Effect of Elevated Temperature on Development Time of Rice Yellow Stem Borer

Insects, as cold-blooded animals are directly under the control of temperature for their growth and they cannot sustain living below and above certain thresholds. Therefore, temperature is probably the single most important environmental factor influencing insect behavior. Current estimates of changes in climate indicate an increase in global mean annual temperatures of 1°C by 2025 and 3°C by the end of the next century. Such increases in temperature may decrease the developmental time and increase the number of generations per year. An investigation was adopted to understand the effect of five different constant temperatures (28.3°C, 30.6°C, 32.7°C, 34.3°C and 36°C) on the development time of Yellow Stem Borer (YSB). The results revealed that the number of eggs laid by YSB increased at higher temperatures while egg hatching was reduced. Egg hatching was higher (90.6%) in 30.6°C followed by 28.3°C. The development time taken by different stages of the YSB revealed that there was an inverse relationship with development time and incubation temperature level. Insects develop faster which may oviposit early and hence the population was likely to grow earlier than expected.