Patrick M. Muzzall

HELMINTH COMMUNITIES OF GREEN FROGS RANA CLAMITANS LATREILLE, FROM SOUTHWESTERN MICHIGAN

A total of 239 green frogs Rana clamitans, collected between June 3 and August 27, 1998 from 6 locations in southwestern Michigan, was examined for helminths. Of the 26 helminth taxa found, the larval cestode Mesocestoides sp. had the highest mean intensity, followed by the larval trematode Fibricola sp. Of the helminths that mature in frogs, Haematoloechus varioplexus had the highest prevalence and Gorgodera amplicava had the highest mean intensity. Frogs from 118th Pond had the highest species richness (20), mean helminth species richness (5.2), and mean helminth abundance (153.7). Frogs from Constantine East had the highest mean helminth species diversity (0.8778) and evenness (0.6033), followed by frogs from 118th Pond. In all comparisons of mean helminth community species richness, abundance, diversity, and evenness, adult frogs had significantly higher or higher values than did juveniles at each location. Jaccards coefficients of similarity for the helminth communities for location pairs ranged from 0.545 to 0.823. Nine and 2 core helminth taxa occurred at the local and regional levels, respectively. The differences in several helminth community measures in green frogs among locations stress the importance of local ecological conditions on helminth community structure.

Helminth infracommunities of the frogs Rana catesbeiana and Rana clamitans from Turkey Marsh, Michigan.

One hundred twenty-seven bullfrogs, Rana catesbeiana, and 120 green frogs, Rana clamitans, collected in July and August 1987 from Turkey Marsh, Michigan, were examined for helminths. Of the 16 helminth species found, Falcaustra catesbeianae had the highest prevalence and mean intensity in bullfrogs. In green frogs, Megalodiscus temperatus had the highest prevalence and Haematoloechus parviplexus had the highest mean intensity. Taxonomically, 1,030 (30.5%) trematodes and 2,348 (69.5%) nematodes occurred in bullfrogs; 2,874 (96.4%) trematodes, 2 (0.1%) cestodes, and 105 (3.5%) nematodes were found in green frogs. The larger and more aquatic of the 2 hosts, R. catesbeiana, had the highest mean number of helminth species, helminth intensity, diversity, and evenness. Adult frogs of both species had a significantly higher mean number of helminth species than did juveniles. Significant correlations existed between the number of helminth species and frog length. Although the helminth communities of Turkey Marsh frogs are isolationist in character, they are more diverse than other helminth communities studied in amphibians.

Organochlorine insecticides, polychlorinated biphenyls, and metals in water, sediment, and green frogs from southwestern Michigan

In an attempt to explain the etiology of frog deformities and population declines, many possible causative factors have been examined, including the input of synthetic chemicals into aquatic systems, where frogs spend much of their lives, including their entire developmental stages. Deformities in populations of green frogs in wetlands of southwestern Michigan that are influenced by agricultural, urban, or industrial inputs were assessed in this study. Of the 1445 green frogs (Rana clamitans) examined, only four (0.3%) exhibited morphological deformities. This deformity rate is less than the recognized background level of deformities for this species, which is approximately 1%. Concentrations of organochlorine insecticides, polychlorinated biphenyls (PCBs), and metals were determined in water, sediment, frog eggs, tadpoles, and adult green frog tissues. Concentrations of all individual organochlorine insecticides in tissue were less than 6 ng/g, wet wt. Concentrations of sigmaPCBs in tissue did not exceed 100 ng/g, wet wt. Concentrations of toxic metals were less than the limits of detection. Because no significant numbers of green frog deformities were observed in this region, it can be assumed that at these low concentrations, physical malformations in green frogs should not be observed. Significance of study. This study provides information on the incidence of deformities in green frog populations in southwestern Michigan and offers background data on chemical residues in green frogs and their environment.

