The occurrence of Diplostomum spathaceum metacercariae in the freshwater drum, Aplodinotus grunniens

Abstract

1989. The occurrence of Diplostomum spathaceum metacercariae in the freshwater drum, Aplodinotus grunniens. Can. J. Zool. 67: 2853Zool. 67: -2856 Strigeoid metacercariae from the lenses of freshwater drum, Aplodinotus grunniens, were morphometrically analyzed and compared with those of the North American subspecies of Diplostomum spathaceum: Diplostomum spathaceum indistinctum and Diplostomum spathaceum huronense. The metacercariae resembled D. s. indistinctum in mean body length, mean body width, oral sucker size, and holdfast size. Prevalence of infection in drum was 99% and intensity ranged from 0 to 260 worms per fish (mean f SD = 35 + 32). A significant difference (P < 0.05) in mean intensity between male and female fish was observed, with females harboring a greater worm burden (i.e., 43 in females versus 24 in males). Differences in infection intensity between left and right lenses from all fish were not significant (P > 0.05); however, the degree of asymmetry between left and right lenses of individual fish was highly significant (P < 0.005) according to heterogeneity X2 analysis. In this case, neither left nor right lenses were consistently favored. LENO, G. H., et HOLLOWAY, H. L., JR. 1989. The occurrence of Diplostomum spathaceum metacercariae in the freshwater drum, Aplodinotus grunniens. Can. J. Zool. 67 : 2853 -2856. Des mktacercaires strigCoi'des trouvCes dans le cristallin de Malachigans, Aplodinotus grunniens, ont Ct C soumises ?I une analyse morphomCtrique et comparkes aux sous-espkces nord-amCricaines de Diplostomum spathaceum : Diplostomum spathaceum indistinctum et Diplostomum spathaceum huronense. Les mdtacercaires trouvCes ressemblaient ?I D. s. indistinctum par la longueur moyenne, la largeur moyenne, la taille de la ventouse orale et de la ventouse ventrale. Quatre-vingt-dix-neuf pourcent des poissons Ctaient infect& et on pouvait compter de 0 5 260 vers par poisson (moyenne f Ccart type = 35 + 32). I1 y avait une diffkrence significative (P < 0,05) entre le fardeau de parasites des mAles et celui des femelles et ce sont les femelles qui Ctaient le plus affectCes (43 vs. 24). Les diffkrences entre le fardeau de parasites du cristallin gauche et celui du cristallin droit n'ktaient pas significatives (P > 0,05), mais cependant l'importance de 1'asymCtrie entre le cristallin droit et le cristallin gauche de certaine individus Ctait trks significative (P < 0,005) d'aprks une analyse d'hCtCrogCnCitk baske sur le x2. Cette asymCtrie n'affectait cependant pas un cristallin plus que l'autre de facon constante.[Traduit par la revue]

Diplostomum (Austrodiplostomum) compactum (Lutz, 1928) (Platyhelminthes, Digenea) metacercariae in fish from the floodplain of the Upper Paraná River, Brazil

“…The higher intensity of infection can be associated with physiological changes during reproduction and/or sexual differences in the resistance to infection (Leno and Holloway 1989). Male tucunare´s develop a protuberance on the head during reproductive periods, but according to our results, such fact does not seem to increase its susceptibility to the infection of D.…”

Variation in the intraspecific relationship between fish length and intensity of parasitic infection: biological and statistical causes

“…T I. Data used in the meta-analysis of the relationship between fish length and intensity of infection 14, Wickins & Macfarlane (1973); 15, Nie & Kennedy (1991); 16, Muzzall & Whelan (1995); 17, Carvajal et al (1979); 18, Muzzall (1986); 19, Paperna (1974); 20, Measures (1988); 21, Black (1981); 22, Lankester & Smith (1980); 23, Greenwood & Baker (1987); 24, Siddall et al (1994); 25, Leno & Holloway (1989);26, Poulin (1993); 27, James & Poulin (1998); 28, Paradis & Chapleau (1994); 29, Janovy et al…”

Diplostomum spathaceum metacercarial infection and colour change in salmonid fish

“…This is an important finding, since darker coloration is generally assumed to increase the susceptibility of fish to predation by the avian definitive hosts of this parasite (Milinski 1990). Several investigations have been carried out on the distribution of diplostomids in the eyes of fish, usually reporting a significant asymmetrical distribution in less than one third of the individuals (Rau et al 1979;Ching 1985;Leno and Holloway 1989;Graczyk 1991). Our present observations are consistent with these results, as asymmetry was observed in 5.3-14.8% of the fish, but we also examined asymmetry in an ecological context, in terms of the relationship between asymmetry and the colour change ability of the fish.…”

“…Rau et al 1979;Ching 1985;Leno and Holloway 1989;Graczyk 1991), and significant deviations from a symmetrical distribution of metacercariae between the left and right lenses have been pointed out (Rau et al 1979), although the mechanisms generating this asymmetry are controversial (Ratanarat-Brockelman 1974;Rau et al 1979;Graczyk 1991). Since parasite-induced cataract formation is due to metabolic excretions by the parasites and mechanical destruction of the lens structures (Shariff et al 1980), the intensity of cataract and consequent loss of vision are probably increased with increasing parasite burden.…”