| Abstract: | A series of experiments was conducted to ascertain the effects of temperature and allelochemicals on the performance of an insect herbivore, with the goal of methodically expanding the cumulative data set on interactive effects of temperature and allelochemicals. The allelochemicals examined were caffeine, chlorogenic acid, quercetin, tannic acid and tomatine with the thermal regimes 20:15 °C versus 30:15 °C. Growth, molting time and food utilization efficiencies of third instar tobacco hornworms (Manduca sexta (L.)) were measured. Our results indicated that reductions in developmental rate by the phenolics were primarily due to effects occurring around and during molt initiation, that different phenolics may affect molt processes differently, and that some of the effects of the phenolics were a function of temperature, with greater negative effects at cool temperature. Negative effects of caffeine were most pronounced earlier in the stadium rather than during molt processes and, for some variables, the effect of caffeine was also a function of temperature. |
