ORDER: HEMIPTERA (true bugs)
With special reference to aquatic and semiaquatic specimens found in Utah
Diagnosing Features:
Forewings hemelytra
Hind wings membranous
Wings held flat on body with tips crossing apically
Piercing-sucking mouthparts
Antennae fairly long (4-5 segments)
Well-developed compound eyes in most cases
0-2 ocelli
Habitat:
Plants, water, widely distributed
Trophic habits:
Diverse, all suck fluids, many predaceous
Development:
Paurometabolous; wings develop externally on nymphs; adults and nymphs share
the same habitat.
Preservation:
Pinned in scutellum; many small species should be pointed; may also be
preserved in 70% ethanol.
Notes:
Many hemipterans have lateral thoracic scent glands which give off a foul odor.
FAMILY: BELOSTOMATIDAE (giant water bugs)
Photo by CR Nelson
Lethocerus sp.
Morphology:
Largest bug in the order; elongate-oval and dorso-ventrally flattened body;
pair of flat retractile air straps at apex of abdomen; antennae shorter than head
and inserted beneath eyes; eyes slightly projecting; prominent raptorial forelegs;
“toe-biters.”
Ecology:
Climbers and swimmers; lentic and lotic habitats; predators; painful bites.
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Utah genera:
Abedus: tibia and tarsus of middle and hind legs of similar widths, and not
strongly flattened; membranous portion of hemelytra reduced.
A. herberti: common to warm springs in Washington Co.
Belostoma: tibia and tarsus of middle and hind legs of similar widths, and not
strongly flattened; membranous portion of hemelytra not reduced.
B. flumineum: common in ponds in northern Utah.
B. bakeri: reported to occur in desert springs in Millard Co.
Lethocerus: tibia and tarsus of hind legs strongly flattened and noticeably broader
than tibia and tarsus of middle pair of legs; two furrows in patch of setae on inner
side of front femora.
L. griseus: found in ponds in northern Utah, but uncommon.
L. americanus: common in valley ponds; widespread.
FAMILY: CORIXIDAE (water boatmen)
Photo by CR Nelson
Morphology:
Body oval and elongate, somewhat dorso-ventrally flattened; beak
triangular, very short and unsegmented- looks like apex of head; fore tarsi flat,
scoop-like with fringe of stiff setae; natatorial (oar-like) hind legs; pattern on
hemelytra gray or dark green, reticulate, checkered, or banded.
Ecology:
Fully aquatic; swimmers; swim dorsal-side up; mostly predators, some
herbivorous,especially when young; more commonly found in lentic habitats
but also in slow to moderate lotic waters.
Utah genera: (identification difficult)
Graptocorixia: common in ponds; Washington and Kane Cos.
G. abdominalis, G. californica, G. uhleri
Arctocorisa:
A. sutilis: common in ponds and lakes of high mountains of northern Utah.
A. Lawson
Callicorixa: common in ponds, lakes, and streams of valleys and mountains;
widespread. C. alaskensis, C. audeni, C. tetoni, C. vulnerata.
Cenocorixa: common in ponds, lakes and streams of valleys and mountains;
widespread. C. bifida, C. kuiterti, C. sorensoni, C. utahensis, C. wileyae,
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C. andersoni, C. expleta.
Corisella: common in ponds and streams in valleys; widespread.
C. decolor, c. edulis, C. inscripta, C. tarsalis.
Hesperocorixa: abundant in ponds and streams; widespread.
H. laevigata.
Sigara: common in ponds and streams in northern and central Utah.
S. grossolineata, S. nevadensis, S. washingtonensis, S. ornani, S. alternate.
Trichocorixa: found in ponds in northern Utah, but uncommon.
T. verticallis interiors, T. calva, T. uhleri.
FAMILY: GELASTOCORIDAE (toad bugs)
Photo by CR Nelson
Morphology:
Round non-elongate bumpy bodies, somewhat dorso-ventrally flattened;
eyes protruding laterally; raptorial front legs; rostrum short, not extending to hind
coxae; antennae inserted beneath eyes and not visible from dorsal view.
