Abstract: 【Aim】 The effect of low-temperature acclimation on the contents of related physiologically active substances was determined in Octodonta nipae (Coleoptera: Chrysomelidae) to reveal its cold tolerance mechanisms. 【Methods】 We compared the contents of different physiological substances such as free water, protein, amino acids, crude fat, glycerol and soluble glycogen between the non-acclimation (25℃) and acclimation (acclimated at 12.5, 15.0, 17.5 and 20.0℃ for 10 d) treated O. nipae. 【Results】 The contents of related physiologically active substances in O. nipae were significantly affected by acclimation temperatures. With the decrease of the acclimation temperature, the contents of glycerol and amino acids increased, while those of the free water, protein, crude fat and glycogen decreased. Compared with the control, the contents of free water in O. nipae subjected to acclimation at 12.5℃ had significant changes (P<0.01). The contents of protein and crude fat significantly changed when O. nipae was subjected to low-temperature acclimation at 12.5, 15.0, 17.5 and 20.0℃, so did the content of the amino acids except under acclimation at 20℃ (P<0.01). Low temperature acclimation-mediated effects on glycerol content were found in O. nipae at different developmental stages except the 2nd instar larvae. Significant changes in the contents of soluble glycogen were determined in different developmental stages except the 2nd instar larvae, pupae and adults after being acclimated at 12.5, 15.0, 17.5 and 20℃, respectively. The average glycerol content in O. nipae after being acclimated at 15.0℃ was about 9.4 times higher than that at 25℃. However, after O. nipae was acclimated at 12.5℃, its average glycerol content increased only 3.5 times as compared with the control. 【Conclusion】 These results indicated that the effect of low-temperature acclimation on the contents of related physiologically active substances in O. nipae was limited. O. nipae could make the optimal physiological adjustments based on the adverse environment conditions to adapt the future environment and maximize their fitness.

Key words: Octodonta nipae, low temperature acclimation, physiologically active substances, water content, protein, amino acids, fat, glycerol, glycogen