Life table determination of thermal requirements of the tomato borer Tuta absoluta

Abstract

Temperature is one of the main factors affecting insect populations. The models used for studying the effect of temperature on insects are usually based on insect developmental rates. However, life table parameters such as the (intrinsic) population rate of increase (r m), which reflect the overall effect of temperature on the development, reproduction, and survival of the insect, should also be considered. The leaf miner Tuta absoluta (Lepidoptera: Gelechiidae) is an invasive tomato pest across several regions of the world with its range currently expanding because of its spread into the Middle East and Asia. Thus, this study aimed to assess the impact of temperature on T. absoluta and to determine the thermal requirements for this pest based on life table parameters. For this purpose, bioassays of the development and reproduction of T. absoluta under constant temperatures (17, 22, 26, 28, 30, and 33 °C) were performed. The thermal requirements of T. absoluta were assessed from r m. We found that the immature mortality of T. absoluta was lowest at 28 and 30 °C and highest at 17 °C. The optimum temperature for T. absoluta was 30 °C with upper and lower developmental thresholds of 34.6 and 14 °C, respectively. These thermal requirements were different from those that can be estimated from the rate of insect development. The results of this study would be helpful toward developing phenological, spatial, and temporal distribution models for T. absoluta and toward determining optimal management strategies for this pest species.