1
Appendix S1. Trematode biomass measurements
2
We obtained direct mass measurements of Ribeiroia ondatrae and Echinostoma
3
trivolvis cercariae by isolating field-collected snails within vials and collecting the free-
4
swimming cercariae using a pipet. We filtered the cercariae onto pre-dried/pre-weighed
5
nylon filters that were weighed with a microbalance (13 filters of 100 cercariae for R.
6
ondatrae and 20 filters of 50, 100 or 200 cercariae for E. trivolvis). Blank filters without
7
cercariae were weighed alongside the samples to validate the method. We then generated
8
a cercaria density (μg/μm3) based on the direct measurements of the mass and volume of
9
Ribeiroia ondatrae and Echinostoma trivolvis cercariae. The average cercaria tissue
10
density, which was very similar for both trematode species (see Results in main text), was
11
then applied to volume estimates for the other four trematode taxa. The volume estimates
12
were obtained from measurements of micrographs made using ImageJ software
13
(Abramoff, Magalhaes & Ram 2004). Volume estimates were determined by converting
14
the body and tail of each cercariae (n > 5 cercariae per trematode taxon) into geometric
15
shapes with existing volume equations (Thieltges et al. 2008, Kuris et al. 2008).
16
Metacercaria and mesocercaria mass measurements were obtained by isolating
17
trematodes from amphibian and snail hosts and weighing them on pre-dried/pre-weighed
18
nylon filters in a manner similar to the cercariae described above. Sample sizes were as
19
follows: seven replicates of 100 or 200 metacercariae for Echinostoma trivolvis; four
20
replicates of 60 to 100 mesocercariae for Alaria sp.; five replicates of 30 metacercariae
21
for the amphistome; three replicates of 50 or 70 metacercariae for Cephalogonimus
22
americanus; and 19 replicates of 30 to 100 metacercariae for Ribeiroia ondatrae. For the
23
sixth trematode having the smallest metacercariae (Halipegus occidualis), we achieved
24
an estimated mass in a manner similar to the cercariae. We generated a metacercaria
25
density from two of the taxa (Ribeiroia ondatrae and Echinostoma trivolvis) for which
26
we directly measured both mass and volume and applied this density to volume
27
measurements of H. occidualis metacercariae.
28
References
29
Abramoff, M. D., Magalhaes, P. J. & Ram, S. J. (2004) Image processing with ImageJ.
30
Biophotonics International, 11, 36-42.
31
Kuris, A. M., Hechinger, R. F., Shaw, J. C., Whitney, K. L., Aguirre-Macedo, L., Boch,
32
C. A., Dobson, A. P., Dunham, E. J., Fredensborg, B. L., Huspeni, T. C., Lorda,
33
J., Mababa, L., Mancini, F. T., Mora, A. B., Pickering, M., Talhouk, N. L.,
34
Torchin, M. E. & Lafferty, K. D. (2008) Ecosystem energetic implications of
35
parasite and free-living biomass in three estuaries. Nature, 454, 515-518.
36
Thieltges, D. W., Montaudouin, X., Fredensborg, B., Thomas Jensen, K., Koprivnikar, J.
37
& Poulin, R. (2008) Production of marine trematode cercariae: a potentially
38
overlooked path of energy flow in benthic systems. Marine Ecology Progress
39
Series, 372, 147-155.
40
41
42
43
44
45
46
47
Table S1. Aquatic free-living organisms detected at three California ponds. The first
48
three columns provide the group or common name, the level of identification, and the
49
scientific classification for each taxon. The fourth column indicates whether or not we
50
included that taxon in our biomass estimates and the fifth column indicates whether or
51
not they were necropsied to quantify trematodes (only taxa that were known from the
52
literature to be a host in the life cycle of the detected trematode species were necropsied).
53
The group names in bold correspond to the taxa which appear in Figure 2 in the main
54
text.
