STUDIES on the LIFE HISTORY of RICTULARIA COLORADENSIS HALL, 1916 (NEMATODA: THELAZIIDAE), a PARASITE of Phtomyscus LEUCOPPS NOVEBORACENSIS (FISCHER)

STUDIES ON THE LIFE HISTORY OF RICTULARIA COLORADENSIS HALL, 1916 (NEMATODA: THELAZIIDAE), A PARASITE OF PHtoMYSCUS LEUCOPPS NOVEBORACENSIS (FISCHER) DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio S tate U niversity Bbr VERNON HARVEY OSWALD, B. S ., 11. A. ***** The Ohio State University 1956 Approved by: f Department of Zoology and [ y Entomology ACKNOWLEDGMENTS This study was accomplished through the direct and indirect assistance of many of the faculty members, fellow students, and technical personnel in the Department of Zoology and Entomology of The Ohio State University. The author wishes to thank Dr. Josef N. Knull and Mr. Richard D. Alexander of the Department of Zoology and Entomology for identifying ground beetles and field crickets, respec tively, which were used in th is study. Dr. Edward Thomas of the Ohio State Museum, Columbus, kindly identified wood roaches and camel crickets for the author. Special thanks also go to Mr. Donal (3. Myer for help in collecting material and to Mr. John L. Crites who was concurrently working on the life history of Cruzla americana and who offered many suggestions on techniques which were used by the author. Dr. William H. Coil, a Muellhaupt Scholar in the Depart ment, took an active part in collecting material and is also respon sible for the photomicrographs included in this work. Lastly, the writer wishes to acknowledge the many helpful suggestions and c riti cisms given hy his adviser, Dr. Joseph N. Miller of the Department of Zoology and Entosology. - i i TABLE OF CONTENTS INTRODUCTION ........................................................................................................... 1 HISTORICAL REVIEW................................................................................................. 3 MATERIALS AND METHODS ........................................................................................ 8 CLASSIFICATION.......................................................................................................... 13 OBSERVATIONS AND RESULTS Occurrence of Rlctularia coloradensls in Naturally Infected Mice ............................................................... 16 Experimental Infection of Arthropods............................................... 17 Natural Intermediate H osts............................................................ 22 Development in the Intermediate H ost............................................... 2U Pathology in the Intermediate H ost..................................................... 31 Infectivity of the Larval Stages ......................................................... 33 Development in the Laboratory Mouse ................................................... 35 Pathology in the Definitive H ost....................................................... UU Experimental Infection of other Mammalian Hosts hL Description of the Adult .......................................................................... U7 DISCUSSION General Aspects of the Life Cycle ................................ 51 Taxonomic Considerations.......................................................................... 55 S1WMARY........................................................................................................................ 68 LITERATURE CITED .................................................................................. 71 PLATES ........................................................................................................................ 76 AUTOBIOGRAPHY ............................................................................................................ 90 - i i i - LIST OF TABLES TABLE 1. Incidence of Rictularia coloradensls in Peromyscus leucopus novcboracensls ......................................................................... 16 TABLE 2. Experimental infection of arthropods with Rictularia coloradensls following the feeding of infective eggs............. 19 TABLE 3. Insects examined for natural infections of Rictularia larvae ...................................................................................... 22 TABLE U. Worms recovered from experimentally Infected laboratory mice .......................................................................................... 36 TABLE 5. Comparison of the North American species of R i c t u l a r i a .................................................................. 61 - iv - LIST OF ILLUSTRATIONS TEXT FIGURE 1. Average growth rate of R^ coloradensls In laboratory m ice ...................... ................................................................ 