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PROC. ENTOMOL. SOC. WASH. 112(1), 2010, pp. 69–80 ORIUS (HETERORIUS) VICINUS (RIBAUT) (HEMIPTERA: HETEROPTERA: ANTHOCORIDAE) IN WESTERN NORTH AMERICA, A CORRECTION OF THE PAST TAMERA M. LEWIS AND JOHN D. LATTIN (TML) USDA-ARS, 5230 Konnowac Pass Rd., Wapato, WA 98951-9651, U.S.A. (e-mail: [email protected]); (JDL) Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, U.S.A. Abstract.—Collection records for the Palearctic flower bug Orius (Heterorius) minutus (Linnaeus) (Heteroptera: Anthocoridae) in western North America date back to 1930. This species can be very similar in appearance to another Palearctic species, Orius (Heterorius) vicinus (Ribaut). Positive identification is made by examination of the genitalia. We now report O. vicinus from western North America. Over 250 specimens belonging to the subgenus Heterorius were examined from collections made between 1930–2008 in western Washington, western Oregon and western British Columbia. These specimens were identified as O. vicinus, suggesting that all previous records of O. minutus in North America are based on misidentifications of O. vicinus. We observe that O. vicinus can have more extensive darkening on the legs than has been reported in the literature, which may have been a factor contributing to confusion of this species with O. minutus. Key Words: introduced species, Orius minutus, misidentification, genitalia DOI: 10.4289.0013-8797.112.1.69 The genus Orius Wolff is global in ic to the Western Hemisphere, do not fit distribution and contains over 70 iden- well into the current classification tified species. These small insects are (Herring 1966, Woodward and Postle found on a variety of plant species, 1986, Herna´ndez and Stonedahl 1999). usually as predators of other arthropods Several species within the subgenus (Pe´ricart 1972). The genus is separated Heterorius Wagner are so similar in into seven subgenera—Orius s. str., external appearance that examination of Dimorphella, Heterorius, Microtrache- the genitalia is required for positive lia, Paraorius, Xylorius, and Trichorius identification (Pe´ricart 1972, Yasunaga (Wagner 1952; Pe´ricart 1972; Yasunaga 1997b). The left paramere in the genus and Miyamoto 1993; Yasunaga 1997a, Orius begins with a basal foot and then c). A revision of the subgenera appears spirals upward to a rather flattened main to be needed, as a number of Orius body which terminates in a cone (or species, including many species endem- lame). In the subgenus Heterorius a curved, sharpened flagellum and a tooth * Accepted by Michael W. Gates (dent) are attached near the base of the 70 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON cone. Species within this subgenus the earliest known specimen collected differ by length of the flagellum, size in 1930 from Seattle. and placement of the tooth, and shape Orius (Heterorius) vicinus (Ribaut) of the cone (Ribaut 1923, Pe´ricart may closely resemble O. minutus. The 1972). Orius (Heterorius) species may sculpture on the pronotum differs in the also be separated by the size, shape and two species, but viewing this feature segmentation of the copulatory tube in can be difficult and requires care with the female (Pe´ricart 1972). lighting. The posterior lobe of the Orius species recorded from the pronotum is finely, closely punctured continental United States and Canada and transversely wrinkled in O. vicinus, include six native species not assigned and coarsely punctured and less wrin- to a subgenus (Herring 1966), and two kled in O. minutus (Ribaut 1923, Palearctic species belonging to the Pe´ricart 1972). Coloration is sometimes subgenus Heterorius. Orius (Hetero- used to separate these two species. Both rius) majusculus (Reuter), was recently species may have entirely pale heme- reported from Ontario, Canada (Henry lytra and legs, or may have dark 2008). Orius minutus (Linnaeus), which markings, but O. minutus is more likely resembles several other Orius (Hetero- than O. vicinus to have darkening on the rius) species, has been recorded from hemelytra (Pe´ricart 1972), and the the western United States and western possible extent of darkening on the legs Canada for more than seven decades. of O. minutus exceeds that of O. vicinus Tonks (1953) was the first to report O. (Ribaut 1923, Pe´ricart 1972). Examina- minutus from North America, based on tion of the genitalia is often necessary specimens collected in southwestern for identification of these species. British Columbia. Anderson (1962) In this study, we present evidence added other records from British Co- that the previous North American lumbia; Seattle and Bothell, Washing- records for O. minutus actually refer ton; and Albany, Oregon. Downes to Orius vicinus. We first report on an (1957) and Anderson (1962) suggested intensive collection of Orius made in that the species had become established the Seattle area during 2007–2008. We in North America by introductions into then summarize results from our exam- the Pacific Northwest. Kelton (1963, ination of other specimens of