Common Name: Arizona stink bug; Dendrocoris stink bug
Scientific Name: Dendrocoris arizonensis (Barber, 1911)
Global Status (2001): G4
National Status (United States): NNR
State Status: Oregon (S2).
Dendrocoris arizonensis is a terrestrial bug in the family Pentatomidae (stink bugs). This is the third largest family of true bugs, with around 200 species in North America and 4,100 species worldwide (Marshall 2006). As the name implies, stink bugs are known for the disagreeable odor they emit, particularly upon disturbance. (Other bugs also produce foul odors, but the stink bugs are the most common and abundant of the odor producing bugs.) (Triplehorn & Johnson 2005). In addition to their characteristic pungency, members of this family are easily recognized by their distinctive (broadly ovoid) shape and 5-segmented antennae. They can be separated from other heteropteran families with 5-segmented antennae by their relatively large size (usually over 8 mm), 3-segmented tarsi, and scutellum not greatly enlarged, i.e., not covering most of the abdomen (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.
The genus Dendrocoris is comprised of 14 species of relatively small, cryptically colored stink bugs in the plant-feeding subfamily Pentatominae, tribe Procleticini (Thomas & Brailovsky 1999). This genus can be distinguished using the key to the Procleticini by Rider (1994). In summary, Dendrocoris is distinct in the following combination of characters: the presence of a tubercle at the base of the abdomen (absent in some males); scent gland ostioles with elongate rugae (ridges); bucculae (structures between rostrum and head) truncate posteriorly; meso- and metasternum concave, unarmed; juga (lateral lobes of head) contiguous before the tylus; and the female gonocoxites reduced in size (Thomas & Brailovsky 1999). The form of the body is generally depressed, and rounded to oval in outline (Thomas & Brailovsky 1999).
Like others in the genus, Dendrocoris arizonensis is a relatively small stink bug, with a length of 6.6-7.5 mm (male), 7.4-9.25 mm (female), and a width of 3.9-4.5 mm (male), 4.3-5.5 mm (female) (Nelson 1955, Barber 1911). This species is diagnosed as follows (Thomas & Brailovsky 1999):
Vertex of head flat. Juga contiguous before tylus. Cicatrices concolorous with pronotal disk. Anterolateral pronotal margins straight to nearly straight in dorsal view. Humeral angles prominent. Abdominal tubercle present in both sexes but very small in males. Legs immaculate. Abdominal spiracles variable, typically concolorous with venter or occasionally darkened. Veins of hemelytral membrane simple or furcate, not reticulate. Posterior aspect of male pygophore without teeth attending medial emargination. Paramere terminating in long ental and short ectal digit (Thomas & Brailovsky 1999).
See Nelson (1955) for a full description of Dendrocoris arizonensis including descriptions and illustrations of the male and female genitalia. Barber (1911) provides the original description of this species and a key to the seven Dendrocoris species known at that time. A more recent key to the 14 species currently known is provided by Thomas & Brailovsky (1999), along with an illustration of the male paramere.
Immature: Stink bug (Pentatomidae) nymphs lack the fully developed hemelytra of adults, but can be recognized by many of the same features as the adults (e.g., characteristic shape, 5-segmented antennae, 3-segmented tarsi). The nymphal stage of this species has not been described.
Egg: Stink bug eggs are usually brightly colored and barrel-shaped, with the upper end ornamented with spines (Triplehorn & Johnson 2005). The eggs of this species have not been documented or described.
Approximately one-third of all stink bugs are predacious and the remaining two-thirds are phytophagous (plant feeding) (Marshall 2006). Dendrocoris is a phytophagous genus whose members are associated with the foliage of pine or oak (Applegarth 1995, Thomas & Brailovsky 1999). Dendrocoris arizonensis is associated with oak (Quercus), particularly oak foliage (Applegarth 1995, Nelson 1955). Given this association, it is likely that D. arizonensis feeds on oak foliage, probably in both the nymph and adult stages. Apart from its association with oak, little is known about the biology of this species (Nelson 1955).
In general, stink bugs are well-known to release defensive chemicals from their scent glands in an effort to deter would-be predators. Some stink bugs also use their scent glands to secrete compounds that inhibit microorganisms, and to attract mates (Marshall 2006). Following mating, stink bug eggs are usually laid in groups, lined up side by side (Triplehorn & Johnson 2005).
The phenology of this species is not well known. Applegarth (1995) reports that this species overwinters in the adult stage, and that most collections of have been made during spring and fall months. In Oregon, known records are from April, May, July, October, and November (OSAC 2013, LaBonte 2013, pers. comm.).
