Diameter, shell length and breaking force
| Species . | Thread diameter (μm) . | Range in shell length (mm) . | Breaking force (N) . |
|---|---|---|---|
| Geukensia demissa (S) | 37.6±2.2 (32) | 62.2–76.9 [69.1±1.6] (11) | 0.074±0.008 (19)A |
| Modiolus modiolus (S) | 46.3±2.4 (28) | 49.2–72.3 [57.9±2.0] (12) | 0.218±0.009 (20)A |
| Mytilus californianus (E) | 149.6±6.6 (30) | 49.4–91.4 [70.0±6.1] (7) | 1.636±0.129 (21)B |
| Mytilus edulis (E) | 132.3±6.0 (55) | 58.6–88.4 [72.6±3.4] (10) | 1.018±0.074 (25)C |
| Perna canaliculus (E) | 129.7±8.2 (34) | 50.0–70.0 [62.3±2.7] (7) | – |
| Species . | Thread diameter (μm) . | Range in shell length (mm) . | Breaking force (N) . |
|---|---|---|---|
| Geukensia demissa (S) | 37.6±2.2 (32) | 62.2–76.9 [69.1±1.6] (11) | 0.074±0.008 (19)A |
| Modiolus modiolus (S) | 46.3±2.4 (28) | 49.2–72.3 [57.9±2.0] (12) | 0.218±0.009 (20)A |
| Mytilus californianus (E) | 149.6±6.6 (30) | 49.4–91.4 [70.0±6.1] (7) | 1.636±0.129 (21)B |
| Mytilus edulis (E) | 132.3±6.0 (55) | 58.6–88.4 [72.6±3.4] (10) | 1.018±0.074 (25)C |
| Perna canaliculus (E) | 129.7±8.2 (34) | 50.0–70.0 [62.3±2.7] (7) | – |
Values are means ± s.e.m., followed by the sample size (N). The threads of semi-infaunal species, marked `S', were significantly thinner than those of epifaunal species, marked `E' (ANOVA, Scheffe test: P<0.0001; Kruskal–Wallis: P<0.0001). Shell length ranges of sampled individuals were strongly overlapping. In the`Breaking force' column, values marked with the same superscript letter are not significantly different from one another (Scheffe test: P<0.0001). M. californianus threads broke at significantly higher forces than M. edulis threads