Arabidopsis Genotypes Resistant and Susceptible to Diamondback Moth (Lepidoptera: Plutellidae): No Net Effects on Insect Growth

The diamondback moth, Plutella xylostella (L.), is a pest of the Brassicaceae, including the model plant Arabidopsis thaliana (L.) Heynhold. Ecotypes of Arabidopsis have previously been reported to vary in the amounts of leaf area consumed when fed on by diamondback moth larvae. In the present study, food consumption varied among plant lines previously identified as either susceptible or resistant, but larval growth did not differ. Digestive efficiency varied inversely with food consumption. Thus, larvae compensated for reduced digestive efficiency by increasing consumption such that they achieved similar growth rates on all the Arabidopsis lines tested. We conclude that leaf area consumed alone may not be an ideal parameter for determining insect resistance.