Thermal activity thresholds of the predatory mirid Nesidiocoris tenuis: implications for its efficacy as a biological control agent

This study investigates the thermal activity thresholds of the predatory mirid Nesidiocoris tenuis Reuter (Hemiptera: Miridae) and two spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). Adult N. tenuis lost locomotory function and entered chill coma at significantly lower temperatures (4.0A degrees C and 0.3A degrees C, respectively) than adult T. urticae (7.0A degrees C and 5.7A degrees C, respectively). However, the mirids were more adversely affected by high temperatures, with T. urticae losing the ability to walk and entering heat coma at higher temperatures (47.3A degrees C and 49.7A degrees C, respectively) than N. tenuis (43.5A degrees C and 46.6A degrees C, respectively). Across a range of temperatures (2.5-20A degrees C) adult N. tenuis had faster walking speeds than T. urticae. These data are discussed in relation to the climatic conditions under which N. tenuis would be an effective biocontrol agent.