Ecology:
Semiaquatic- found on shores of streams, springs and ponds.
predators; hop (hence the name toad bugs) to catch prey or to escape when
threatened.
Utah genera:
Gelastocoris: beak arising from front of head; front tarsus with two claws in
nymphs and adults; base of fore femur less broad than Nerthra; found on sand and
gravel shores of streams and springs.
G. oculatus oculatus: more common in southern Utah, but also occurs in Salt
Lake Valley.
Nerthra: beak seeming to arise from back of head; front tarsus with single claw in
adults; base of fore femur quite broad and roughly triangular. Found in thick
vegetation or under rocks on shores of slow streams or pools.
N. martini: one occurrence in Washington Co.
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FAMILY: GERRIDAE (water striders)
Photo by CR Nelson
Metrobates sp.
Morphology:
Body usually long and slender; hind legs particularly long (extend far past apex of
abdomen); middle pair of legs also much longer than front pair, which are
particularly short; significant space between insertion of front and middle pairs of
legs; all tarsi two segmented; anteapical claws not modified as a swimming
plume.
Ecology:
Skaters; found most commonly on lentic waters or in pools or backwaters of
lotic waters where the flow is slower; predators.
Utah genera:
Gerris: generally smaller; abundant on surfaces of lakes, ponds and streams;
widespread.
G. buenoi, G. comatus, G. gillettei, G. incurvatus, G. marginatus, g. nyctalis,
G. pingreensis (on high mountain beaver ponds), G. remigis.
Limnoporus: particularly long antennae; on ponds and streams in northern Utah.
L. notabilis
Rheumatobates: short, curved antennae with stiff bristles on third segment.
R. hungerfordi- known from the Green River at Green River.
Metrobates: antennae smaller; first segment of antennae subequal to combined
lenth of last three.
M. trux (known from the White River near Ouray; may also be present on Bear
and Green Rivers.)
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FAMILY: HEBRIDAE (velvet water bugs)
Photo by CR Nelson
Morphology:
Two segmented tarsi with apical claws; short legs; no veins in wing
membrane; deep longitudinal channel for rostrum on ventral surface of head;
males thinner than females; very small.
Ecology:
Skaters and climbers; generally found in littoral zone of lentic waters; predators.
Utah genera:
Hebrus: climbers; found among emergent vascular hydrophytes or under rocks in
littoral zone or just on shore; fourth (last) antennal segment with a constriction
that makes it look like two segments.
H. buenoi, H. hubbardi, H. Obscura, H. Sobrinus.
Merragata: skaters and climbers; found in littoral zone on floating algal mats;
short antennae with wide/stout segments.
M. hebroides- known from west desert of Utah.
FAMILY: HYDROMETRIDAE (water measurers)
Photo by CR Nelson
Morphology:
Body elongate and slender; head very long- longer than pronotum and
scutellum combined; long thin legs with apical claws.
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Ecology:
Slow skaters- walk on water’s surface; limnetic, found mostly in littoral zone,
also can be found on slow margins of lotic water; predators- especially favor
Culicid larvae and pupae and ostracods.
Utah genera:
Hydrometra: the only genus of the family; known from Goshen Ponds, Utah Co.
And Lytle Ranch, Washington Co.
FAMILY: MACROVELIIDAE
Photo by CR Nelson
Morphology:
Tarsi 3 segmented; inner margins of eyes arcuate, not converging
anteriorly; no spines on femora as in Mesoveliidae; males thinner than females;
apical claws; small.
Ecology:
Climbers/sprawlers found in margins of lotic waters; predators.
Utah genera:
Macrovelia: well developed ocelli; pronotum covers scutellum; has only one
species: M. hornii, known from seeps in Davis Gulch near Escalante River.
