Final answer:
Herbivores tend to seek out plants with high levels of nitrogen, which they can detect through taste and smell. Nitrogen is an essential element used in the formation of proteins and is thus valuable for herbivores. Some plants produce chemicals that deter feeding or attract specific herbivores that can detoxify plant defenses.
Step-by-step explanation:
Herbivores typically prefer plants with the highest concentrations of nitrogen, an element that is probably detected by taste and odor. This preference is influenced by the chemicals that plants produce, some of which serve as feeding deterrents by being poisonous or signaling that the plant contains poisons. However, certain chemicals attract specific herbivores that may have evolved mechanisms to detoxify these substances. An example would be insects that feed on milkweed, like monarch butterfly larvae, which have adapted to utilize the plant’s toxins for their own defense. Taste, also related to gustation, and smell, or olfaction, are closely linked senses that involve the bonding of molecules to receptors, allowing animals to detect nutrients and potential toxins in their environment. Nitrogen is essential for plants and consequently for herbivores, as it is a key component of amino acids, the building blocks of proteins. Since plants cannot move to escape predation, some have developed tastes and odors that make them less palatable.