Data Supplements

Files in this Data Supplement:

• Supplemental Figure 1 - Measurements of field intensity. Field intensity was measured at various distances from the water-bridge electrodes in order to estimate current density. The position of the two measuring electrodes is indicated by two small squares connected by a line. Measurements are shown for electric fields generated by electrodes separated by (A) 1 cm and (B) 5 cm (as shown in Fig. 1B). Units of measured field strength are mV/cm.
• Supplemental Figure 2 - Cumulative duration of active behaviors per animal at the electrodes in electric fields generated by electrodes 1 cm apart. Data are standardized by subtracting the value for each animal in a control test (no electric field) from that in an electric field test. Asterisks indicate that values in the electric field are significantly different from values in the control (Wilcoxon matched pairs test, P<0.05). Values are means ± S.E.M. Data are summarized in Table 1.
• Supplemental Figure 3 - Number of touches per animal in electric fields generated by electrodes 1 cm apart. Data are standardized by subtracting the value for each animal in a control test (no electric field) from that in an electric field test. Asterisks indicate that values in the electric field are significantly different from values in the control (Wilcoxon matched pairs test, P<0.05). Values are means ± S.E.M. Data are summarized in Table 1.
• Supplemental Figure 4 - Number of active behaviors per animal involving claws down on the gravel close to the electrodes in electric fields generated by electrodes 1 cm apart. Data are standardized by subtracting the value for each animal in a control test (no electric field) from that in an electric field test. Asterisks indicate that values in the electric field are significantly different from values in the control (Wilcoxon matched pairs test, P<0.05). Values are means ± S.E.M. Data are summarized in Table 1.
• Supplemental Figure 5 - Number of tugs and grabs of the electrodes per animal in electric fields generated by electrodes 1 cm apart. Data are standardized by subtracting the value for each animal in a control test (no electric field) from that in an electric field test. Asterisks indicate that values in the electric field are significantly different from values in the control (Wilcoxon matched pairs test, P<0.05). Values are means ± S.E.M. Data are summarized in Table 1.
• Supplemental Figure 6 - Behavior of crayfish in electric field of ~ 1 mV/cm intensity and 4 Hz frequency when electrodes were 5 cm apart (Fig. 1B). The total current flowing between the electrodes in this configuration (2.59 µA) is approximately the same as that for electrodes 1 cm apart and a field intensity of 20 mV/cm. Behaviors shown in this figure are: (A) Cumulative duration of active behaviors; (B) Number of touches of the electrodes; (C) Number of active behaviors involving claws down on the gravel close to the electrodes; and (D) Number of tugs and grabs of the electrodes per animal. Data are standardized by subtracting the value for each animal in a control test (no electric field) from that in an electric field test. Asterisk indicates values in the field that are significantly different from values in the control (Wilcoxon matched pairs test, P<0.05). Values are means ± S.E.M.