SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 117, NUMBER 7 HOST RELATIONSHIPS OF MOTHS OF THE GENERA DEPRESSARIA AND AGONOPTERIX, WITH DESCRIPTIONS OF NEW SPECIES BY J. F. GATES CLARKE U. S. Bureau of Entomology and Plant Quarantine PER\ ^H^^?^ /ORB ••;J5^ (Publication 4083) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION APRIL 23, 1952 ZU ^c>r& (§aitimovt (prcea BALTIMORE, IID., IT. 8. A. — HOST RELATIONSHIPS OF MOTHS OF THE GENERA DEPRESSARIA AND AGONOP- TERIX, WITH DESCRIPTIONS OF NEW SPECIES By J. F. GATES CLARKE U. S. Bureau of Entomology and Plant Quarantine (With Six Plates) In 1932 I began collecting larvae of the species of Depressaria and Agonopterix (Lepidoptera: Oecophoridae) for the purpose of rearing the moths and gaining some knowledge of their habits and distribution and with the hope that unknown species might be dis- covered. It soon became evident that undescribed species of these genera were numerous and that many of their habits were both intriguing and informative. Although interrupted, sometimes for several j^ears, these investigations have continued sporadically over the past two decades with moderate success. During the summer of 1950, by means of a grant-in-aid made by tlie American Philosophical Society which defrayed some of the expense of an extended trip through several western States, I was able to resume my explorations in this field.^ My purpose, essentially, was to determine if possible whether the long-suspected host speci- ficity of many species of Depressaria, particularly those attached to plants of the genus Cicuta, really existed. Unfortunately, only a few species of this genus of plants were found, and so the project was enlarged to include species of moths attached to other umbellif- erous plants. In the course of the summer's field work plants were examined at 80 localities, as shown in the list beginning on page 5. Infestations 1 1 wish to express my gratitude to the American Philosophical Society for the grant-in-aid that made these investigations possible and to the Smithsonian Institution for administering the grant. Also, I have many times been indebted to my friend Dr. Lincoln Constance, Department of Botany, University of California, for determinations of plants and for his stimulating company in the field. During the summer of 1950, in connection with the present studies, I again received his generous help, and again I thank him. I am indebted to Harry F. Clements for furnishing the photograph for plate 5, figure 2; all other photographs and drawings herein are of my own making. Unless other- wise indicated, all material for this paper was collected and reared by me. J. F. G. C. SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 117, NO. 7 2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. II7 do not occur throughout the plants' ranges, the distribution of the moths being affected by other factors. In all, 34 species of umbels were examined. For the most part these food plants were situated along highways and so were readily accessible. I have used this method of roadside collecting for many years and have found that larvae can thereby be collected rapidly and with much saving of time. On the westward journey I made observations and collections at several localities, but it was not until we reached Washington and Oregon that serious collecting really began. A brief discussion of some of the locahties, with illustrations of the habitats and some of the food plants, seems appropriate in order to acquaint the reader with the diverse conditions under which these umbelliferous plants flourish. The Umbelli ferae are found throughout the continent from the seashore to the high altitudes of the Rocky, Cascade, and other moun- tains, in swamps, and in the deserts and prairies. By following the advent of spring from the lowlands to the high altitudes, it is possible to enjoy profitable collecting from March to August. Even in the lowlands of the Midwest and eastern United States and Canada, certain species of larvae will be found well into August. After crossing the Rocky Mountains, going west, one encounters the Intermountain Area between the Rocky and Cascade Mountains. Throughout this inland empire Umbelliferae abound, and it is here that we find a vast number of species of Lomatimn. One species of Lomatium is found as far east as Missouri ; the rest are western. Perhaps the commonest species is L. dissectum, which covers vast areas from Alberta to British Columbia, Montana, Idaho, Washing- ton, and Oregon to Colorado and California. This is host to Depres- saria leptotaeniae. In central Washington and Oregon, desert conditions, which ex- tend north into southern British Columbia and south into California, prevail. In somewhat restricted, sandy habitats within this area will be found Pteryxia terebinthina foeniculacea, the host to D. yakimae (pi. I, figs. I, 2). In Ten Sleep Canyon, Wyo., another variety of this plant, P. t. calcarea, is host to Depressaria