Fig 1.
(A) Arrangement of 9.5 L (30 X 15 X 15 cm) aquaria used for all behavioral assays throughout the five-month study period. The subject in its home tank was placed between a pair of aquaria each housing an adjustable motorized belt and pulley system. The male dummy stimulus was attached to the pulley system situated in the aquarium to the right side of the subject’s home tank for all behavioral assays. When the apparatus was turned on, the dummy fish began ‘pacing’ back and forth along the glass facing the subject tank. An iPad was used to record the subject’s behavior for 5 min following the removal of opaque barriers blocking his view of the dummy in the neighboring tank. (B) Image used to create the 6.3 cm total length male dummy used in all behavioral assays.
Fig 2.
Means (±SE) for behaviors directed toward the male dummy stimulus.
The amount of time (sec) males in the low-dose (LD; 40 μg/L metformin), high-dose (HD; 80 μg/L metformin), and the control groups (C; no metformin exposure) spent gill flaring in each of three sequences of identical behavioral assays (pre-exposure, 4 weeks exposure, and 20 weeks exposure). Letter designations (a and b) correspond with significant p-values presented in Table 1 and indicate significant differences among the low-dose, high-dose, and control group means within a given time period of testing (e.g. comparing the HD vs LD vs C group responses after four weeks exposure) (See Table 1 for statistical results).
Fig 3.
Means (±SE) for behaviors directed toward the male dummy stimulus.
The amount of time (sec) males in the LD, HD, and C groups spent fin spreading in each of the three sequences of behavioral assays (PE, 4-WK, and 20-WK). The letter designation (c) corresponds with significant p-values presented in Table 1 and indicate significant differences among the low-dose, high-dose, and control group means within the given time period of testing (See Table 1 for statistical results).
Fig 4.
Means (±SE) for behaviors directed toward the male dummy stimulus.
Number of tail beats subjects in the LD, HD, and C groups directed towards the male dummy in each of the three sequences of behavioral assays (PE, 4-WK, and 20-WK). The letter designation (d) corresponds with significant p-values presented in Table 1 and indicate significant differences among the low-dose, high-dose, and control group means within the given time period of testing (See Table 1 for statistical results).
Table 1.
Results of RMANOVAs comparing mean behavior scores among the three treatment groups (LD vs. HD vs. controls).
Table 2.
Results of RMANOVAs comparing mean behavior scores across three rounds of testing (PE vs. 4-WK vs. 20-WK).