Johnson, N.D., K.S. Williams, and P.R. Ehrlich. (1987) Effects of chemical fertilization of Diplacus aurantiacus on the development and persistence of the postdiapause larvae of its Lepidopteran herbivore Euphydryas chalcedona. American Midland Naturalist 117: 435-438.
Diplacus aurantiacus is one of the primary host plants of Euphydryas chalcedona in coastal California. The authors placed equal numbers of E. chalcedona post-diapause larvae on fertilized and unfertilized D. aurantiacus plants. Larvae developed more quickly and were more abundant on the fertilized than on the unfertilized plants. These results for postdiapause larvae in the field are consistent with published studies of E. chalcedona prediapause larvae in the laboratory and field, and of post-diapause larvae in the laboratory.
