Classification
There are 5 infraorders:
- Bostrichiformia — including furniture beetles and skin beetles.
- Cucujiformia — includes lady beetles, longhorn beetles, weevils, checkered beetles and leaf beetles.
- Elateriformia — includes click beetles and fireflies
- Scarabaeiformia — includes scarab beetles and stag beetles.
- Staphyliniformia — includes rove beetles and water scavenger beetles.
The internal classification of Polyphaga involves several superfamilies or series, whose constituents are relatively stable, although some smaller families (whose rank even is disputed) are allocated to different clades by different authors. Large superfamilies include Hydrophiloidea, Staphylinoidea, Scarabaeoidea, Buprestoidea, Byrrhoidea, Elateroidea, and Bostrichoidea.
The infraorder Cucujiformia includes the vast majority of phytophagous (plant-eating) beetles, united by cryptonephric Malpighian tubules of the normal type, a cone ommatidium with open rhabdom, and lack of functional spiracles on the eighth abdominal segment. Constituent superfamilies of Cucujiformia are Cleroidea, Cucujoidea, Tenebrionoidea, Chrysomeloidea, and Curculionoidea. Evidently adoption of a phytophagous lifestyle correlates with taxon diversity in beetles, with Cucujiformia, especially weevils (Curculionoidea), forming a major radiation.
Read more about this topic: Polyphaga