Helminth infracommunities of the newt, notophthalmus viridescens, from Turkey marsh, Michigan

Totals of 163 adult and 20 larval newts, Notophthalmus viridescens, collected monthly from March through September 1989 from Turkey Marsh, Michigan, were examined for helminths. Bothriocephalus rarus, Telorchis corti, Clinostomum sp., Megalodiscus temperatus, Halipegus sp., Spiroxys sp., and Falcaustra cates- beianae infected newts. The patterns of diversity (measured by Brillouins index), evenness, species richness, and intensity for all helminths, irrespective of their site of infection, were examined in newts. Newts have isolationist helminth infracommunities arising from factors including a simple enteric system, restricted vagility, and being gape mouth limited and ectothermic. Although newts are opportunistic predators with a broad prey base, this appears not to play a major role in structuring the helminth infracommunity. Significant correlations existed between newt length and Brillouins index, evenness, species richness, and helminth intensity. Helminths with indirect life cycles predominate in the depauperate helminth fauna of newts.

Ecology and seasonal abundance of three acanthocephalan species infecting white suckers in SE New Hampshire.

The occurrence and host-parasite relationships of three acanthocephalan species parasitizing white suckers, Catostomus commersoni (Lacepede), from two rivers in southeastern New Hampshire were studied. The mean intensity of Neoechinorhynchus cristatus Lynch 1936 was highest in Oyster River white suckers during fall 1975 and 1976. Conversely, the mean intensity of Pomphorhynchus bul- bocolli Linkins in Van Cleave 1919 was highest in spring and summer 1975, spring 1976, and winter 1976-1977. This seasonal pattern coincided with the movement of large suckers into and out of the Oyster River sampling area, and the subsequent examination of large and small hosts. Octospinifer macilentus Van Cleave 1919 and P. bulbocolli infected a large number of Bellamy River white suckers, and did not exhibit seasonal infection patterns. All three acanthocephalan species occurred in the mid- to posterior intestinal area. Significant correlation coefficients suggested that prevalence and/or mean intensity of 0. macilentus and P. bulbocolli (both localities) increased as did fish length. The prevalence and mean intensity of N. cristatus were highest in fish between 5.0 and 14.9 cm in length. Male and female white suckers had similar prevalences and mean intensities. spectively. Fish were taken to the laboratory alive, measured, sexed, and necropsied within 36 hr of capture. The entire alimentary canal (from the esophagus to the vent) was removed. It was divided into five segments based on percentages of the total length from the anterior end (0-20%, 20-40%, 40- 60%, 60-80%, and 80-100%). These segments are designated 1, 2, 3, 4, and 5, respectively. The po- sition, number, degree of development, and sex of the acanthocephalans recovered from each segment were recorded. The rivers and sampling procedure were described in Muzzall (1980). Acanthocepha- lans were fixed and stained using standard tech- niques. Female Neoechinorhynchus cristatus and Octo- spinifer macilentus were divided into three devel- opmental stages: 1) immature-ovary not fragment- ed; 2) ovarian balls present; and 3) gravid-ovarian balls and eggs present, as well as those with eggs only. Indistinct sperm ducts, approximately 2 mm in length or less, in stained males of both species indicated immaturity. Larger males were consid- ered to be adults. Immature female and male N. cristatus and 0. macilentus were considered to be members of the recruitment portion of the parasite

Parasites of the Slimy Sculpin, Cottus cognatus Richardson, 1836, from Lake Huron, U.S.A.

Abstract One hundred slimy sculpins, Cottus cognatus (Cottidae), collected from Six Fathom Bank Lake Trout Refuge in Lake Huron in June 1995 were examined for parasites. A total of 17 parasite species (3 Digenea, 2 Monogenea, 3 Cestoda, 3 Nematoda, 2 Acanthocephala, 2 Ciliophora, 1 Microspora, and 1 Myxosporea) were found to infect sculpins. Tetracotyle sp. had the highest prevalence, mean intensity, and mean abundance, followed by Diplostomum sp. The most common gastrointestinal helminth species was Echinorhynchus salmonis. Epistylis sp. occurred on the gills of 79 sculpins. The mean parasite species richness ± SD and mean helminth abundance ± SD were 5.4 ± 1.6 and 242.6 ± 264.5, respectively. The mean Brillouins diversity and evenness values were 0.5773 ± 0.1915 and 0.5248 ± 0.1892, respectively. Although the helminth community of slimy sculpins is dominated by larval trematodes that mature in piscivorous birds, it is believed that few slimy sculpins are eaten by birds at this location.