Group and Common
Name
Oligochaeta
Oligochaete Worm
Oligochaete Worm
Oligochaete Worm
Hirudinea
Freshwater Leech
Copepoda
Copepod
Copepod
Cladocera
Cladoceran
Amphipoda
Amphipod
Ostracoda
California Clam Shrimp
Gastropoda
Ramshorn Snail
Emphemeroptera
Mayfly
Coleoptera
Crawling Water Beetle
Water Scaveneger Beetle
Water Scaveneger Beetle
Hemiptera
Backswimmer
Water Strider
Level of
Identification
Classification
Biomass Dissection
Genus
Family
Species
Dero
Tubificidae
Chaetogaster limnaei
No
No
No
No
No
No
Genus
Erpobdella
No
No
Genus
Family
Macrocyclops
Diaptomidae
No
No
No
No
Genus
Simocephalus
No
No
Genus
Hyalella
Yes
No
Species
Cyzicus californicus
Yes
Yes
Species
Helisoma trivolvis
Yes
Yes
Genus
Callibaetis
Yes
No
Genus
Genus
Genus
Haliplus
Hydrophilus
Tropisternus
Yes
Yes
Yes
No
No
No
Genus
Family
Notonecta
Gerridae
Yes
Yes
No
No
Water Boatmen
Giant Water Bug
Giant Water Bug
Diptera
Midge
Biting Midge
Shore Fly
Odonata
Eurasian Bluet Damselfly
Spreadwing Damselfly
Saddlebag Dragonfly
Green Darner Dragonfly
Amphibia
California Newt
Western Toad
Pacific Treefrog
California Red-legged Frog
55
56
57
58
59
60
61
62
63
64
65
66
67
68
Genus
Species
Genus
Hesperocorixa
Yes
Lethocerus americanus Yes
Belostoma
Yes
No
No
No
Family
Family
Family
Chironomidae
Ceratopogonidae
Ephydridae
No
No
No
No
No
No
Genus
Genus
Genus
Species
Coenagrion
Lestes
Tramea
Anax junius
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Species
Species
Species
Species
Taricha torosa
Anaxyrus boreas
Pseudacris regilla
Rana draytonii
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
69
Table S2. Length-to-dry mass regression equations for snails and three amphibian taxa.
70
Regressions for all other taxa where obtained from the literature. The table includes the
71
taxon name, the sample size for the regression, the size range of individuals used (mm),
72
the regression equation, and the r2 value of the regression. In the regression equations,
73
DM = dry mass in grams, and L = length in mm (snout-vent length for amphibian larvae
74
and shell length for snails).
Taxon
Snail Host
Helisoma trivolvis
Amphibian Hosts
Pseudacris regilla
Anaxyrus boreas
Taricha torosa
75
76
77
78
79
80
81
82
83
84
85
86
87
Sample
Size
Size Range
(mm)
Regression
Equation
r2
110
2.1 - 23.8
DM = (10-4)L2.17
0.77
25
25
47
3.3 - 12.1
5.2 - 17.0
9.6 - 23.5
DM = (2 x 10-6)L3.32
DM = (4 x 10-6)L3.34
DM = (2 x 10-7)L4.13
0.92
0.96
0.95
88
Table S3. Proportional trematode biomass within infected Helisoma trivolvis snails for
89
six trematode taxa that were detected at the three study ponds. The sample size indicates
90
the number of infected snail hosts that were dissected to quantify trematode and host dry
91
tissue mass. The percentage trematode tissue indicates the proportion of the total
92
host/parasite biomass that consisted of larval trematode tissue.
Trematode Taxon
Alaria sp.
Amphistome
Cephalogonimus americanus
Echinostoma trivolvis
Halipegus occidualis
Ribeiroia ondatrae
93
94
95
96
97
98
99
100
101
102
103
104
105
106
Sample
Size
8
9
5
8
7
9
% Trematode
Tissue
33.2
18.9
30.4
17.7
30.6
20.1
Standard
Error
3.2
1.8
2.5
1.6
2.4
1.0
107
Table S4. Infection prevalence (percent of the hosts infected out of the total number
108
dissected) of five trematodes in second intermediate hosts from three California ponds
109
(Quick, Sheep and North). We dissected at least 20 invertebrates and 30 amphibians per
110
species per pond. The sixth trematode taxon detected (amphistome) was only found in
111
snail first intermediate hosts and is not shown in the table. Dashes indicate that the
112
trematode does not infect that host as part of its life cycle, while zeros indicate the
113
trematode can infect that host, but was not detected. The suborders anisoptera and
114
zygoptera both include two respective taxa that were grouped for infection prevalence
115
estimates (anisoptera: Anax junius and Tramea; zygoptera: Lestes and Coenagrion; see
116
Table S1 for a full list of free-living taxa).
Quick Pond
Amphibians
Pseudacris regilla
Anaxyrus boreas
Taricha torosa
Invertebrates
Anisoptera
Zygoptera
Cyzicus californicus
Sheep Pond
Amphibians
Pseudacris regilla
Anaxyrus boreas
Taricha torosa
Invertebrates
Anisoptera
Zygoptera
Cyzicus californicus
North Pond
Amphibians
Pseudacris regilla
Taricha torosa
Invertebrates
R. ondatrae
E. trivolvis
C. americanus
Alaria sp.
H. occidualis
100
94.7
100
100
89.4
20.0
100
78.9
-
100
31.5
-
-
-
-
-
-
35.0
73.5
3.3
100
100
100
67.7
77.4
58.1
77.4
51.6
-
70.1
12.9
-
-
-
-
-
-
3.4
21.7
0
96.5
96.8
100
20.1
32.1
-
0
-
-
Anisoptera
Zygoptera
Cyzicus californicus
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
-
-
-
-
6.3
9.3
0