Fig. 5. Responses in (A,C) heart rate (fH) and (B,D) appendage
beating rate (fA) to decreasing ambient oxygen tensions at
food-free conditions (left; N=5) and food-rich conditions (right;
105 algal cells ml-1; N=11 except for 0.8 kPa,
where N=4). Data are given as means ± S.D. A
repeated-measures ANOVA was performed for all data. At food-free conditions,
the mean fA (F=25.6, groups d.f.=9, remainder
d.f.=36, P<0.001) and the mean fH
(F=48.0, groups d.f.=6, remainder d.f.=36, P<0.001) were
not the same in animals on all 10 oxygen levels. At food-rich conditions, the
mean fA (F=3.1, groups d.f.=9, remainder d.f.=36,
P=0.025) and the mean fH (F=15.4, groups
d.f.=9, remainder d.f.=36, P<0.001) were not the same in animals
on all 10 oxygen levels. The results of multiple comparisons among pairs of
means are shown in Tables 3,
4.