Abstract: Ladybird beetles often face temporary food shortage during their life. We examined effects of food shortage on Harmonia axyridis development using the 4th instar larva as the testing insect, one of the most starvation-resistant stages, and the bird cherry-oat aphid Rhopalosiphum padi as the prey. We examined larval development time, survival, adult body size and longevity as affected by starvation and initial larval body weight. H. axyridis larvae did not survive to pupation under the "no feeding" and "feeding for 1 d" treatments. In the "feeding for 2 d" treatment, pupation rate increased from 46% with increase in the initial body weight, while all the larvae pupated in the treatments of feeding for 3 and 4 d without relation to the initial body weight. Larval duration was influenced by both starvation and the initial body weight, decreasing by 58% and 30% under "feeding for 3 d" and "feeding for 4 d" compared to "feeding for 2 d", respectively. The larval duration decreased with increase in the initial body weight under the treatments of feeding for 2 and 3 d. Adult body weight was affected by starvation only, not by the initial larval body weight, increasing by 63.7% and 72.5% under the treatments of feeding for 3 and 4 d compared to the feeding for 2 d, respectively. Adult longevity increased by 27.5% for the "feeding for 4 d" compared to the "feeding for 2 d" treatments. The results suggest that the H. axyridis 4th instars require feeding for more than 2 days on aphids for their development to adults.

Key words: Harmonia axyridis, development, nutrition ecology, life history, Coccinellidae