Do insects mass noun

No, a mass noun is an uncountable noun; a Word for something that can't be counted, such things as concepts (knowledge) and substances (steel).

A count noun is a noun that can be counted. A count noun has a singular form (a Word for one person, place, or thing) and a plural form (a Word for two or more people, places, or things).

The noun insects is the plural form for the singular noun, insect. The noun insect is a count noun.