Host-induced variations in Haematoloechus buttensis (Trematoda: Haematoloechidae)

Abstract

The life cycle of Haematoloechus buttensis was maintained in the laboratory by using the usual natural hosts: Rana pretiosa, Physa nuttalli, and Ischnura perparva. Morphological variations in important taxonomic characters were studied and compared with those found when one of the usual hosts was replaced by a sympatric, but usually uninfected, host. In all, six species of Amphibia, three of Insecta, and three Mollusca were used.The effect of host size, sex, and ambient temperature was also studied using R. pretiosa as definitive host.The most reliable taxonomic characters were determined to be the sucker ratio, egg size of 21-day-old and older worms, position of the testes, and the anterior extent of the extracaecal uterine loops.The unreliability of other characters and their prior use as species-specific features suggests that many of the currently recognized species of Haematoloechus are not valid.

The Morphology and Taxonomy of Leucochloridium (L.) variae Mclntosh (Digenea, Leucochloridiidae) from the Nearctic as Revealed by Light and Scanning Electron Microscopy

“…Studies on intraspecific variations and the subspecific concept have increasingly influenced trematode taxonomy (see e.g. Boddeke 1960;Macko & Busa 1960;Marker & Cheng 1960;Odening 1961;Wright 1962;Mettrick 1963;Feige 1966;Panitz 1966;Grabda-Kazubska 1967;Blankespoor 1974;Palmieri 1975;Kennedy 1980;Scott et al 1980), andBakke (1980) arranged the known reports of L. variae broodsacs into L. variae-American variae forms and L. variae-European perturhaturn forms, and suggested that a polytypic subspecies complex is maybe involved in the most isolated populations. Evolution below species level is characterized by continuity of variation and not by a succession of distinct types.…”

Study of Helminth Parasites of Amphibians by Scanning Electron Microscopy

“…Similarly, variations related to occurrence in a wide range of phylogenetically unrelated hosts, i.e. the cases of generalist helminths could detect possible intraspecific variation related with the host age or diet, previous exposure to the parasite, presence of another parasite and number of specimens present (Chitwood, 1957;Haley, 1962;Kennedy, 1980b;Watertor, 1967).…”

Small Frogs Get Their Worms First: The Role of Nonodonate Arthropods in the Recruitment of Haematoloechus Coloradensis and Haematoloechus Complexus in Newly Metamorphosed Northern Leopard Frogs, Rana Pipiens, and Woodhouse's Toads, Bufo Woodhousii

“…However, all other studies on the life histories of frog lung flukes were conducted on odonates as second intermediate hosts, and it is unclear whether nonodonate arthropod infections were attempted in these studies (Krull, 1930(Krull, , 1933(Krull, , 1934Ingles, 1933;Grabda, 1960;Schell, 1965;Dronen, 1975Dronen, , 1977Dronen, , 1978Bourgat and Kulo, 1979;Kennedy, 1980). Studies by Snyder andJanovy (1994, 1996) on second intermediate host specificity of 4 Nebraska Haematoloechus spp.…”

“…Studies on the life cycles and epizootiology of North American frog lung flukes indicate that, in general, adult frogs become infected by ingesting odonate intermediate hosts (Krull, 1930(Krull, , 1931(Krull, , 1932(Krull, , 1933(Krull, , 1934Ingles, 1933;Schell, 1965;Dronen, 1975;Kennedy, 1980). More recently, studies by Snyder andJanovy (1994, 1996) on 4 common frog lung flukes from Nebraska show that host specificity at the first and second intermediate host level can be variable among these parasite congeners, indicating that life cycles of closely related species could differ in evolutionarily significant ways.…”