Crab spider hunting performance is temperature insensitive

1. Laboratory and field experiments showed that the hunting performance of two flower-dwelling crab spiders, Misumenops asperatus and Misumenoides for mosipes, was thermally insensitive over a broad range of temperatures norma lly experienced by these spiders. 2. In the laboratory, HP, a behavioural metric of spider hunting performanc e, was similar for spiders of a given species over an approximate to 30 deg rees C temperature range. 3. Spiders in the field captured predominantly hymenopterans and dipterans, and field hunting performance, measured as the number of prey captured per spider per day, also proved to be unaffected by temperature. 4. These findings counter the general rule that physiological/ecological pe rformance in terrestrial arthropods is temperature dependent. 5. Freedom from temperature constraints on the capacity of crab spiders to capture prey may be due to the use of venom and/or to muscle physiological adaptations for anaerobic metabolism. 6. Wide thermal performance breadth increases the spectrum of prey availabl e to M. asperatus and M. formosipes by allowing spiders to hunt prey active during cooler periods of the day as well as those active during warmer per iods. 7. Wide thermal performance breadth also benefits M. asperatus and M. formo sipes due to adult phenology; both species experience a seasonal temperatur e shift during the adult phase.