| Field and laboratory experiments investigated the affect of host plant quality on conspecific host discrimination by two specialist phytophages, Manduca quinoquemaculata and Manduca sexta, the tomato and tobacco hornworm moths (Lepidoptera: Sphingidae), and development of M. quinquemaculata larvae and adults. Results of these experiments were utilized to examine the hypothesis that female host preference is correlated with subsequent larval performance.; Higher rates of fertilization produced plants that conferred the highest fitness on larvae reared on foliage from these plants. Increased food efficiency, growth, survival and fecundity were correlated with mean percent total plant nitrogen and soluble nitrates. In addition, moth response, measured as the percent of total eggs deposited and the percent of plants with eggs, was highest on plants treated at higher rates of nitrogen fertilization. Finally, plants most preferred by moths permitted larvae to obtain the highest overall fitness. |
