Order Coleoptera - Beetles
This is the largest order in the class Insecta with over 250,000
described species. Obviously, with this many species, there is a
wide range of diversity in this order with respect to size,
morphological characters, biology, and behavior. However, the
order is typically characterized by a pair of elytra (hardened front
wings) and a pair of membranous hind wings. They have chewing
mouthparts that may be slightly modified for various functions and
undergo complete metamorphosis. Beetles occur in nearly every type
of habitat, from the desert to aquatic systems, and feed on various
plant and animal materials.
This is the largest family of insects and more than 3,000 species of
weevils occur in North America. Nearly all weevils are
phytophagous. The weevils are easily recognized by having the head
prolonged into a snout, with chewing mouthparts at the tip of the snout.
They often have elbowed antennae.
Leaf Beetles (Chrysomelidae)
The leaf beetles are phytophagous that are typically oval in shape and
often brightly colored. The antennae are obvious, but typically
less that half as long as the body. Their tarsal formula (number
of tarsomeres on fore, mid, and hind leg) is
apparently 4-4-4, but is actually 5-5-5. They are similar to the longhorned beetles, except that the antennae are typically shorter and
the eyes are not notched.
Lady Beetles (Coccinellidae)
Lady beetles are often recognized by their distinctive coloration and
oval body shape. The head is typically partially or entirely
concealed by the pronotum. Their antennae are short with a three-
to six-segmented club. Their tarsal formula is apparently 3-3-3,
but actually 4-4-4. Most adult and immature lady beetles are
generalist predators and have been implemented in biological control
programs. The adults often overwinter in large aggregations.
Scarab Beetle (Scarabaeidae)
Scarab beetles are relatively stout-bodied beetles that vary greatly in
size. There are about 1,400 scarab species in North America, many
of which cause considerable damage to various plants. The tarsi
are all five-segmented (5-5-5). The antennae have 8-11 segments
and are lamellate, which enable them to hold the segments of the club
tight together or expanded. Common scarabs include the May/June
beetles, masked chafers, and Japanese beetles.
Tiger Beetles (Cicindelidae)
Adults tiger beetles are often metallic with distinctive color patterns.
Their characteristic shape is often used in identifying them. The
head is typically as wide or wider than the pronotum. They have
threadlike antennae and long slender legs. These insects are very
fast and often difficult to collect. Their agility and strong
mandibles make them well-adapted for their predaceous life style.
The endangered Salt Creek Tiger Beetle is a member of this family.
Some authorities place the tiger beetles in the same family as the
ground beetles (Carabidae).
Ground Beetles (Carabidae)
The carabids are similar to the tiger beetles and are sometimes
considered to be in the same family. Ground beetles can be
recognized by having a head that is narrower that the pronotum.
They are usually black and shiny, but a few species are brightly
colored. Like the tiger beetles, they have long slender legs.
Nearly all species are predaceous as larvae and adults
Longhorned Beetles (Cerambycidae)
Longhorned beetles are identified by having antennae that are usually at
least half as long as the body and often longer. The body is
typically cylindrical and elongated. The eyes are often notched
around the antennae. All longhorned beetles are phytophagous,
being primarily wood-boring as larvae and flower-feeding as adults.
The tarsi are similar to the chrysomelids, apparently 4-4-4.
Breaking Entomological News...
- Insect Science major Earl Agpawa (conducting undergraduate research with Joe Louis and Eileen Hebets) was named the 2020 winner of the ESA’s Plant-Insect Ecosystems Undergraduate Student Achievement Award.This is a national award that recognizes outstanding accomplishments in entomology by an undergraduate student working with insect-plant interactions. Congratulations, Earl!
- PhD student Sajjan Grover (mentored by Joe Louis) was named the 2020 winner of the ESA’s Plant-Insect Ecosystems Kenneth and Barbara Starks Plant Resistance to Insects Graduate Student Award. This is a national award recognizing a graduate student for outstanding work in the area of host plant resistance. Congratulations, Sajjan!
- Dr. Joe Louis receives a grant to study resistance in sorghum to fall armyworm
- Check out the Emerald Ash Borer Resource Center, and our Emerald Ash Borer Look-Alike Insects Sheet - Be Sure Before You Treat!