Abstract: Harmonia axyridis, an important predatory natural enemy, also feeds on pollen under natural conditions. To explore the potential of using canola pollen in breeding of H. axyridis, this experiment evaluated the effects of pollen solution (9.1%, 23.1%, 33.3%, and 41.2%) on the growth and development of the predator larvae, with the dry pollen as the control (CK). After that, the effects of canola pollen solution supplied as supplementary food under Myzus persicae shortage condition on the larval development and adult reproduction of H. axyridis were further explored. The results showed that, the survival rates of 4^th instar and pupa (48.9% and 37.8%) and the female adult weight (18.9 mg) of the 23.1% pollen solution group were significantly higher than those of other treatments, while the total development time (27.3 d) of these beetles was significantly reduced. When the 23.1% pollen solution was used as supplementary food, the larval development and adult reproduction, i.e., survival rate, pupation rate (93.3%), eclosion rate (84.4%), egg production (231.7) and hatching rate (34.8%) of H. axyridis were significantly higher than those of the predators fed with aphids only, while the pre-oviposition period was significantly reduced (18.0 d). Our results showed that the 23.1% canola pollen solution was most suitable for the larval development of H. axyridis, which can greatly improve the survival and adult fecundity under M. persicae shortage conditions. These findings are of significance for rearing predatory ladybird beetles with canola pollen and shed light on the cultivation of B. napus in agricultural fields for conserving natural enemies.

Key words: pollen, natural enemies, functional plant, development, reproduction