ORDER: COLEOPTERA (beetles)
with special reference to those found in Utah
Diagnosing Features, adults:
elytra, which meet at midline (Fig. 1)
highly diverse sizes from less than 1 mm to 125 mm
chewing mouthparts
nearly all lack ocelli
variety of antennal types
Diagnosing Features, larvae:
extreemly diverse forms
typically have a sclerotized head (Fig. 2)
head capsule with mandibles, maxillae, and labium
2-3 segmented antennae
most have three pairs of legs bearing one or two claws
Habitat: Beetles are ubiquitous. Aquatic forms are found in a broad range of environments
including: fast moving mountain streams, the stagnant waters of estuaries, salt marshes, and
rocky intertidal zones.
Trophic Habitat: Extremely variability is noted in the feeding habits of beetles.
Development: holometabolous
Preservation: Adults are pinned through right elytron. Larvae are stored in alcohol.
Notes: Currently the beetles are the most species rich group in the Animal Kingdom. It is the
largest order of insects and includes over 5,000 aquatic species. Although beetles are not
typically dominant species in lotic aquatic environments they are found in a large variety of
aquatic habitats.
Figures:
Figure 1. Elytra meet at midline.
Photo from Invertebrate ID CD.
Figure 2. Sclerotized head.
Photo from Invertebrate ID CD.
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SUBORDER MYXOPHAGA
Diagnosing Features, adults:
peculiar hind wings
usually with 5 stemmata in larva
other features related to hygropetric life: hind coxal plates widely separated
FAMILY: HYDROSCAPHIDAE (skiff beetles)
Morphology (larvae):
Fingerlike lobes present on abdominal segments 1 and 8 only.
Small larvae.
Morphology (adults):
Small, less than 1.5 mm long.
Hind coxal plates widely separated.
Antenna with 8 segments, final segment is as long as previous 4 segments.
Ecology: lives in mats of filamentous green algae where a thin layer of water is running over the
algal mat.
Utah Genera:
Hydroscapha natans
SUBORDER ADEPHAGA
Diagnosing Features, adults:
1st abdominal sternum divided by hind coxae
hind trochanters often large
prothorax with notopleural sutures
nearly always with filiform antennae
tarsal formula 5-5-5
FAMILY: AMPHIZOIDAE (trout-stream beetles)
Morphology (larvae):
Lateral extensions on segments.
No gills.
Morphology (adults):
Oval, dark, 1-1.5 cm. long. (Fig. 3)
Our species with elytral ridges that look like shoulder blades.
Ecology: Larvae predaceous on plecoptera larvae, but remain on land most of the time. Adults
are poor swimmers, generally found clinging to submerged roots and debris, feeding on
plecoptera larvae.
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Utah Genera:
Amphizoa lecontei: uncommon, northern and central Utah.Known from several Wasatch
Front streams, Uinta Mountains, Uinta basin drainage, Raft Rivers. It has
longitudinal elytral ridges.
Figures:
Figure 3. Amphizoa lecontei adult.
Photo from Invertebrate ID CD.
FAMILY: HALIPLIDAE (crawling water beetles)
Morphology (larvae):
Slender, legs with five segments and a single claw.
Morphology (adults):
Hind coxae form large plates which cover the legs.
Small brown beetles.
Head prominent, but small compared to body.
In life they swim madly with alternating motions of the legs.
Ecology: Adults are mostly shredders, some are predators. Larvae are herbivorous.
Utah Genera:
Peltodytes: widespread, common in vegetation in streams, ponds, and lakes. Larvae with
filaments on each body segment half as long as body. (Fig. 4)
Adults with two black spots at posterior margin of pronotum.
Haliplus: widespread, in vegetation in streams and ponds. Larvae with third antennal
segment 2-3 times as long as second.
Adults pronotum with sides widest at base. (Fig. 5)
Brychius: widespread, vegetation in mountain streams. Larvae with third antennal
segment shorter than second. Adult pronotum with parallel sides.
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Figures:
Figure 4. Peltodytes larvae.
