Effect of Temperature and Humidity on the Population Abundance of Spotted Oriental Cucumber Beetle Epilachna chrysomelina (F.) (Coccinellidae : Coleoptera) In Al – Qunfudah Western Saudi Arabia

Abstract

The thermoregulatory behavior of the giant keyhole limpet Megathura crenulata was determined in a horizontal thermal gradient during the day at 18.9. °C and 18.3. °C for the night. The final preferendum determined for giant keyhole limpets was of 18.6±1.2. °C.Limpets' displacement velocity was 10.0±3.9cmh-1during the light phase and 8.4±1.6cmh-1during the dark phase. The thermotolerance (measured as CTMax at 50%) was determined in a keyhole limpet in three acclimation temperatures 17, 20, and 23°C. Limpets were subjected to water increasing temperatures at a rate of 1°C every 30min, until they detached from the substrate. The critical thermal maximum at 50% was 27.2, 27.9 and 28.3°C respectively.