39 TEXT FIGURE 2. Effect of differential growth rates of the esophagus and the prevulvar and postvulvar portions of the body on the relative location of the vulva of R. coloradensls ........................................................................................ U2 TEXT FIGURE 3» Diagrammatic representation of the develop ment of R^ coloradensls in experimental h o sts........................... 52 TEXT FIGURE U. V ariation in the to ta l number of p airs of cuticular processes in male IL coloradensls ............................... 57 TEXT FIGURE 5« Variation in the total number of pairs of cuticular processes in female FL ooloradensls ........................... 57 TEXT FIGURE 6, V ariation in the number of p a irs of prevulvar cuticular processes In female [L coloradensls ........................... 57 TEXT FIGURE 7. Distribution of R^ coloradensls and related North American species of R ictularia............................................. 65 PLATE 1, FIGS, 1-6, The egg and the first and second larval stages of R* coloradensls ...................................* .............................. 77 PLATE 2, FIGS, 7 -13» The third larval stages of R« coloradensls .................................................................. 79 PLATE 3, FIGS, lh-21. The adults of R. coloradensls ............ 81 PLATE Li, FIGS. 22-23. Encysted larvae of IL coloradensls.............. 83 PLATE 5» FIGS. 2h-25. Encysted larvae of R. coloradensls........... 85 PLATE 6, FIGS. 26-27. An immature female and the comb of a mature, female R^ coloradensls........................ 87 PLATE 7» FIGS. 23-29. Spine of an adult, female IL coloradensis and the combs of Rictularia sp. from a wood rat .....89 - v - INTRODUCTION In the following pages, various aspects in the life history of the sp iruroid roundworm, R ictu laria coloradensls H all, 1916, w ill be elucidated. This nematode, originally described from a chipmunk, has been reported from several species and subspecies of white-footed ndce, and it is with material from the latter host that this work is concerned. This study was suggested while the writer was collecting para sites during work on his master's degree. Rhododendron Hollow, located in the extreme northwest corner of Hocking County, Ohio, was found to have a large population of white-footed mice, Peroaorscus leucopus noveboracensls, and the incidence of infection of this host with R^ coloradensls was very high. In any life history study, an abundance of both host and para site material is highly desirable, if not a necessity, for the suc- cussful completion of the work. In this regard, the situation in Rhododendron Hollow was very favorable. The problem also seemed to lend itself well to a laboratory study. In all spiruroid life cycles, an intermediate host, usually an insect, is required. Cockroaches, which are readily reared in the laboratory, are quite frequently suit able as experimental Intermediate hosts for members of this group. It was also anticipated that laboratory mice might serve as experimental definitive hosts for this parasite. This study is of special interest since only one fragmentary life cycle is known in the subfamily to which this parasite belongs. There is also some question regarding the specific status of a number of species in the genus Rictularia, and this work, together with studies on the life cycles of other species in the genus, may eventually solve these problems. HISTORICAL REVIEW Rictularia coloradensls was described by Hall (1916) from one male and an incomplete female specimen obtained from a chipmunk, Eutamlag quadrlvittatus, collected in Pagosa Springs, Colorado. Harkema (1936) rep o rted R^ co lo rad en sls in Peromyscus 1. leucopus from North Carolina, but only female specimens were found. According to Tiner (19U8a), Harkema*s specimens were identified by Dr. B. G. Chitwood. Rankin (19U5) reported IU coloradensls in Eutamias amoenus, Peromyscus maniculatus, and Microtus longicaudus from Northrup Canyon, Washington. Tiner (19U8a) redescribed coloradensls from male and female specimens taken from Peromyscus maniculatus bairdii collected in Wisconsin, a male specimen from P^ leucopus noveboracensis collected at Bowie, Maryland, and Harkema*s North Carolina specimens. The genus R ic tu la ria was erected by F ro e lic h (1802) fo r R. cristata from a dormouse, Muscardinus avellanarius. A large number of species have now been described for this genus; in a review, Dollfus and Desportes (19h5) list a total of thirty-two. In addition to the species listed by these authors, the following have been named: R. nycticebl (MBnnlg, 1920); R._ oligopectinea Wu and Hu, 1938; R» onychomis C uckler, 1939; R^ ondatrae Chandler, 19U1; R^ nana C aballero, 19b3; R^ dlpodonds T iner, 19U8; R^ m icro ti McPherson and T iner, 1952; and R^ baicalensls Spasski, Rishikov, and Sudarlkov,

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