Table 2 Prevalence of the larval trematodes (% infected snails in the pooled samples) in the two hosts studied in the four Ruhr reservoirs and significance of differences (p) for between-reservoir comparisons (contrasts in overall prevalence and the prevalence of the dominant species).

Diplostomum spathaceum*

GUL

0.59

5.64 (1)

-

4.55

0.027

-

-

-

-

-

Trichobilharzia franki*

ANA

0.59

8.72 (2)

-

-

0.0001

-

-

-

-

-

Paryphostomum radiatum*

COR

3.55 (1)

4.10 (1)

-

-

ns

-

-

-

-

-

Echinoparyphium recurvatum*

ANA

11.24 (3)

4.10 (1)

-

-

0.007

1.48

-

-

-

-

Opisthioglyphe ranae*

AM

1.18 (1)

-

-

2.27

ns

-

-

-

6.25

-

Plagiorchis elegans

VAR

-

0.51

4.55

-

-

0.74

-

-

-

-

Australapatemon burti

ANA

-

1.03

-

-

-

-

-

-

-

-

Echinostoma sp.

ANA

0.59

1.54

-

-

-

-

-

-

-

-

Hypoderaeum conoideum

ANA

-

1.03

-

-

-

-

-

-

-

-

Isthmiophora melis

MAM

-

1.03

-

-

-

-

-

-

-

-

Notocotylus attenuatus

ANA

0.59

0.51

-

-

-

-

-

-

-

-

Tylodelphys clavata

GRE

-

1.03

-

-

-

-

-

-

-

-

Diplostomum pseudospathaceum*

GUL

-

-

-

-

-

3.70

9.10

17.39 (1)

12.50

0.036

Echinostoma revolutum

ANA

-

-

-

-

-

5.19

-

4.35

-

-

Trichobilharzia szidati

ANA

-

-

-

-

-

2.96

-

-

-

-

Overall prevalence (%)

18.3

28.2^a

4.6

4.6^b

0.0001

14.1

9.1

21.7

18.8

ns

No. of species in component communities (range)

1-4

1-7

1

-

-

1-2

-

2

-

-

No. of dominant species in component communities (range)

0-2

0-3

-

-

-

-

-

1

-

-