Overwintering Population Changes of Pterygodermatites Coloradensis (Nematoda: Rictulariidae) in Kentucky and Ohio

Field studies demonstrated a 21.3% prevalence of Pterygodermatites coloradensis in Peromyscus leucopus and a decreasing mean worm burden during the October to April, 1977-79, study period. Decreasing worm burden may be due to fewer available infested intermediate hosts, the short life span of adult worms, or both. Forest and cave salamanders are probably not effective transfer hosts of P. coloradensis since they contained few encysted spirurid larvae and are unlikely to be eaten by P. leucopus. Mean worm burden (X = 4.4) and prevalence (15.7%) of encysted larvae P. coloradensis increased more significantly with host size than month of the overwintering study period in cave Ceuthophilus spp. OHIO J. SCI. 81(3): 114, 1981 Because of ease of collection, studies on the parasite fauna of Peromyscus leucopus are common. Pterygodermatites ( = Rictularia) coloradensis is a common parasite of P. leucopus, first reported from North Carolina by Harkema (1936). A study in West Virginia reported a 10% infection of Rictularia sp. in 130 stomachs (probably small intestines) of P. I. noveboracensis (Wilson 1945). Tiner (1948) redescribed and reported the occurrence of R. coloradensis using specimens from P. I. leucopus, P. I. noveboracensis (Maryland) and P. m. bairdii (Wisconsin). In central Ohio, Oswald (1956) found 30 of 82 (36.6%) P. I. noveboracensis infected with R. coloradensis. Zenchak and Hall (1971) showed a relatively high prevalence (50.8%) of Pterygodermatites sp. (probably P. coloradensis) in 120 P. leucopus collected in West Virginia from March to November. Hall et al (1955) found a 20.7% and 30.2% prevalence of R. coloradensis in 82 and 53 P. leucopus from Maryland and Kentucky, respectively. Oswald (1958a, 1958b) completed the first rictulariid life cycle in Rictularia coloradensis from P. leucopus and noted that worm burden was largely independ^anuscript received 2 April 1980 and in revised form 23 July 1980 (#80-16). ent of number of ingested larvae, but their number declined with time; 80 days was postulated to be the maximum life span of R. coloradensis in the laboratory mouse. Experimentally, eggs of R. colorandensis were shown to be infective to the orthopterans Parcoblatta pennsylvancia, P. virginica, Blatella germanica, Supella supellectilium, Blatta orientalis, Periplaneta americana, Acheta assimilis, and Ceuthophilus sp., and he demonstrated natural infestations in Ceuthophilus gracilipes, Ceuthophilus sp., and Parcoblatta pennsyhanica. Quentin's (1969) revision of the Rictulariidae recognized two valid genera, Rictularia and Pterygodermatites. Rictularia coloradensis was designated the type species of the subgenus Paucipectines in the genus Pterygodermatites. The primary characteristics on which this classification was based were cephalic morphology, disposition of male cloacal papillae, and number of cuticular spines. The present study was aimed at determining overwintering mechanisms of Pterygodermatites coloradensis by surveying definitive, intermediate, and potential paratenic hosts. MATERIALS AND METHODS White-footed mice, Peromyscus leucopus, were collected from two forest locations in Indian