Photo from the Invertebrate ID CD.
Figure 5. Haliplus adult.
Photo from the Invertebrate ID CD.
FAMILY: DYTISCIDAE (predaceous diving beetles)
Morphology (larvae):
Usually with long, thin mandibles that look like ice-tongs. (Fig. 6)
Head is more prominent than in Hydrophilidae.
Usually with long, thin cerci-like urogomphi. (Fig. 6)
Morphology (adults):
Swimming beetles with long, filiform antennae – Hydrophilidae have capitate antennae.
Both sets of palps are shorter than antennae.
Usually more dorsoventrally flattened than hydrophilids. (Fig. 7)
Legs with two claws.
Natatorial hind legs.
Ecology: Predators as both larvae and adults.
Utah Genera:
Acilius: small lakes and ponds, widespread, adults large with two black stripes laterally
on pronotum, often with longitudinal ridges on elytra, or lighter markings at
posterior end of elytra.
Agabus: abundant, widespread, all elevations, many species. Adults medium sized, vary.
Dytiscus: common in ponds and slow-moving streams, higher elevations. Larval circus
with lateral fringe, Adults very large, yellow ring around edge of elytra and
pronotum. (Fig. 6)
Laccophilus: ponds and streams, all seasons. Larval urogomphus with numerous
secondary hairs. Adults with scutellum completely hidden.
Rhantus: ponds, margins and pools of streams, larvae with mandible almost three times
as long as broad, Adults in Utah brown with two black spots on pronotum.
Colymbetes: ponds, lakes, and rivers. Mandibles of Larvae shorter, two times as long as
broad. Adults large, with 1-2 stripes on pronotum as in Acilius, but without other
markings on elytra.
Thermonectes: T. marmoratus is common in pools in desert regions of southern Utah,
adult with yellow spots; T. basillaris is rare in northern Utah., all black.
Bidessus: streams and ponds at all altitudes, extremely small.
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Hygrotus: ponds and slow-moving streams, larvae with head narrow, deep notch on
frontal projection.
Hydroporus: pools in streams, ponds and lake margins, widespread but especially in
northern mountains. Larvae with broad head, weak notch on frontal projection.
Small, generally nondescript brown.
Stictotarsus: ponds, springs, and streams at all elevations. Adults small, with patterned
elytra. Very similar to Hydroporus.
Oreodytes: common in fast-flowing rivers and streams, including Provo and Weber
Rivers and many smaller streams. Larvae with long urogomphi. Adults look kind
of like Haliplidae but with broader head.
Figures:
Figure 6. Long urogomphi and tong-like mouthparts.
Photo from Invertebrate ID CD.
Figure 7. Dorsolventrally flattened.
Photo from Invertebrate ID CD.
FAMILY: CARABIDAE (ground beetles)
Morphology (larvae):
9 or 10 abdominal segments.
2 tarsal claws.
Morphology (adults):
Without natatorial hind legs-not flattened and with rows of bristles.
Ecology: Sub-aquatic or littoral. Common on wet sandy banks in southern Utah.
Utah Genera:
Omophron: concealed scutellum. Oval shaped body in adults.
FAMILY: GYRINIDAE (whirligig beetles)
Morphology (larvae):
Long, lateral, filamentous abdominal gills.
2 hooks on abdominal segment 10, and 2-clawed tarsi.
Morphology (adults):
Eyes divided into dorsal and ventral hemispheres. (Fig. 8)
Short antennae.
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Ecology: Larvae are predacious on small aquatic organisms; adults are scavengers of live or
dead insects trapped on the water surface. Often in groups on surface of still or gently flowing
water; widespread.
Utah Genera:
Gyrinus: small, 4-7 mm in length. Elytron have 11 distinct striae. Scutellum is exposed.
Figures:
Figure 8. SEM of split eyes of Gyrinidae.
Photo from C.R. Nelson.
