun by Achaearanea tepidariorum (C. Koch), as well as testing temperature preference in this species. The effects of temperature on the amount of silk per web produced by Achaearanea tepidariorum and the prey-capture efficiency of webs produced at different temperatures were determined by using webs constructed at 5, 10, 15, 20, 25 and 30 degrees C. The temperature preferences of A. tepidariorum within a thermal gradient were also determined, 2. Web mass was related to temperature, exhibiting a quadratic relation with a maximum web mass occurring at approximately 20 degrees C. 3. Number of strands per cm(3) of webs varied directly with web mass; webs with greater strand densities were more efficient at capturing flies. 4. The number of spiders observed in each temperature range in the thermal gradient indicated a non-uniform distribution, with the spiders avoiding temperatures in the highest range (27.3 +/- 2.0 degrees C). 5. These data suggest an optimal temperature for web construction at which webs produced are more efficient at capturing prey. The data also suggest that this species may avoid sites that do not provide an adequate thermal environment.