Seasonal Periodicity of Three Species of Caryophyllaeid Cestodes in the Creek Chubsucker, Erimyzon oblongus (Mitchill), in North Carolina

Abstract

One hundred and seventy-two specimens of Erimyzon oblongus from Lake Raleigh, North Carolina, were examined for caryophyllaeid cestodes from December 1972 to July 1974. Monobothrium ulmeri, Biacetabulum meridianum, and an undescribed species of Penarchigetes were recovered from the "stomach," "pyloric bend," and the first loop of the small intestine of the suckers. Infections of M. ulmeri were limited to an 8-month period and were seasonally periodic in prevalence, mean intensity, maturation, and length distribution. A "temperature dependeant rejection response" is discussed as a possible factor involved in the periodicity of this species. The maturation of M. ulmeri corresponded closely to the host's reproductive cycle, and may have been affected by changes in the host's hormonal levels during the spring. Infections of R. meridianum were present throughout the year, and exhibited a seasonal periodicity in prevalence, maturation, and length distribution. The mean intensity of infection suggests that the establishment of this species is inhibited by heavy burdens of M. ulmeri. Penarchigetes sp. was nonseasonal in prevalence, mean intensity, and maturation. The continuous availability of infective procercoids and the lack of a sucker "rejection response" are discussed as possible explanations for this destribution. Unlike B. meridianum and Penarchigetes sp., the mean intensity of M. ulmeri showed a close relationship with host sex.