Question

Monarch butterfly escapes from predators by:
A. Foul smell
B. Bitter taste
C. Colour combination
D. Rough skin

Answer 1

Hint: The monarch butterfly feeds on the milkweed plant during its larval stage. The monarch stores a poison called cardenolides or cardiac glycosides that it gets from the plant it eats.

Complete answer: The monarch butterfly uses two self-defence mechanisms against vertebrates. The first mechanism is warning colouration in which the butterfly uses bright colours as a warning sign for the predators. Best warning colouration is also known as aposematic colouration.
This mechanism of self-defence keeps the predators away, however it does not necessarily prevent the butterfly from being killed in case the predator attacks. In order to get killed the butterfly uses the second method of self-defence. This method is called toxicity. The butterfly is known to lay eggs on the milkweed plant, hence the caterpillars ingest chemicals known as cardenolides as they grow. The larvae hold on to this chemical until the later stages of their lives. Therefore, if a Predator attacks and bites the butterfly, it ingests the chemical which makes the predator sick after the very first bite. The butterfly is then able to escape The Predator without being killed. Cardenolides are a type of toxic steroids which are cardiac-active. These are found in plants belonging to Asclepiadaceae and Apocynaceae.
Hence, the correct answer is option B.

Note: The toxin may not have a similar effect on invertebrates, hence, invertebrate predators play an important role in controlling monarch population size. It is one of the most recognizable and well-studied butterflies on the planet. Its orange wings are laced with black lines and bordered with white dots.