SPECIES FACT SHEET
Common Name: Umbrose seed bug
Scientific Name: Atrazonotus umbrosus (Distant, 1893)
Phylum: Mandibulata
Class: Insecta
Order: Hemiptera
Suborder: Heteroptera
Superfamily: Lygaeoidea
Family: Rhyparochromidae
Tribe: Gonianotini
Conservation Status:
Global Status (2001): G3 - Vulnerable
National Status (United States): NNR
State Status: Oregon (S2)
(NatureServe 2013).
Technical Description:
Atrazonotus umbrosus is a small, black, beetle-like terrestrial hemipteran (true
bug) in the Rhyparochromidae family (dirt-colored seed bugs) (Henry 1997,
Applegarth 1995). The Rhyparochromidae represent the largest family in the
Lygaeoidea (seed bug superfamily), with 54 genera and 163 species in the
Nearctic region, and 372 genera and ~1850 species worldwide (Henry 2009).
Members of this family are mostly dull-colored, ground-dwelling species with
enlarged and spinose fore femora (Triplehorn & Johnson 2005). Like other
heteropterans, the mouthparts are of a unique piercing-sucking type, and the
basal portion of the front wing is thickened and leathery, while the apical
portion is membranous. This family is distinct from other true bugs in the
incomplete, forward-curving abdominal suture between sterna 4 and 5, and the
presence of a trichbothrium (elongate seta) near each eye (Triplehorn &
Johnson 2005, Henry 2009).
This genus Atrazonotus is described as follows (Slater & Ashlock 1966):
Head wider than long, finely punctate or rugose, nearly glabrous except
for several setae at apex of tylus. Pronotum much wider than long,
indistinctly divided into two lobes, not constricted laterally, anterior lobe
one half again length of posterior lobe at midline, anterior lobe obscurely
punctate, posterior lobe with punctures smaller than those of hemelytra,
lateral margin everywhere curved, nowhere straight or constricted, evenly
expanded, not widened between lobes, impuctate, concolorous with disk,
posterior margin evenly emarginated, not sinuately so. Scutellum about
as long as broad, nearly flat, very lightly punctate. Hemelytra with lateral
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margins rather strongly curve, clavus with three straight rows of
punctures plus additional confused punctures between inner two rows,
corium with linear rows of punctures near clavus, becoming confused
posteriorly, disk with scattered punctures, impunctate adjacent to costal
margin. Membrane with veins unbranched and concolorous with dark
disk. Metapleuron with shining area above dull evaporative area greater
in height than height of eye viewed from side. Fore femur with a single
row of spines consisting of one major and several smaller setigerous
spines, in all less than six, fore tibia not at all or but slightly curved.
Aedeagus with simple phallotheca and conjunctiva, but with a pair of
small lateral lobes distally on conjunctiva; vesica with a pair of lateral
three-part lobes basally at the conjuctival fold, dorsally with a pair of
bump-like lobes followed by a pair of short, apically directed lobes that
bear tiny spines, distad of ventral bend vesica continues as a short
tapering tube, then bends dorsally at base of helicoid process, the latter
with two complete turns, followed by two complete turns of the gonoporal
process (Slater & Ashlock 1966).
Atrazonotus umbrosus is the type species of the Atrazonotus genus, and is the
only Atrazonotus species in the Nearctic region. Slater & Ashlock (1966) note
that this species is similar to Malazonotus obrieni in characters of the
aedeagus, but the aedeagus of A. umbrosus differs in possessing a series of
small spines on the dorsal lobes at the base of the vesica.
Immature: The immature stages of this species resemble the adults but lack
the fully developed hemelytra (although wing buds are present in the later
stages).
See Appendix 4 for photographs and illustrations of the nympal and adult
stages of this species.
Life History:
Little is known regarding the life history of A. umbrosus. It is reported to live in
leaf litter where it feeds on seeds (Sweet 1964 in Applegarth 1995), although it
is unclear whether seed-feeding behavior has been observed in this species or
is presumed based on taxonomic placement in the Rhyparochromidae family, a
group comprised of primarily seed feeders (Henry 2009). Most members of this
family feed on post-dispersed (fallen) seeds on the ground, although one genus
(Laryngodus) is largely arboreal, feeding on pre-dispersed seeds in the cones of
its host plant (reviewed in Cassis & Symonds 2012). Most known records of A.
umbrosus are from the ground, leaf-litter, wood-chips, or a pitfall trap,
indicating that ground-dwelling behavior is common in this species.
