Diversity of Insects Insects are the most diverse group of animals. Insects are most diverse in the tropics where the combination of high plant diversity and warm climates provides a great number of microhabitats. In the U.S. and Canada there are 91,000 known species and probably about 67,000 undescribed species. The insects are divided into 32 orders according to morphological and genetic relationships. Most beetles are easily recognized by the hardened elytra that cover and protect their wings and abdomen.
Most beetles are herbivorous or predaceous and live in almost any habitat.
With more than 10,000 species Lepidoptera are the second most diverse group. The adults have scaled wings and their mouthparts are modified for sucking nectar or fruit juices. The larvae have chewingmouthparts and lack legs or antennae. Except for a single predaceous species all caterpillars are herbivorous. Like the beetles, the Hymenoptera vary greatly in body morphology and habitat types.