Myxobolus cognati n. sp. (Myxosporea) from the opercular integument of Cottus cognatus (Cottidae) in Lake Michigan

A myxosporean producing aggregations of white pseudocysts in skin covering the posterior margin of the operculum and perioral tissue of Cottus cognatus in Lake Michigan is described as Myxobolus cognati n. sp. (Myxosporea). Histological sections revealed that the parasite develops in vascularized regions of the dermis and with development protrudes beyond the surrounding skin surface. Fixed spores are oval in front view, measure 12.0-14.0 microns long and 9.5-10.5 microns wide, and contain 8-11 filament coils wound tightly and perpendicular to the longitudinal axis of the capsule. Myxobolus cognati resembles Myxobolus rhinichthidis Fantham, Porter and Richardson, 1939 from subepithelial tissue of the operculum of the cyprinid Rhinichthys cataractae. Spores in the 2 species are the same size and shape. However, in contrast to those of M. cognati, spores of M. rhinichthidis have filament coils wound loosely at 45 degrees to the axis of the polar capsule and have no sutural ridge folds.

Prevalence of filarioid nematodes and trypanosomes in American robins and house sparrows, Chicago USA☆

Graphical abstract Highlights ► Co-circulating hematozoan parasites in avian amplification hosts for West Nile virus. ► Hematocrit centrifuge technique for microfilariae and trypanosomes. ► Phylogenetics describe community composition of filarioid nematodes and trypanosomes. ► Parasites have potential for direct or indirect interactions with West Nile virus.

Redescription of Rhabdochona cotti [Nematoda, Rhabdochonidae] from Cottus caeruleomentum [Teleostei, Cottidae] in Maryland, USA, with remarks on the taxonomy of North American Rhabdochona spp.

The nematode Rhabdochona cotti Gustafson, 1949 is redescribed from specimens collected from the intestine of the blue ridge sculpin Cottus caeruleomentum (a new host record), a recently described fish species, from Little Fishing Creek in Maryland, USA. The measurements of these specimens, collected in November 2005, are generally smaller than those reported in the original description of R. cotti, this being probably associated with the nematode’s seasonal maturation cycle or the different host species. As revealed by SEM, the deirids of R. cotti are simple (not bifurcate), in which this species differs from almost all North American congeners. Of these, simple deirids, filamented eggs and a rounded tail tip in females occur only in Rhabdochona longleyi, but it distinctly differs from R. cotti in the smaller number of anterior prostomal teeth (6 vs. 14). Rhabdochona rotundicaudatum is considered a junior synonym of Rhabdochona cascadilla; numerous specimens of the latter were collected from Semotilus atromaculatus, Luxilus cornutus and Notropis rubellus from the type locality (Eramosa River, Ontario, Canada) (unpublished). Rhabdochona paxmani and Rhabdochona salmonis are synonymized with Rhabdochona kisutchi, whereas Rhabdochona californiensis is considered a junior synonym of R. cascadilla. The need of a taxonomic revision of North American species of Rhabdochona is stressed.

Ubiquitous variability in the prevalence of Trichobilharzia stagnicolae (schistosomatidae) infecting Stagnicola emarginata in three northern Michigan lakes

During 4 consecutive collecting seasons from 1998 through 2001, 77,326 common beach snails (Stagnicola emarginata, Lymnaeidae) were examined for infections by Trichobilharzia stagnicolae from multiple sites on Walloon Lake, Higgins Lake, and Lake Leelanau, located in the northern region of the lower peninsula of Michigan. Snails were examined for infections using the light-box technique (exposure to bright fluorescent light). The prevalence of infected snails varied significantly among lakes within a year, between years in a lake, at a site from year to year, and at a site over a collecting season. Overall annual prevalence ranged from 0.54% (1999) to 1.32% (2001) on Walloon Lake, from 0.56% (2001) to 1.06% (1998) on Higgins Lake, and 0.30% (2001) to 0.89% (2000) on Lake Leelanau. Generally, the peak in prevalence coincided in July on the lakes. Prevalence was found to increase with snail length in all lakes. A comparison of the light-box technique and crushing snails demonstrated that prevalence varied in magnitude by technique as much as 1.2 and 5.7 times.