The effects of temperature on prey-capture kinematics of the bluegill (Lepomis macrochirus): implications for feeding studies
Research with ectothermic organisms has demonstrated that temperature is positively correlated with an individual's power output during locomotion. This study investigates the effect of temperature on another aspect of power output, prey-capture kinematics, of the bluegill (Lepomis macrochirus Rafinesque, 1819). Feeding sequences for two treatments of four sunfish were filmed at three temperatures (18, 24, and 30 °C) with one treatment (A) experiencing an increasing range of temperatures and the other (B) experiencing a decreasing temperature range. Directional temperatures affected prey-capture kinematics. The time required to achieve maximum lower jaw depression and maximum gape, as well as the duration of maximum gape, time to close the mouth (from the point of maximum gape), and the total bite duration, increased as water temperature decreased. In addition, both the time to maximum gape and the time to maximum lower jaw depression were longer at 18 °C for individuals in treatment A than those in treatment B. These results indicate that water temperature can bias the results of feeding studies employing kinematics that do not control for its effects as well as those that make comparisons across such studies which utilize different temperatures and taxa.