Abstract:

 The effects of host plant species on oviposition selection, growth and development, reproduction and longevity of Diorhabda rybakowi, a main pest on temperate desert grassland, were investigated by recording, the biological characteristics of D. rybakowi, such as the developmental duration, survival rate of different developmental stages, emergence rate, adult longevity and fecundity, reared on the plants of Nitraria tangutorum, N. sphaerocarpa and N. roborowskii. The oviposition preference for the three host plants and contents of soluble sugar, starch and free amino acid in the leaves of the plants were also measured. The results showed that, the numbers of eggs laid by the female adults of D. rybakowi and proportion of eggs on the three host plants ranked from high to low were N. tangutorum, N. sphaerocarpa, and N. roborowskii. D. rybakowi were able to develop normally when feeding on the three host plants. The larval development duration was the shortest (13.05 d) when the larvae were fed with the leaves of N. tangutorum, and the longest (16.70 d) when fed with the leaves of N. roborowskii. In contrast, the larval survival rate was the highest on leaves of N. tangutorum (97.78%), but was only 10.54% on the leaves of N. roborowskii. The longevity and fecundity of adults emerged from N. tangutorum were the largest, and the opposite was with the adults emerged from N. roborowskii. Correlation analysis showed no significant correlation between the either soluble sugar, starch or free amino acid contents and pupal duration, adult longevity, hatching rate, or emergence rate of D. rybakowi. The larval development duration was negatively correlated with nutrient contents and positively correlated with the ratio of sugar to nitrogen. The oviposition and overall larval survival rate were positively correlated with the contents of nutrients, and negatively correlated with the ratio of sugar to nitrogen. These results indicate that N. tangutorum is the most suitable host plant for D. rybakowi.

Key words:

 host plants; Diorhabda rybakowi, growth development, reproduction; nutrients