Question

Monarch butterfly caterpillars are not good to eat because they contain cardiac glycosides (terpenoids). They get these chemicals by ________.

1) Feeding on milkweed plants
2) Feeding on nectar from flowers
3) Feeding on other insects
4) Feeding on leaves from oak trees

Answer 1

Monarch butterfly caterpillars contain cardiac glycosides because they feed on milkweed plants, using the plant's toxins as a defense mechanism against predators.

Step-by-step explanation:

Monarch butterfly caterpillars are not good to eat because they contain cardiac glycosides (terpenoids), which are toxic chemicals that can cause harm if consumed by many potential predators. These caterpillars obtain these chemicals by feeding on milkweed plants. Milkweed contains these toxins, which the caterpillars sequester, allowing them to use the plant's poisons as a defense mechanism.

This evolutionary adaptation ensures that most insect herbivores will avoid eating milkweed due to its poisonous nature, but insects like monarch butterfly larvae have developed the means to detoxify the poison and instead use it to their advantage. Consequently, monarch caterpillars become distasteful or poisonous to their predators, benefiting from the milkweed's defensive chemicals without harming the plant itself.