What are they?
Beetles (Order: Coleoptera), are the insect group most rich in species, and include ladybugs, weevils, fireflies and, of course, beetles themselves. The order name is derived from the Greek koleos which means sheath, and pteron, wings, i.e. “sheathed wings”.
They are divided into four groups (suborders):
Polyphaga (from poly many, and phago eating) is by far the largest suborder, with approximately 85% of known species, including the fireflies, click beetles, ladybugs, large horned beetles and weevils. They have a very varied diet: They eat plants, fungi, mold, insects and some are parasites.
Adephaga (from adephagos, gluttonous) includes the tiger beetles, earth beetles and aquatic beetles. The majority are predators.
Myxophaga (from myxo fungus or mold, and phago eating) is a small group, with less than 100 species. They are of small size and live in aquatic or interstitial habitats, i.e., they live between grains of sand. They eat mold, fungus and algae.
Archostemata contains five families and around 50 species, many of which are associated with wood (Madison, 2000). This group is considered the most primitive of the beetles.
How many are there?
Worldwide, around 358,000 described species are known, which corresponds to approximately 40% of the total number of insect species, and 30% of all animals (Costa, 2000). They are grouped into 165 families at the global level (Lawrence and Newton, 1995), but for Latin-America, 129 families are known; with 6,704 genera and 72,479 species (Costa, 2000).
In Mexico, 114 families are recognized (Lawrence and Newton, 1995) and the existence of more than 35,500 species of Mexican coleoptera has been estimated (Morón and Valenzuela-González, 1993).