Print PageHuman activities are causing global warming, which will increase mean temperatures, as well as the frequency, duration, and peak temperatures of heat waves (acute high-temperature events). Heat waves often decrease plant growth and reproduction by disturbing heat-sensitive processes and altering chemical composition; consequently, heat waves might affect plant-herbivore interactions. However, while much research has focused on moderate chronic warming and plant-herbivore interactions, little has examined effects of heat waves. We are investigating heat-wave effects on plant-herbivore interactions using the tomato (Solanum lycopersicum)–tobacco hornworm (Manduca sexta) model system. Tomato plants grown at 30°C were subjected to acute heating (+15°C) for 4 hours. After heating, previously-starved larvae were provided leaves from unheated controls or plants heated 1, 3, or 5 days before.
Results/Conclusions
Heating decreased leaf consumption by herbivores (P = 0.027), with the largest decrease in day-1, and smallest in day-5, leaves. There was also a corresponding trend in herbivore weight loss (decreases of 11.5, 3.2, and 1.1% of body mass loss for 1, 3, and 5 days after heating, respectively). Causes of herbivore weight loss while consuming heat-stressed tissue include potential negative effects of heat on plant tissue quality (decreasing protein, non-structural carbohydrates, or water content; increasing fiber, necrosis, and defensive compounds). These results indicate that heat waves associated with global warming will impact plant-herbivore interactions.