pteryxiphaga, described on page 16. Continuing west to the eastern slopes of the Cascade Mountains one encounters a great array and succession of umbelliferous plants that are hosts to a considerable number of species of Depressaria and Agonopterix. One of the commonest species of these plants is Cicuta occidentalis, which is found in marshy areas and along creeks, rivers, and irrigation ditches. On plate 2, figure i, is illustrated a NO. 7 MOTHS, DErRESSARIA AND AGONOPTERIX CLARKE 3 typical habitat at Rock Creek, Oreg., where Oregon State Highway 82 crosses it, in which the Cicufa grows in association with grasses, tule, and Typha. This particular stand of C. occidentalis was heav- ily infested with D. juliella. On plate 2, figure 2, are illustrated unin- fested specimens of this plant at Carlton, Wash. As one leaves the desert and arid spaces of the Intermountain Area and ascends the eastern slopes of the Cascade Mountains he passes through the Timbered Transition Zone. In this zone, usually on the open, rocky slopes, Lomatimn triternatum macrocarpum, host to D. hetina, is found. Also in this zone one encounters Osmorhisa occidentalis and O. chilensis. Both of these species are attacked by Agonopterix rosaciliella, but I have never found a Depressaria at- tached to either of these plants. O. occidentalis is found most abun- dantly at altitudes of 5,000 to 6,000 feet, and 0. chilensis usually grows at lower altitudes and in the Humid Transition Zone of the west side of the Cascades. O. chilensis is not normally infested; in fact, the only infestation I have ever found was at Billy Goat, Okano- gan County, Wash., where the host was attacked by Agonopterix rosaciliella. The alpine meadows, which one encounters after passing through the foothills of the Cascade Range and the high ridges above them, provide the habitats for a great variety of umbels. At Harts Pass, which forms the boundary between Whatcom and Okanogan Coun- ties, Wash., and Slate Peak, in the former county (pi. 3), there are no fewer than twelve species of Umbellif erae. These are : Osmo- rhiza occidentalis, 0. chilensis, Heracleum lanatum, Angelica arguta, Ligusticum purpiireum, Lomatiiim dissectum, L. brandegei, L. geyeri, L. ambigunm, Angelica lyalli Wats., Lomatium gormani (Howell) C. & R., and L. triternatum (Pursh) C. &. R., the last three being recorded by Muenscher." In addition, L. angustatum, from which I have reared D. angustati, will be found on some of the high ridges such as Skyline Ridge, Mount Baker District, Whatcom County, Wash. Proceeding westward, after passing through the alpine meadows and the Arctic Highland ridges, we enter the forested Hudsonian, Canadian, and Humid Transition Zones in that order. In the first two there is little of interest for one devoted to the study of the insects being discussed, but in the Humid Transition there is a wide variety of Umbellif erae. Oenanthe sarmentosa (pi. 5, fig. i), the host of D. nervosa, is 2 Muenscher, W. C, The flora of Whatcom County, State of Washington, pp. 108-110, 1941. 4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. II7 abundant in practically every swale, swamp, marsh, and roadside ditch, and although nervosa is not found throughout the range of the host it is widespread in Oregon and Washington and undoubtedly will be found in British Columbia. I obtained nervosa in quantity on the American side of the international boundary at Blaine, Wash. On the dry prairies of the Humid Transition Zone, on the dry, gravelly slopes of some of the San Juan Islands, and along the sea- shore at Bellingham and Birch Bays, Loniatiitm utriculatum, host to D. besma, and L. nudicaide abound. Shim suave, Cicuta donglasii, and Osmorhisa chilensis are also found abundantly, C. douglasii being an occasional host of D. nervosa. In this zone also Angelica arguta, A. lucida, and A. Iiendersonii are encountered. A. hicida grows in the marshy, tidewater areas of the Siletz River, Oreg., and A. hendersonii (pi. 4, figs. I, 2) is found along the rocky bluffs of the seashore of the Oregon coast. Both of these plants, together with Ligusticum apiifoliuin and Conioselinum chinense, are hosts to A. rosacdiella and A. oregonensis. Throughout all these zones, with the exception of the Arctic, we are apt to find Daucus carota, Heraclewn lanatum, and Conmni maculatwn. H. lanatum is frequently infested with D. heracliana, and the other two sometimes show injury, but I have not yet reared an oecophorid from either one. The species of Depressaria adhere rather closely to a pattern of attack in which the young umbels are webbed by the larva or sev- eral larvae. Pupation takes place in a hollow stalk of the host or in debris at or near the base of the plant. Some exceptional variations are discussed under the pertinent species. On plate 5, figure i, are figured characteristic examples of umbels of Oenanthe sarmentosa in which the rays are drawn together and the inflorescence is distorted by the larvae of Depressaria nervosa.