Scientific name
Order Coleoptera
Similar species
Beetles can be easily mistaken for cockroaches or true bugs. Each group can be easily distinguished by antennae type, mouthparts, and wing position at rest.
| | Beetles | Cockroaches | True bugs |
| Antennae | Segmented antennae | Long, filamentous | Varies |
| Mouthparts | Chewing | Chewing | Piercing-sucking |
| Wing position at rest | Elytra fold flat to create a straight line down the middle of the back | Wings directly overlap on the back. | Wings gently overlap on the back or may appear roof-like |
Diagnostic characteristics
Adults
- Smallest size - 5.5 mm (0.22 in.)
- Largest size - 35mm (1.38 in.)
- Entire body strongly hardened (sclerotized).
- Oval and either large and elongate or short and stout.
- Either monochrome or varicolored body with assorted spot or stripe patterns.
- Chewing mouthparts chewing mouthparts:
mouthparts designed for biting and chewing; mandibles move from side to side with overlapping edges that cut like scissors as well as surfaces for grinding; characteristic of orthopterans <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=head#mouthparts"></a>
that include well-developed mandiblesmandibles:
the jaws of insects with chewing mouthparts
.
- Elbowed (geniculate) to thread-like (filiform) antennae.
- Antennae either uniformly hued or patterned with alternating colored bands.
- Large compound eyes with no ocelli (simple eyes).
- One hardened pair of forewings (elytra) and one pair of membranousmembranous:
with the same character as a membrane, typically used to refer to structures like wings that are clear and translucent like a membrane
hindwings.
- Elytra are posteriorly tapered and either smooth, scaled, or indented.
- Membranous membranous:
with the same character as a membrane, typically used to refer to structures like wings that are clear and translucent like a membrane
hindwings folded beneath the elytra when at rest.
- Closed elytra form a straight line down the middle of the back. Some species have fused elytra and therefore cannot fly.
- Weevils have downward sloping beaks (snouts). Species with well-developed snouts have laterally situated elbowed antennae, a prolonged headhead:
one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
, and reduced mouthparts at the snout tip.
- Weevils with short, poorly-developed snouts have a more rounded headhead:
one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
. - Beetles have unique 'foot' or tarsal formulas since the number of tarsomeres or foot segments in the front, middle, and hind leg vary. Leaf beetles and weevils with a 5-5-5 tarsal formula while long-horned beetles have a 4-4-4 tarsal formula.
Pupae
- Smallest size - 5.8 mm (0.23 in.)
- Largest size - 38 mm (1.5 in.)
- Oval in shape.
- Appendages are free and detached from the pupal case.
- Off-white to yellow color which darkens prior to adult emergenceemergence:
used to describe the completion pupation that culminates in the appearance of the adult form of an insect
. - Lacking mandiblesmandibles:
the jaws of insects with chewing mouthparts
.
- Protective covering structurally similar to adults but with wing padswing pads:
undeveloped or incomplete wing structures that are found on the immature individuals of insects that do not undergo complete metamorphosis, e.g., stink bugs, leaf-footed bugs, grasshoppers
.
Larvae
- Smallest size - 8.5 mm (0.33 in.)
- Largest size - 52 mm (2.0 in.).
- Between 4 - 11 larval instars.
- Larvae are usually grub-like and legless with distinct body segmentation. Some species have a kidney-bean shape.
- Yellow to milky-white body color which darkens before pupation. Some species turn creamy white before maturation.
- Larvae have a round headhead:
one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
with well-developed, dark, chewing mouthparts.
Eggs
- Smallest size - 0.74 mm (0.03 in.)
- Largest size - 5 mm (0.22 in.)
- Many eggs are tiny, smooth, and similar in size to a grain of rice.
- Mostly elongate and cylindrical. Some species are oblong-oval or ovoid. Other species are cylindrical with tapering at both ends.
- Translucent to pale yellow, but darken when ready to hatch.
- Layered egg masses are commonly covered in gelatinous film.
Hosts
Citrus hosts
Several beetles have all citrus species and their hybrids listed as hosts including the cucurbit beetle, Diaprepes root weevil, Fuller rose beetle, little leaf notcher, northern citrus root weevil, and southern citrus root weevil. See individual fact sheets for more detailed information.
Non-citrus hosts
Coleopterans have a broad host rangehost range:
the range of species that a particular organism can feed on to achieve successful growth and reproduction
that includes weeds, vegetables, field, and flower crops. See individual fact sheets for more detailed information.
Host damage
Flowers
Adults may feed on flowers and flower buds.
Fruit
Adults may feed on the fruit and cause distinct scarring.
Leaves
When adults feed, they may create semi-circular to marginal notching on leaves, tender shoots, or petioles that resemble damage caused by caterpillars or grasshoppers. Extensive feeding can lead to defoliation. Gravidgravid:
female that is bearing eggs
female adults commonly lay egg masses on mature leaves.
Roots
Larvae can inflict severe root damage by tunneling or girdlinggirdling:
removal of the bark, phloem, and cambium tissues around the entire circumference of the effected plant part (branch, root, or trunk) that results in the death of the wood beyond that point; characteristic damage inflicted by specific insects like beetle larvae
that can lead to increased susceptibility to secondary infections and stunted growth.
Stems
Gravid gravid:
female that is bearing eggs
female adults may lay sticky egg masses on or near the fruit stem.
Trunk
Gravid gravid:
female that is bearing eggs
female adults deposit eggs under the bark of the trunk.
Twigs
Adults may feed on twigs that can lead to secondary infection under heavy infestation.
Biology
A female may lay several eggs at a time. Egg masses are deposited directly on or close to the host planthost plant:
the plant the provides sustenance for an insect
leaves or fruit. Females can protect the egg masses with a white gelatinous cover or deposit them into well-concealed areas like bark crevices. Eggs hatch dependent upon the moisture level. Grub-like larvae typically burrow underground to feed extensively on roots. About one month later, larvae stop feeding and pupate underground. As adults emerge, they begin feeding on the leaves or flowers. Typically adults can be found feeding in the early morning or late afternoon, leaving scattered excrement on the leaves. Adults are most active during mid-summer months.