FAMILY: MESOVELIIDAE (water treaders)
Photo by CR Nelson
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Morphology:
Tarsi 3 segmented; inner margins of eyes converge anteriorly; femora have
1-2 dorsal, distal black spines; scutellum not covered by pronotum; males thinner
than females; apical claws; small to minute.
Ecology:
Skaters/climbers; found in lentic waters, including salt marshes, among
emergent and floating hydrophytes; predators and scavengers.
Utah genera:
Mesovelia: the only genus of the family;
M. mulsanti- uncommon; known from ponds in the Great Salt Lake Desert,
ponds in Emigration Canyon (elev. 5500’), Huntington Creek and Duchesne
River.
FAMILY: NAUCORIDAE (creeping water bugs)
Photo by CR Nelson
Morphology:
Raptorial front legs with broad femora; slightly convex dorsally; oval shape/
outline of body; no veins in hemelytra; eyes not projecting; no air straps/siphons.
Ecology:
Clingers and swimmers; most common in lotic habitat, but can also be found in
lentic waters; predators.
Utah genera:
Ambrysus: found in lotic and lentic habitat; anterior margin of pronotum is
deeply concave behind interocular space; venter of abdomen pubescent;
A. mormon: common in streams throughout all of Utah.
A. woodburyi: common in streams throughout Virgin River and Colorado Plateau.
Pelocoris: found in Nevada, may occur in extreme western Utah; anterior margin
of pronotum behind interocular space is straight or only slightly concave; inner
margins of eyes converge anteriorly.
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FAMILY: NEPIDAE (water scorpions)
Photo by CR Nelson
Morphology:
Long slender, cylindrical siphon (breathing tube) off apex of abdomen, made of
two non-retractile filaments; antennae short and inserted beneath the eyes- not
visible from dorsal view; raptorial front legs; elongate body; long thin legs.
Ecology:
Climbers, poor swimmers; mostly occur in lotic waters in the margins, but also
may be found in lentic waters (ponds); predators.
Utah genera:
Ranatra fusca: uncommon, but has been found in northern Utah among tangled
vegetation along pond margins.
FAMILY: NOTONECTIDAE (backswimmers)
Photos by CR Nelson
Morphology:
Antennae short and inserted beneath the eyes- not visible from dorsal view; hind
legs natatorial- flattened, oar-like; hind tarsi with inconspicuous claws- appear not
to have any; body more or less cylindrical- not flattened; head narrower than
thorax.
Ecology:
Swimmers, some climbers; swim ventral side up and catch prey caught in the
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surface water tension; may rest at the surface or submerged; found in lotic and
lentic waters in littoral zone and margins.
Utah genera:
Beunoa: antennae with 3 segments; eyes not dorsally contiguous; has been
collected only in Washington Co.
B. margaritacea.
Notonecta: antennae with 4 segments; eyes not dorsally contiguous; known to
practice cannibalism; common in lentic and lotic waters in valleys and mountains;
widespread in Utah;
N. indica, N. irrorata, N. kirbyi, N. spinosa, N. lobata, N. undulata, N. unifasciata
unifasciata/andersoni.
FAMILY: OCHTERIDAE (velvet shore bugs)
Photo by CR Nelson
Morphology:
Adults velvet brown with blue spangles; antennae short and inserted beneath the
eyes, but the tips are visible from dorsal view; front legs not raptorial; rostrum
long, extending to or past hind coxae; body oval shaped and dorso-ventrally
flattened.
Ecology:
Semiaquatic; climbers or clingers; occur in lentic and lotic habitat on the
shore/margins among vascular vegetation or on seeps on rock surfaces; collected
by splashing water up onto shore and watching for them to crawl back; not as fast
as saldids; predators.
Utah genera:
Octherus: the only genus of the family.
O. barberi: endemic to the Colorado River drainage; collected on Beaver Dam
Wash at Virgin River Springs, Washington Co.
