plecopteran vs insect

plecopteran and insect both are nouns.

Word	Noun	Adjective	Verb	Adverb
plecopteran	Yes	No	No	No
insect	Yes	No	No	No

As nouns, insect is a hypernym of plecopteran; that is, insect is a word with a broader meaning than plecopteran:

plecopteran: primitive winged insect with a flattened body; used as bait by fishermen; aquatic gilled larvae are carnivorous and live beneath stones
insect: small air-breathing arthropod

plecopteran (noun)	insect (noun)
primitive winged insect with a flattened body; used as bait by fishermen; aquatic gilled larvae are carnivorous and live beneath stones	small air-breathing arthropod
	a person who has a nasty or unethical character undeserving of respect