Danaus plexippus vs monarch

Danaus plexippus and monarch both are nouns.

Word	Noun	Adjective	Verb	Adverb
Danaus plexippus	Yes	No	No	No
monarch	Yes	No	No	No

As nouns, Danaus plexippus and monarch are synonyms defined as:

Danaus plexippus and monarch: large migratory American butterfly having deep orange wings with black and white markings; the larvae feed on milkweed

Other synonyms of Danaus plexippus include milkweed butterfly, monarch butterfly.

Danaus plexippus (noun)	monarch (noun)
large migratory American butterfly having deep orange wings with black and white markings; the larvae feed on milkweed	large migratory American butterfly having deep orange wings with black and white markings; the larvae feed on milkweed
	a nation's ruler or head of state usually by hereditary right