Physiological performance of field-released insects.

Predicting insect field performance has direct value for control programmes seeking increased efficacy while simultaneously providing insights into field physiology and responses to environmental variability. Recent studies of field-released insects have made significant progress in three main areas. First, the trade-offs associated with thermal history relative to abiotic conditions on a given day have been repeatedly demonstrated in several taxa. Cold-acclimated insects released into hotter environments typically suffer performance costs-but do better than controls-in cooler environments suggesting both costs and benefits to physiological adjustments. Second, molecular mechanisms explored to date suggest complex underlying associations with recapture rates. Third, there has been significant progress in strengthening the link between traits scored in the laboratory as indicators of field performance. The overarching conclusion from this developing field suggests that physiological adjustments can make large, and in at least several cases, predictable changes in performance under field conditions. Further research is likely to contribute important insights into variation in field performance of insects.