Range, Distribution, and Abundance:
The distribution of this species ranges from Mexico through the southwestern United States, north to Oregon. In Mexico, it occurs in Nuevo Leon, San Luis Potosi, and Durango (Thomas & Brailovsky 1999). In the United States, it is documented from New Mexico, Arizona, Texas, California (Thomas & Brailovsky 1999), Colorado (Nelson 1955), and Oregon (Applegarth 1995).
This species is rare in Oregon, with less than 10 known records in two disjunct regions: Benton County (Corvallis area) and Jackson County (Medford/Ashland area) (Applegarth 1995; OSAC collection data 2013). Oregon appears to be at the northernmost part of this species range (LaBonte 2013, pers. comm.).
BLM/Forest Service lands: This species is Suspected on BLM land in the Medford and Salem Districts, based on close proximity to known records (see maps in Appendix). The Eugene BLM District and the Klamath Falls Resource Area of the Lakeview BLM District both also suspect the species.
In the southwestern U.S. and Mexico, this species is “widespread but limited to mountain habitats surrounded by desert” (Thomas & Brailovsky 1999). In Oregon, Applegarth (1995) lists the habitat as woodlands with oak (Quercus) and other “dry site” trees (Applegarth 1995). Known sites in Oregon range in elevation from 160 to 853 m (525 to 2800 ft.) (OSAC 2013).
Rangewide, the majority of records are from oak, including Quercus argifolia (a California-endemic) at one site in California (Nelson 1955, OSAC 2013). Oak foliage, specifically, appears to be the most common microhabitat (Applegarth 1995, Nelson 1955). In addition to records from oak foliage, there is a California record from an oak gall, an Oregon record collected inside of a house (OSAC 2013), and an Oregon record from Ceanothus cuneatus (a native species of flowering shrub known by the common names buckbrush and wedgeleaf ceanothus) (Lattin 2013, pers. comm.).
Threats to D. arizonensis have not been documented. Given this species’ reliance on oak trees, any loss or alteration of deciduous woodland habitat is expected to be a major threat, particularly in the Willamette Valley where agriculture and development have replaced much of the native forest and prairie habitat. For example, Vesely & Rosenberg (2010) report that native oak and prairie plant communities in the Willamette Valley have declined in area to <10% of their pre-settlement extent; this decline is attributed to conversion to agriculture, urban and suburban development, and succession to dense hardwood or Douglas-fir dominated forest as a result of fire-suppression (Vesely & Rosenberg 2010). Invasive species that limit the establishment of young oak seedlings may also threaten D. arizonensis at some sites.
Inventory: This species is known from very few collections in Oregon, probably due to both rarity and lack of targeted sampling effort. To date, there are less than 10 known records from two disjunct areas of the state: Benton County (Corvallis area) where the species was last detected in 1962, and Jackson County (Medford/Ashland area) where the species was last detected in 1978 (Applegarth 1995; OSAC 2013). Further surveys in both regions are needed to evaluate the current status and habitat use of the species. Surveys on BLM and Forest Service land in the vicinity of known records are recommended, including surveys on Medford BLM land surrounding the Buckhorn Springs site, and surveys on Salem BLM land a few kilometers NW of the Sulphur Springs site.
Management: Protect all known and potential sites from practices that would adversely affect this species’ habitat. Manage known sites to maintain oak trees and to prevent the establishment of invasive species.
Prepared by: Sarah Foltz Jordan, Xerces Society for Invertebrate Conservation
Date: 25 March 2013
Edited by: Sarina Jepsen, Xerces Society for Invertebrate Conservation
Date: 10 April 2013
Final edits by: Rob Huff, Conservation Planning Coordinator, FS/BLM
Date: 22 April 2013
List of pertinent or knowledgeable contacts
Map of known records in Oregon and Washington
Photograph and illustrations of this species
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.
Barber, H.G. 1911. Arrangement of the species of Dendrocoris Bergr., with the descriptions of two new species. Entomological News Philadelphia 22: 268-271.
Henry, T.J. 2009. Biodiversity of Heteroptera. Chapter 10. Pp. 223–263 In: Foottit, R.G.; Adler, P.H. (eds) 2009: Insect Biodiversity: Science and Society. Wiley-Backwell, Oxford, U.K. 656 pp.
LaBonte, James. 2013. Taxonomic and Survey Entomologist, Oregon Dept. of Agriculture. Personal communication with Sarah Foltz Jordan, Xerces Society.
Marshall, S. 2006. Insects: their natural history and diversity: with a photographic guide to insects of eastern North America. Firefly Books, Buffalo, New York. 718 pp.
NatureServe. 2013. “Dendrocoris arizonensis.” 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 21 March 2013).
Nelson, G.H. 1955. A revision of the genus Dendrocoris and its generic relationships (Hemiptera, Pentatomidae). Entomological Society of Washington (Washington, DC), Proceedings 57(2): 49-67.