Additionally, one record from an ultra-violet (UV) light trap suggests that this
species is flight capable and/or can climb high off the ground.
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The front legs of Rhyparochromidae are strikingly modified with enlarged and
spiny femora that give them a raptorial/predaceous appearance despite their
known seed-feeding behavior (Triplehorn & Johnson 2005). This puzzle has
been explained by two hypotheses: that the fore legs are used to grasp and
manipulate seeds along irregular substrates, or that they aid in movement
within enclosed spaces (reviewed in Rodriguez 2000). Recent research by
Rodriguez (2000), however, lends support to a third hypothesis: that the
modified legs of these bugs are used in aggressive interactions. In his study of
Scolopostethus affinis, Rodriguez (2000) found that the fore legs of both sexes
were used in conspecific aggressive interactions (both male-male and malefemale), and that seed handling in this species was managed by the rostrom,
not the legs. The specific use of the spiny front femora in A. umbrosus has not
been examined.
Many aspects of this species biology are unknown, including mating behavior,
oviposition site selection, number of eggs laid, number of molts, development
time, life span, number of generations per year, and overwintering behavior.
Likewise, the phenology of this species has not been determined. Known
records in Oregon and Washington are from January, March, May, June,
September, and October (OSAC 2013, LaBonte 2013, pers. comm.). In
California, it has been collected in August. A small number of records from the
southern and southeastern United States range from April to October
(BugGuide 2013).
Range, Distribution, and Abundance:
Atrazonotus umbrosus is widely distributed across North America. In Canada, it
is documented from Saskatchewan, Manitoba, Ontario, and the Northwest
Territories (Chordas et al. 2011), and unpublished photo-vouchered sightings
are reported from Alberta (BugGuide 2013). In the United States, this species is
documented from Oregon, California, Arizona, Colorado, South Dakota, North
Dakota, Kansas, Oklahoma, Texas, Iowa, Arkansas, Missouri, Louisiana, South
Carolina, Florida, Ohio, Indiana, Illinois, Kentucky, New York, New Jersey,
Pennsylvania, Connecticut, Massachusetts, Rhode Island (Applegarth 1995,
Chordas et al. 2011). Additionally, unpublished records are from Washington
(OSAC 2013, museum specimens), North Carolina (GBIF 2013, record data),
Georgia, and Virginia (BugGuide 2013, photo-vouchers).
In Oregon, this species is known from the Willamette Valley, with records in
Benton County (Corvallis area), Marion County (Salem), and Polk County (near
Independence) (Applegarth 1995, OSAC 2013, LaBonte 2013, pers. comm.). In
Washington, known records are from Clark County (Vancouver) (OSAC 2013).
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BLM/Forest Service lands: This species is suspected on Siuslaw National
Forest and BLM land in the Salem District (based on proximity to known
records).
Habitat Associations:
Applegarth (1995) describes the habitat for this species as woodlands with oak
and other “dry site” trees, noting that the species lives in leaf-litter where it
feeds on seeds. In Oregon and Washington, most known records are from “bark
mulch,” “oak,” and “oak and grass litter” (OSAC 2013). In Oregon and
Washington, most known records are from “bark mulch,” “oak,” and “oak and
grass litter” (OSAC 2013). It has also been collected in a pitfall trap in an
Oregon vineyard (LaBonte 2013, pers. comm.). In Minnesota, this species is
listed as an “uncommon species of [oak] savanna” (Haarstad 2000). It has been
found in a pocket gopher burrow in Arkansas (Chordas et al. 2011), and
walking along the ground in Virginia (BugGuide 2013).
Threats:
Threats to this species have not been documented. Loss and fragmentation of
woodland habitat may impact this species, particularly in the Willamette Valley
where conversion of native habitat to agriculture and development is an
ongoing threat (Applegarth 1995).
Conservation Considerations:
Inventory: This species is known from very few collections in Oregon and
Washington, probably due (at least in part) to a lack of sampling effort. If this
species is determined to be a conservation priority in Oregon, further surveys
may be needed to evaluate the species’ current status and habitat use in the
region. Surveys on BLM and Forest Service land in the vicinity of known
records are recommended.
Management: Protect all known and potential sites from practices that would
adversely affect this species’ seed-producing food-plants or other aspects of its
habitat. Manage known sites to prevent loss and fragmentation of woodland
habitat, and encroachment of exotic vegetation.