SUBORDER POLYPHAGA
Diagnosing Features, adults:
1st abdominal sternum NOT divided by hind coxae
hind trochanters small
prothorax lacking notopleural sutures
antennae of many types
tarsal formula variable, not always 5-5-5
FAMILY: HYDROPHILIDAE (water scavenger beeltes)
Morphology (larvae):
8 abdominal segments or 10 segments with long urogomphi.
Morphology (adult):
Short clubbed antennae.
Long maxillary palps.
Ecology: Usually scavengers; some predacious; second most specious and abundant family of
aquatic beetles. Found in both streams and ponds and a variety of elevations.
Utah Genera:
Helophorous
Hydrochara
Berosus: elytra are often highly patterned with dark markings on the pronotum. (Fig. 9)
Enochrus
Hydrophilus
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Tropisternus: adults have a longitudinal keel with a long metasternal spine. (Fig. 10)
Hydrobius
Paracymus
Crenitis
Ametor
Helochares
Laccobius
Cymbiodyta
Figures:
Figure 9. Color pattern on Berosus.
Photo from Invertebrate ID CD.
Figure 10. Keel and spine on Tropisternus.
Photo from Invertebrate ID CD.
FAMILY: SCIRTIDAE (marsh beetles)
Morphology (larvae):
Mandibles baring a large, roughened molar lobe.
Without articulated urogomphi.
With multiarticulate antennae that are longer than head.
Abdomen 9 segmented.
Morphology (adults):
6 visible segments.
4th tarsal segment deeply bilobed.
Tarsi 5-5-5.
Ecology: Poorly known; inhabits littoral zones. Only know to have been collected in Utah once
in mosquito pools.
Utah Genera:
Cyphon: Larvae feed on decaying leaves. (Fig. 11)
Pupate hanging freely from submerged objects.
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Figures:
Figure 11. Cyphon larvae.
Photo from C.R. Nelson.
FAMILY: HYDRAENIDAE (minute moss beetles)
Morphology (larvae):
Mandibles baring a large, roughened molar lobe.
Abdominal segment 10 with two recurved ventral hooks.
Morphology (adults):
Antennal club 5-segmented.
6-7 visible sternites.
Ecology: Larvae feed on protozoans and periphyton from leaves and twigs trapped above the
water’s edge. Little is known of the adult life history.
Utah Genera:
Hydraena: reported from Huntington Creek.
FAMILY: DRYOPIDAE (long-toed water beetles)
Morphology (larvae): (Fig. 12)
Terminal abdominal segment is rounded, without a medial notch.
Morphology (adults):
Small with anteriorly expanded prosternum.
Clubbed antennae.
Ecology: Larvae subaquatic or terrestrial; Adult habitats are much as in Elmidae.
Utah Genera:
Helichus: few if any hairs on last abdominal sternite. (Fig. 13)
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Figures:
Figure 12. Dryopidae larvae.
Photo from C.R. Nelson.
Figure 13. Helichus adult.
Photo from C.R. Nelson.
FAMILY: ELMIDAE (riffle beetles)
Morphology (larvae):
Gills or hooks in abdominal opercular chamber.
Terminus of abdomen shallowly notched.
Body quite heavily armored. (Fig. 14)
Morphology (adults):
Small with long legs. (Fig. 15)
Long filiform antennae. (Fig. 15)
Ecology: The efficient gills of the larva and the self-replenishing plastron if the adult allow these
beetles to be among the most truly aquatic; they emerge from the water only to pupate and
disperse. Found among rocks and debris in streams at low, high, and intermediate elevations;
some found in large rivers or lakes.
Utah Genera:
Zaitzevia
Elmis
Narpus
Simsonia
Heterlimnius
Microcylloepus
Optioservus: (Fig. 12)
Cleptelmis
Figures:
Figure 14. Heavy armor on Optioservus larvae.
Photo from Invertebrate ID CD.
Figure 15. Long legs and antenna.
Photo from Invertebrate ID CD.
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FAMILY: LUTROCHIDAE (travertine beetles)
Morphology (larvae):
Similar to Elmids.
Morphology (adults):
Expanded prosternum
Head contacted into thorax concealing antennae and eye.