Oregon State University Arthropod Collection (OSAC). 2013. Specimen data gathered by Ashley Clayton, contractor for the Xerces Society.
Thomas, D. and H. Brailovsky. 1999. Review of the genus Dendrocoris Bergroth with descriptions of new species (Pentatomidae: Heteroptera). Insecta Mundi 13(1-2): 1-9.
Triplehorn, C. and N. Johnson. 2005. Introduction to the Study of Insects. Thomson Brooks/Cole, Belmont, CA. 864 pp.
Vesely, D.G. and D.K. Rosenberg. 2010. Wildlife Conservation in the Willamette Valley’s Remnant Prairies and Oak Habitats: A Research Synthesis. Oregon Wildlife Institute, Corvallis, Oregon. Submitted to: Interagency Special Status Sensitive Species Program U.S. Forest Service / Bureau of Land Management Portland, Oregon.
ATTACHMENT 2: List of pertinent or knowledgeable contacts
John D. Lattin, Professor Emeritus, Oregon State University, Corvallis, Oregon.
Michael Schwartz, Research Affiliate, Insect Biosystematics, Canadian National Collection of Insects.
Thomas Henry, Smithsonian National Museum of Natural History, Washington DC.
ATTACHMENT 3: Maps of known records in Oregon
Known records of Dendrocoris arizonensis in Oregon, relative to BLM and Forest Service lands.
Records of Dendrocoris arizonensis in the Medford District, showing proximity to BLM lands.
Record of Dendrocoris arizonensis in the Ashland area, showing proximity to a large amount of BLM land in the Medford District.
Record of Dendrocoris arizonensis in the Corvallis area, showing proximity to Salem District BLM land.
ATTACHMENT 4: Photograph and illustrations of this species
Dendrocoris arizonensis specimen from Oregon, dorsal view. Photograph by Ashley Clayton for The Xerces Society, used with permission.
Dendrocoris arizonensis female genital segment, shown from a ventral view. Punctation not indicated. Figure from Nelson (1955).
Dendrocoris arizonensis male genital segment, shown from a ventral caudal view. Punctation not indicated. Figure from Nelson (1955).
ATTACHMENT 5: Survey Protocol for this species
The distribution of this species ranges from Mexico through the southwestern United States, north to Oregon. This species is known from very few collections in Oregon, probably due to both rarity and lack of targeted sampling effort. To date, there are less than 10 known records from two disjunct areas of the state: Benton County (Corvallis area) and Jackson County (Medford/Ashland area) (Applegarth 1995; OSAC 2013). Since the species was last detected in Jackson County in 1978 and Benton County in 1962, further surveys are needed to evaluate the current status of the species in both regions (OSAC 2013). Surveys on BLM and Forest Service land in the vicinity of known records are recommended, including surveys on Medford BLM land surrounding the Buckhorn Springs site, and surveys on Salem BLM land a few kilometers NW of the Sulphur Springs site.
Surveys in Oregon should focus on woodland sites with oak (Quercus) and other “dry site” trees (Applegarth 1995). Rangewide, the majority of records are from oak (Nelson 1955, OSAC 2013). Oak foliage, in particular, appears to be the most common microhabitat (Applegarth 1995, Nelson 1955). In addition, there is one California record from an oak gall, an Oregon record collected inside of a house (OSAC 2013), and an Oregon record from Ceanothus cuneatus (a native species of flowering shrub known by the common names buckbrush and wedgeleaf ceanothus) (Lattin 2013, pers. comm.).
Spring and fall are the appropriate survey times for this species (Applegarth 1995). In Oregon, known records are from April, May, July, October, and November (OSAC 2013, LaBonte 2013, pers. comm.). This species overwinters in the adult stage (Applegarth 1995).
As a whole, the genus Dendrocoris is most commonly encountered by beating the foliage of the host tree with a stick and collecting any stink bugs that are dislodged (Thomas & Brailovsky 1999). Most specimens of D. arizonensis have been found by beating oak foliage while holding a cloth collecting tray underneath (Applegarth 1995, Nelson 1955). A beating sheet or beating umbrella can serve as an alternative to the cloth tray. In addition to beating foliage, surveyors may wish to collect and visually inspect oak galls for stink bugs, since this species has been found associated with an oak gall on one occasion (OSAC 2013).
After capture, voucher specimens should be placed immediately into a kill jar until they can be pinned. A field catch can also be temporarily or permanently stored in 75% ethyl alcohol, but the alcohol will cause some colors to fade (Triplehorn & Johnson 2005). Adult specimens should be pinned through the scutellum, a little to the right of the midline. 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.), detailed habitat/host plant, and collection method. Complete determination labels include the species name, sex (if known), determiner name, and date determined.
This species is identified using characteristics provided 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. Confirmation of field identifications should be done by taxonomic experts with experience identifying pentatomids.