Now online: “Increased temperature alters feeding behavior of a generalist herbivore” by Nathan P. Lemoine and co-workers. Read more about how an increased temperature may affect plant growth and herbivory:
Temperature plays a crucial role in determining ecological processes. For example, temperature can control rates of predation, herbivory, individual growth rates, population growth rates, and mortality rates, to name a few. Unfortunately, we know little regarding the effects of temperature on herbivore choices. That is, we do not fully understand how temperature influences which foods herbivores choose to eat or which foods provide optimal diets. Herbivore physiology is strongly controlled by environmental temperature (if the herbivore is an ectotherm), as rising temperatures promote growth (to a point) and increase the demand for vital nutrients, like sugars, proteins, nitrogen, or phosphorus. If true, then daily, seasonal, decadal, or climatic fluctuations in temperature should alter the plants that herbivores consume.
We tested the hypothesis that temperature alters herbivore performance (consumption and growth rates) and feeding preferences among plant species using the Japanese beetle, Popillia japonica.
We found that the effects of temperature on P. japonica growth and consumption rates varied widely among plants species: increased temperatures stimulated growth on some plants and decreased growth on others. The differences in growth among plant species are attributable to plant nutritional quality. At low temperatures, plant nutritional content did not affect beetle growth. At high temperatures, beetles grew best on plants with high nitrogen and carbon content, perhaps reflecting increased demand for nitrogen-rich materials or carbohydrates.
Additionally, by extracting plant secondary chemicals, we found that temperature reorganizes beetle feeding preferences by altering the effects of plant chemical defenses. Interestingly, the plants that beetles preferred at high temperatures were not the plants on which beetles grew best, indicating that the beetles were making decisions that may not lead to optimal growth rates.
Our results indicate that direct effects of temperature on herbivore physiology can possibly re-organize the intensity of herbivory among plant species and that these changes can be predicted based on plant nutritional quality. These changes will become more important in the future as the climate warms.