THE INFLUENCE OF CONSTANT TEMPERATURES ON THE NON-DIAPAUSE DEVELOPMENT OF HYSSOPUS THYMUS (HYMENOPTERA: EULOPHIDAE)

Abstract

AbstractThe influence of constant temperatures on the non-diapause development of Hyssopus thymus was studied and the results of these studies are presented. A lower threshold for development of less than 12 °C and an upper threshold of about 32 °C were determined. Mean times for and rates of development at different temperatures are presented for all developmental stages. The egg is the stage most sensitive to temperature change. Regression equations describing the relationship between the rate of development and temperature for these stages are given and a thermal constant (K) of about 190 degree-days is calculated for total development. This constant is not applicable to naturally fluctuating temperatures. The results of these studies are discussed in relation to the potential impact of H. thymus on European pine shoot moth dynamics under different climatic conditions. It is concluded that H. thymus should be more effective in warmer seasons and at lower latitudes.