Research: Many aspects of this species biology are in need of study, including
mating behavior, oviposition site selection, number of eggs laid, number of
molts, development time, life span, number of generations per year, and
overwintering behavior.
Prepared by: Sarah Foltz Jordan, Xerces Society for Invertebrate Conservation
Date: 13 March 2013
Edited by: Sarina Jepsen, Xerces Society for Invertebrate Conservation
Date: 8 April 2013
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ATTACHMENTS:
(1)
References
(2)
List of pertinent or knowledgeable contacts
(3)
Maps of known records in Oregon and Washington
(4)
Photographs of this species and its host plants
(5)
Survey protocol for this species
ATTACHMENT 1:
References
Applegarth, J.S. 1995. Invertebrates of special status or special concern in the
Eugene district. U.S. Department of the Interior, Bureau of Land Management.
126 pp.
BugGuide. 2013. Atrazonotus umbrosus image database. Available at:
http://bugguide.net/node/view/279305/bgimage (Accessed 12 March 2013).
Cassis, G. and C. Symonds. 2012. Systematic revision and phylogeny of the
Australian myrmecomorphic seed bug genus Daerlac Signoret
(Insecta : Heteroptera : Rhyparochromidae : Udeocorini). Invertebrate
Systematics 26: 41–66.
Chordas, S.W. III, Tumlison, R., Robison, H.W., and J. Kremers. 2011. Twentythree true bug state records for Arkansas, with two for Ohio, U.S.A.. Journal of
the Arkansas Academy of Science 65 (153): 1-7.
Distant, W.L. 1893. Biologia Centrali-Americana, or contributions to the
knowledge of the flora and fauna of Mexico and Central America / Insecta
/Rhynochota / Hemiptera-Heteroptera. 462 pp + 39 plates. [Atrazonotus
umbrosus is named on page 409].
Haarstad, J. 2000. Insects of Cedar Creek, Order Hemiptera, Family Lygaeidae
(seed bugs). Cedar Creek Ecosystem Science Reserve. Available at:
http://www.cedarcreek.umn.edu/insects/ (Accessed 21 Feb 2013).
Henry, T.J. 2009. Biodiversity of the Heteroptera In: Foottit, R.G., Adler, P.H.,
eds. Insect Biodiversity: Science and Society. Oxford, England: Wiley-Blackwell:
223-263.
Henry, T.J. 1997. Phylogenetic analysis of family groups within the Infraorder
Pentatomorpha (Hemiptera: Heteroptera), with emphasis on the Lygaeoidea.
Annals of the Entomological Society of America 90(3): 275-301.
Global Biodiversity Information Facility (GBIF). 2013. Atrazonotus umbrosus
records. Accessed via Discover Life Global Mapper, available at:
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http://www.discoverlife.org/mp/20m?kind=Atrazonotus+umbrosus&guide=Gr
oups_Insecta (Accessed 12 March 2013).
LaBonte, James. 2013. Taxonomic and Survey Entomologist, Oregon Dept. of
Agriculture. Personal communication with Sarah Foltz Jordan, Xerces Society.
NatureServe. 2013. “Atrazonotus umbrosus.” NatureServe Explorer: An online
encyclopedia of life [web application]. Feb. 2009. Version 7.1. NatureServe,
Arlington, Virginia. Data last updated: October 2012. Available at:
www.natureserve.org/explorer (Accessed 11 March 2013).
Oregon State University Arthropod Collection (OSAC). 2013. Specimen data
gathered by Ashley Clayton, contractor for the Xerces Society.
Rodriguez, R.E. 2000. On the fore legs of seed bugs (Heteroptera: Lygaeidae):
aggression and allometric scaling in Scolopostethus affinis Schilling. Journal of
the Kansas Entomological Society 73(1): 6-10.
Slater, J.A. and P.D. Ashlock. 1966. Atrazonotus, a new genus of Gonianotini
from North America (Hemiptera: Lygaeidae). Proceedings of the Entomological
Society of Washington 68:152-156.
Sweet, M.H. 1964. The biology and ecology of the Rhyparochromidae of New
England (Heteroptera: Lygaeidae). Entomologica Americana, new series, 43:1124 (part 1) and 44: 1-201 (part 2).
Triplehorn, C. and N. Johnson. 2005. Introduction to the Study of Insects.
Thomson Brooks/Cole, Belmont, CA. 864pp.
