Cryoprotectant contents of overwintering adults of elm leaf beetle, Xanthogaleruca luteola (Col.: Chrysomelidae)

The elm leaf beetle، Xanthogaleruca luteola (Muller)، is one of the most destructive pests of elm trees that overwinters as diapausing adult. The main cryoprotectants and their seasonal fluctuations in the elm leaf beetles were analyzed based on the monthly level of polyhydric alcohol from October 2008 through June 2009، using high performance liquid chromatography (HPLC). The compounds myo-inositol، trehalose، glucose and glycerol were found to be the most important polyols in the overwintering adults، of which myo-inositol content exhibited an inversely significant correlation with temperature fluctuations (r = -0. 814، P = 0. 014). The highest level of myo-inositol was observed in December (32. 6 ± 2. 7 µmol g-1 fresh body weight)، while its lowest level was recorded in April (3. 0 ± 0. 4 µmol g-1 fresh body weight). The total concentration of all cryoprotectants was 100. 7 ± 7. 6 µmol g-1 fresh body weights in January. The results underline the influential role of myo-inositol، trehalose and glucose compounds in enhancing the cold tolerance of elm leaf beetles and their chance of survival during freezing winter days.