A leaf-disc-test method was used under controlled laboratory conditions to determine the feeding preference of Altica deserticola Latreille (Coleoptera: Chrysomelidae) on leaves of two liquorice species, Glycyrrhiza inflata Batalin and G. uralensis Fisch. ex DC. Leaf hardness and thickness, cuticle thickness, and nitrogen and tannin contents were compared between the two liquorices to explore their feeding resistance to A. deserticola. The larvae ate only G. uralensis leaves, while the adults fed on the leaves of both species but preferred those of G. inflata. The leaf hardness and thickness and cuticle thickness, as well as the nitrogen, total tannins, tannin chemicals contents in leaves, were significantly greater in G. inflata than in G. uralensis. The larvae having smaller chewing mouthparts could not feed on hard leaves with thick cuticle on both sides. The thicker cuticle and harder texture of G. inflata blades may be important physical traits for effective defence against larval phytophagy, while the higher tannin content in its leaves may be an important chemical trait determining their feeding preference. The larger adults, having stronger mouthparts, could consume nitrogen-richer G. inflata leaves to obtain the energy needed for flight and reproduction.
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