Orius 1978) and Herring (1966) included O. collected from 1930 to 2007 from minutus in keys to New World Orius British Columbia, Oregon and Wash- after examining specimens from British ington. We compare the North Ameri- Columbia, Oregon, and Washington. can specimens to representatives of O. Henry (1988), Barnes et al. (2000), vicinus and O. minutus collected in Maw et al. (2000), and Scudder and Europe and Asia, and discuss characters Foottit (2005) based their records of O. used to separate the two species. North minutus from North America on these American plant records for O. vicinus earlier literature reports. Lattin et al. are listed. (1989) reviewed the history and geo- MATERIALS AND METHODS graphic distribution of O. minutus in North America. They provided diagno- Abbreviations.—MCAREC, Mid- ses and illustrations of the adult and the Columbia Agricultural Research and 5th instar nymph, reviewed feeding Extension Center, Hood River, Oregon; habits, and reported additional records OSAC, Oregon State Arthropod Collec- from the Pacific Northwest, including tion, Oregon State University, Corvallis, VOLUME 112, NUMBER 1 71 Oregon; PARC, Pacific Agri-Food Re- imens sent to us as O. minutus from search Centre, Agassiz, British Colum- Japan and specimens sent as unidenti- bia, Canada; YARL, Yakima Agricul- fied Orius from Turkey, Thailand, and tural Research Laboratory, USDA-ARS, England that we identified as O. minu- Wapato, Washington. tus or O. vicinus. Source of insects.—Over 200 speci- Examination of genitalia.—Dissec- mens of Orius (Heterorius) were col- tions were done under a stereomicro- lected from trees, shrubs, and herba- scope using insect pins as tools. Before ceous plants at four sites in King dissection, specimens were softened in County, Washington during 2007– hot water. To examine the copulatory 2008. Two sites are urban areas within tube of the female, the distal half of the the cities of Seattle and Issaquah; the abdomen was removed and placed in other two sites are in forested foothills 10% KOH at room temperature for near the towns of Preston and North about three hours, then rinsed and Bend. Each insect was examined under placed in a drop of water on a a stereo microscope at 503 for external microscope slide. The dorsal abdominal features used to help distinguish O. segments and any adhering internal vicinus from O. minutus. These features matter were removed to expose the included punctation of the pronotum, copulatory tube. The copulatory tube darkening of the legs, and dark mark- originates in the intersegmental mem- ings on the hemelytra. The specimens brane between ventral abdominal seg- were uniform in pronotal punctation but ments VII and VIII (Carayon 1972) and variable in extent of dark markings. The is appressed to the interior wall of collection was sorted by sex and by ventral segment VII. The ventral por- presence or absence of darkening on the tion of the abdomen was positioned cuneus and legs. A subset of specimens with the interior wall facing up, covered was then chosen for examination of with a glass slip, and the copulatory genitalia. This subset contained both tube examined under a compound darkened and undarkened representa- microscope at 2003. If excessively tives and included specimens collected cleared, the copulatory tube was dyed from various plant genera. with chlorazol black E suspended in Orius (Heterorius) collected in pre- 70% alcohol. Copulatory tubes of O. vious years and from other sites were vicinus (n ¼ 8, source U.S.A. and also examined. Lattin et al. (1989) Turkey) and O. minutus (n ¼ 8, source suggested the possibility of three sepa- Japan and Thailand) were photographed rate introductions of Orius minutus into at 2003 and measured with digital North America, as records are clustered software. around the localities of Vancouver For examination of the male genita- (British Columbia), Seattle (Washing- lia, the terminal abdominal segments ton) and Portland (Oregon). Represen- were removed and placed on a slide in a tatives were examined from all three drop of water. The paramere was areas. These specimens were found detached and adhering material was housed as O. minutus in collections at teased away from its basal foot. The YARL, OSAC, MCAREC, and PARC. paramere, flattened face upwards, was Finally, Orius collected from Europe floated on a drop of glycerol and and Asia were compared with the North examined under a compound micro- American insects. These included spec- scope at 2003. 72 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON Species identification.—Identifica- as described in the European literature tion was made primarily by the use of for O. vicinus (Ribaut 1923, Pe´ricart Pe´ricart’s key to the Orius of the 1972), and not the coarse punctures western Palearctic (Pe´ricart 1972). We described for O. minutus (Fig. 2). Some also referred to keys and discussion in specimens had the hemelytra and legs Ribaut (1923), Elov (1976), and Bu and colored entirely light yellowish brown; Zheng (2001).

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