Ecology: Feed primarily on algae as larvae and adults. Often found around rocks in cool, fast
flowing streams.
Utah Genera:
Lutrochus: (Fig. 16)
Figures:
Figure 16. Lutrochus adult.
Photo from C.R. Nelson.
FAMILY: LIMNICHIDAE (minute marsh-loving beetles)
Morphology (larvae):
2 retractile hooks and 3 tufts of retractile gills in opercular chamber.
Morphology (adults):
Prosternum expanded anteriorly.
Antennae much longer than head but with 10 or fewer segments.
Ecology: Sub-aquatic or littoral.
Utah Genera:
Limnichus: reported from Huntington Creek.
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FAMILY: CHRYSOMELIDAE (leaf beetles)
Morphology (larvae):
Spiracles on abdominal segment 8 forming large dorsal hooks.
Morphology (adults):
Tarsal formula 4-4-4 (with third segment bilobed and concealing the fourth in a notch).
Ecology: Larvae and adults feed on aquatic vascular plants such as water lilies. Common in
ponds with emergent higher plants, especially in mountains; northern and central Utah.
Utah Genera:
Donacia: four species are known from the following counties: (Fig. 17)
D. tuberculifrons – Box Elder
D. subtilis – Uinta and Utah
D. magnigica – Cache, Duchesne, and Utah
D. hirticollis – Daggett, Davis, Iron, Garfield, Sanpete, Summit, Utah, Wasatch,
Uintah, Washington, and Wayne
Plateumaris: eight species are known from the following counties:
P. dubia – Kane, Uintah, and Wasatch
P. flavipes – Cache, Daggett, Duchesne, Garfield, Kane, Sanpete, Summit,
Uintah, and Utah
P. frosti – Salt Lake
P. germari – Beaver, Cache, Daggett, Garfield, Kane, Millard, Sanpete, Summit,
and Utah
P. neomexicana – Box Elder, Cache, Davis, Garfield, Juab, Kane, Rich,
Salt Lake, Summit, Utah, Wasatch, Wayne, and Weber
P. nitida – Box Elder, Cache, Kane, Rich, Uintah, Wasatch, and Weber
P. robusta – Rich and San Juan
P. pusilla – Beaver, Box Elder, Cache, Emery, Garfield, Grand, Iron, Juab, Kane,
Millard, Piute, Salt Lake, Sanpete, Sevier, Summit, Utah, Wasatch,
Washington, Wayne, and Weber
Figures:
Figure 17. Donacia adult.
Photo from C.R. Nelson.
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FAMILY: CURCULIONIDAE (weevils)
Morphology (larvae):
Legless. (Fig. 18)
Morphology (adults):
Usually with a produced rostrum.
Tarsi 4-4-4.
Ecology: Feed on aquatic plants; some are important pests of rice plants. Found crawling on the
bottom of ponds; one species from ponds near Utah Lake
Utah Genera:
Bagous: larvae mine the floating leaves of water lilies – Nymphaea spp.
Figures:
Figure 18. Legless Curculionidae larvae.
Photo from Invertebrate ID CD.
Literature Cited:
Clark, S.M., A.B. Olsen, and M.H. Goodman. 2008. The subfamily Donaciinea in Utah
(Insecta:Coleoptera: Chrysomelidae). Monographs of the Western North American
Naturalist 4:1-37.
Merritt, R.W., K.W. Cummins, and M.B. Berg. 2008. An Introduction to the Aquatic Insects of
North America. Fourth Edition. Kendall/Hunt Publishing Company, Dubuque, Iowa.
p.571-671.
Triplehorn, C.A., and N.F. Johnson, 2005. Borror and Delong’s Introduction to the Study of
Insects. Seventh Edition. Thomson Brooks/Cole, Belmont, CA
Editorial History:
2006: M. Goodman ,Osborne, and C.R. Nelson: compilation of previous materials
2008: A.J. Mitchell: addition of figures, addition of material from Merritt and Cummins 4th
Edition, addition of Chrysomelidae county list from Clark et al., and literature cited section.
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