ATTACHMENT 2: List of pertinent or knowledgeable contacts
John D. Lattin, Professor Emeritus, Oregon State University, Corvallis, Oregon.
James LaBonte, Taxonomic and Survey Entomologist, Oregon Dept. of
Agriculture, Salem, Oregon.
Merrill Henry Sweet, Professor Emeritus, Texas A & M University, College
Station, Texas.
Michael Schwartz, Research Affiliate, Insect Biosystematics, Canadian National
Collection of Insects.
Thomas Henry, Smithsonian National Museum of Natural History, Washington
DC.
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ATTACHMENT 3:
Maps of known records in Oregon and Washington
Known records of Atrazonotus umbrosus in Oregon and Washington, relative to
BLM and Forest Service lands.
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Known records of Atrazonotus umbrosus in Benton County Oregon (CorvallisBellfountain area). Map shows proximity to Salem BLM and Siuslaw National
Forest lands.
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ATTACHMENT 4:
Photographs of this species
Atrazonotus umbrosus adult, dorsal view. Photograph by Ashley Clayton for the
Xerces Society, used with permission.
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Atrazonotus umbrosus immature. Photograph by Peter Cristofono, identified by
Merrill Sweet, used with permission.
Atrazonotus umbrosus adult, dorsal view. Illustration from Slater & Ashlock
(1966).
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ATTACHMENT 5:
Survey Protocol for this species
Survey Protocol:
Atrazonotus umbrosus
Where:
Atrazonotus umbrosus is widely distributed across Canada and the United
States. This species is rare in the Pacific Northwest, where it is known only
from a few sites in Benton, Marion, and Clark Counties, Oregon and Clark
County, Washington (OSAC 2013, Applegarth 1995). Surveys on BLM/Forest
Service land are expected to be most promising on Salem District BLM land
and Siuslaw National Forest, in the vicinity of the known sites for this species
(see map in Species Fact Sheet).
Applegarth (1995) notes that oak woodlands are the most promising habitat
type for this species in the region. The habitat is further described as
woodlands with oak and other “dry site” trees (Applegarth 1995). This species
is reported to live in leaf-litter where it feeds on seeds (Sweet 1964). In Oregon
and Washington, most known records are from “bark mulch,” “oak,” and “oak
and grass litter” (OSAC 2013). It has also been collected in a pitfall trap in an
Oregon vineyard (LaBonte 2013, pers. comm.). In Minnesota, this species is
listed as an “uncommon species of [oak] savanna” (Haarstad 2000). It has been
found walking along the ground in Virginia (BugGuide 2013), and in a pocket
gopher burrow in Arkansas (Chordas et al. 2011).
When:
Adults of this species are probably best surveyed for in late spring, but note
that the seasonality of this species is poorly known. Known records in Oregon
and Washington are from January, March, May, June, September, and October
(OSAC 2013, LaBonte 2013, pers. comm.). In California, it has been collected in
August. A small number of records from the southern and southeastern United
States range from April to October (BugGuide 2013).
How:
This species has been collected in a variety of ways including by hand, in a
Berlese funnel sample, in a UV light trap, and in a pitfall trap (Applegarth
1995, OSAC 2013, LaBonte 2013, pers. comm). Berlese trap collection may be
the best way to standardize sampling methods and increase likelihood of
encounter. This method involves placing substrate of interest (e.g., leaf litter or
wood chips) into a Berlese funnel and recovering adults and nymphs from the
extracted material.
After capture, adult voucher specimens should be placed immediately into a
kill jar until pinning. Field collections can also be temporarily stored in 75%
ethyl alcohol, but the alcohol may cause some colors to fade (Triplehorn &
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Johnson 2005). For long term storage, adult specimens should be pointmounted, while juveniles are best preserved in vials containing 75% ethyl
alcohol (Triplehorn & Johnson 2005). Collection labels should include the
following information: date, collector, detailed locality (including geographical
coordinates, mileage from named location, elevation, etc.), and detailed
habitat/host plant. Complete determination labels include the species name,
sex (if known), determiner name, and date determined.
Atrazonotus umbrosus is unique in being the only member of its genus in North
America. Adults and late instar juveniles of this species can be distinguished
from similar seed bugs using the information presented in the Species Fact
Sheet. Field identification is possible by those familiar with heteropteran
taxonomy, and can be accomplished by non-experts who have examined and
become familiar with museum specimens and photographs of this species. All
field identifications should be confirmed by taxonomic experts with experience
identifying hemipterans.
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