Reznik, S. Y. 2010. On the effects of diet and photoperiod on Harmonia axyridis (Pallas)(Coleoptera, Coccinellidae) larval development. Entomological Review, 90(4), 411-414.

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It is known that the light day length and diet could act as cue factors inducing adult (reproductive) diapause in aphidophagous coccinellids. However, the rate of coccinellid larval development could also depend on photoperiod and diet. The present study examines effects of photoperiod (L:D=12:12 or 16:8) and diet (the green peach aphid Myzus persicae or eggs of the Angoumois grain moth Sitotroga cerealella) on preimaginal development of the multicolored Asian lady beetle Harmonia axyridis. At 20C, the short light day and feeding on aphids shortened larval development for 1.4 and 4.6 days, respectively. In combination, both factors caused a simple sum of separate impacts indicating the absence of their interaction. The duration of the pupal stage was independent of photoperiod, but decreased for 0.3 days in individuals fed on aphids. The proportion of the larvae that successfully completed preimaginal development was also independent of the light day length, but significantly depended on diet (84 and 60% in individuals fed on the green peach aphids and on the grain moth eggs, respectively). In sum, these results suggest that in the case studied, diet does not play a role of cue factor, but directly influences H. axyridis larval growth and development.