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FAMILY: PLEIDAE (pygmy backswimmers)
Photo by CR Nelson
Morphology:
Body shape oval and fairly cylindrical; all legs similar- none natatorial; less than
3 mm long; two well-developed claws on hind tarsi; antennae short and inserted
beneath the eyes.
Ecology:
Swimmers/climbers; also swim ventral side up; occur in lentic habitat, especially
in dense stands of emergent (vascular) vegetation; predators- particularly favor
microcrustacea.
Utah genera:
Neoplea: one of only two genera; fore tarsi two-segmented.
N. striola: may occur in northern Utah.
FAMILY: SALDIDAE (shore bugs)
Photo by CR Nelson
Morphology:
Membrane of wing with 4-5 distinct closed elongate cells; hind coxae
broad, lie traverse across abdomen; antennae long, inserted forward of eyes, and
visible from any view; constriction behind head.
Ecology:
Semiaquatic; climbers or clingers; found among emergent vegetation in littoral
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zone of lentic waters or on the shore of lotic waters; predators and scavengers,
specialize on dipteran larvae.
Utah genera:
Pentacora: widespread; occurs on freshwater and marine beaches.
P. sphacelata: reported from the shore of Great Salt Lake.
Lampracantia: genus of only one species.
L. crassicornis: found in northern marshy mountain meadows.
Micracanthia: widespread; also found in marshy meadows.
M. humilis, M. fennica, M. bergrothi, M. quadrimaculata, M. utahensis
Salda: widespread; freshwater beaches and marshy meadows.
S. provancheri. S. buenoi, S. obscura, S. coloradensis.
Ioscytus: found alkaline marshes and springs, and margins of lotic waters.
I. politus, I. cobbeni: southeastern Utah, Colorado Plateau.
Saldula: widespread; found in lentic and lotic habitat, including salt marshes.
S. dispersa, S. nigrita, S. balli, S. explanatus, S. opacula, S. pallipes, S. varionis,
S. azteca, S. andrei, S. comatula, S. saltatoria, S. opiparia, S. bouchervillei,
S. severini, S. pexa.
FAMILY: VELIIDAE (broad shouldered water striders)
Photos by CR Nelson
Rhagovelia sp.
Microvelia sp.
Morphology:
Antennae long, inserted forward of eyes and visible from any view; claws inserted
below apex of tarsi; legs shorter than in gerrids- do not extend beyond apex of
abdomen; males thinner than females.
Ecology:
Skaters; lentic and lotic habitats- on water’s surface at edges of streams, rivers
seeps and ponds; predators and scavengers.
Utah genera:
Microvelia: widespread; tarsal formula 1:2:2.
M. Americana, M. hinei: known from southern Utah.
M. pulchella, M. signata: known from seeps in caves at Hoven Weep National
Monument. M. torquata: from seeps in Escalante River, Glen Canyon area.
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Rhagovelia: claws of middle tarsi modified with plumose hairs for swimming;
R. distincta
Phylogeny of aquatic Hemiptera. Merritt, Cummins and Berg, 2008. p. 147
Literature Cited:
Beck, E. 1936. Report on collection of water striders in Brigham Young
University entomological collection. Utah Academy of Sciences, Arts and Letters
13: 203-206.
Merritt, R. W., K. W. Cummins, and M. B. Berg. 2008. An Introduction to the
Aquatic Insects of North America, 4th edition. Kendall/Hunt Publishing Co., Dubuque,
Iowa. pp. 385-423.
Stevens, L. E., and J. T. Polhemus. 2008. Biogeography of aquatic and
semiaquatic heteoptera in the Grand Canyon ecoregion, southwestern USA. Monographs
of the Western North American Naturalist 4: 38-76.
Editorial History:
Pre-2006: Class handouts of Edmunds and Nelson
2006, 25 October: Nelson and Price: compilation of previous materials
2008: Waites: addition of images, more detailed identification information, and literature
cited.
Needs: more information on distribution of genera, and illustrations of specific features
important in ID
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