Larval Host Preference and Suitability for the Sawfly Mesoneura rufonota among Five Cinnamomun Tree Species

The camphor sawfly, Mesoneura rufonota Rohwer, is an economically important leaf-chewing pest of the genus Cinnamomum Trew. However, little is known about the range of species that it can infest within this genus or whether larvae show preferences for particular species. We conducted preference and performance experiments under laboratory conditions to assess larval host preference and suitability as a host plant of five congeneric trees species: C. camphora (Linn) Presl, C. bodinieri Levl., C. burmanni (Nees et T. Nees) Blume, C. pauciflorum Nees, and C. micranthum (Hay.) Hay. In no-choice, two-choice and multiple-choice feeding trials, significantly higher feeding rates were found on C. camphora, followed by C. bodinieri, compared to those on the other three tree species. In two-choice behavior trials, larvae moved to occupy leaves of C. camphora faster and more frequently, followed by C. bodinieri, than when offered the other three tree species. In no-choice fitness trials, the survival of larval and pupal stage was the highest, the developmental duration of larval and pupal stage was the shortest, the pupal body weight was the heaviest and adults lived the longest on C. camphora followed by C. bodinieri, while M. rufonota did not complete development on C. burmanni, C. pauciflorum or C. micranthum. Our results demonstrate that larvae consistently prefer and perform better on C. camphora leaves, that they can utilize C. bodinieri, but it is less preferred, and that C. burmanni, C. pauciflorum, and C. micranthum appear to be unsuitable as a host for M. rufonota.