Michael E. Mongtomery 1, Richard McDonald 2, Laura Schwartzberg 3 1 US Forest Service, Northern Research Station, Hamden, CT; 2 Symbiont, Sugar Grove, NC; 3 South Salem, NY Scymnus (Pullus) coniferarum Crotch 1874 (Coleoptera: Coccinellidae) An Adelgid Predator Native to the Western United States Crotch, GR Revision of the Coccinellidae of the United States. Trans. Am. Entomol. Soc. (Phila.) 4: Gordon, RD The Scymnini (Coleoptera: Coccinellidae) of the United States and Canada: Key to genera and revision of Scymnus, Nephus, and Diomus. Bull. Buffalo Soc. Nat. Sci. 28: Gordon, RD The Coccinellidae (Coleoptera) of America North of Mexico. J. New York Entomol. Soc. 93: Kohler, GR Predators associated with hemlock woolly adelgid (Hemiptera: Adelgidae) infested western hemlock in the Pacific Northwest; 121 pages, Dept. Forest Sci., Oregon State Unviersity Montgomery, ME, Lyon, SM Natural enemies of adelgids in North America: Their prospect for biological control of Adelges tsugae (Homoptera: Adelgidae), pp In SM Salom, TC Tigner, RC Reardon (eds.). Proceedings of the First Hemlock Woolly Adelgid Review, Charlottesville, VA, Oct. 12, USDA Forest Service, FHTET,Morgantown, WV. References Cited The conifer lady beetle, Scymnus coniferarum Crotch, is widely distributed in the western United States. We have collected more than 200 specimens in the Seattle, Washington, metropolitan region from adelgid infested hemlock. We have established a laboratory colony and reared it through a complete generation on the hemlock woolly adelgid. Its biology and host range are being evaluated to assess its potential for biological control of Adelges tsugae in the eastern United States. Summary Occurrence Scymnus coniferarum was previously collected from several western U.S. states and from British Columbia (Fig. 4). The majority of collections were in California. Table 1. Relative number of Laricobius nigrinus (Ln) and Scymnus coniferarum (Scw) collected from western hemlock in the Seattle, Washington, metropolitan area. ScwLnSiteDate 2115Seig Hall, University of Washington26-Oct Ft. Lawton15-Nov Total 145Discovery Park23-Oct Ft. Lawton23 –Oct Marymoor, Bellevue23-Oct Salt Hood, Seattle22-Oct Firecrest21-Oct Washington Park Arboretum19-Oct Discovery Park16-Oct-08 9Washington Park Arboretum11-May-08 24Chittenden Locks11-May-08 10Washington Park Arboretum10-May Chittenden Locks04-Apr Ft. Lawton26-Feb-08 Figure 1. Scymnus (Pullus) coniferarum. Photo by Nathan Havill. The lady beetle genus Scymnus has more than one hundred species in the United States, with the majority in the subgenus Pullus. These are small in size, usually less than 3.0 mm with pubescence on the dorsal surface, antennae 11-segmented, and an incomplete postcoxal line. Scymnus (Pullus) coniferarum Crotch (Fig. 1) can be distinguished from the other native lady beetles in the subgenus Pullus by its more elongate shape (length 1.75 mm, width 1.15 mm) and distinctive coloration consisting of black pronotum with antero- lateral angles yellowish brown and a yellowish brown elytron with base, triangular area at scutellum and suture piceous (Gordon 1976). Appearance Figure 2. Scymnus (Pullus) suturalis. Photo by I. Altman Its coloration closely resembles Scymnus (Pullus) suturalis Thunberg (Fig. 2), an introduced species established in the eastern U.S.), but the latter is less elongate and the punctures on the elytron are coarser, separated by slightly less than the diameter of a puncture (Gordon 1985). Lab Rearing Scymnus coniferarum has been relatively easy to rear in the laboratory. At temperatures from 12 to 20° C, it reproduced when A. tsugae on T. canadensis was its food source. The immatures completed development in 34 days on A. tsugae. Adults ate a mean of 8.6 eggs, 2.8 nymphs, and 1.0 adults/24 hr. Oviposition by the females was very sensitive to food quality; those receiving only A. tsugae nymphs did not oviposit. Currently, an F-2 generation is being produced in the laboratory. Its biology, feeding on both pine and hemlock adelgids, are similar to S. suturalis (Montgomery and Lyon 1996). The shape of the male genitalia is a primary character that taxonomists use to identify Scymnus species and the sipho can be used to readily distinguish these two species (Fig. 3). Figure 3. Male genitalia of Scymnus (Pullus) coniferarum and S. (P.) suturalis; (a, b = genitalia; c, d = sipho). Since it has been found in northern Idaho and southern Arizona, its climate range seems to be broad. The type specimens collected in 1874 were from pine and an unpublished thesis by Whitehead stated that large numbers of S. coniferarum were collected from lodgepole pine and Monterey pine infested with woolly adelgid. The extensive survey for predators on hemlock by Kohler (2007) found only a single specimen of S. coniferarum. We collected S. coniferarum from western hemlock, Tsuga heterophylla infested with Adelges tsugae (Table 1). We also sampled fir and western white pine infested with S. coniferarum, but did not recover this lady beetle. Its distribution among trees is patchy, with trees in locations exposed to direct sunlight favored. Figure 4. Collection records of Scymnus (P.) coniferarum based on museum specimens; shaded = general area of many collections with dots showing peripheral localities (from Gordon 1985); red rectangle is area of recent collections in the Seattle area by the authors.