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Fig. 2. Food intake (A) and metabolizable energy intake (B) as a function of body
mass for 12 male field voles prior to exposure to long day photoperiod (LD, 16
h:8 h L:D), during the increase phase (days 128 of LD exposure) and
during the plateau phase (days 2956 of LD exposure). Prior to exposure
to LD, the animals were kept in short day photoperiod (SD, 8 h:16 h L:D). The
measurements of food intake were repeated three times during the pre-exposure
phase and four times during the increase and plateau phases. After adjusting
for differences in body mass, photoperiod had no effect on food intake, but it
did have a significant effect on MEI (for statistical details, see Results).
The relationships are described by y=27.7+2.0x for
pre-exposure, y=26.0+2.4x for LD increase and
y=30.4+2.2x for LD plateau.