View larger version (75K):
[in a new window]
|
Fig. 1. (A) Photographs showing varying levels of expression of spots and blotches.
Letters A-D identify four individual plaice out of the six used in the study.
The modifiable features can be seen by comparing the images at the four
corners of the figure. Spots are readily identified, the blotches are
confusable with fixed dark patches, three of which are clearly seen on fish A.
Images were scored blind (see Materials and methods). The three different
backgrounds are illustrated. Background 1 in the left column, background 2 at
the lower right and background 2 at the upper middle. It is apparent that the
fish can regulate the expression of spots and blotches continuously and
independently. On background 1, spots and blotches are expressed at a low
level. On background 2, spots are dominant, with the white spots giving an
impression of transparency, which is a very effective camouflage technique. On
background 3, both spots and blotches are clearly expressed. (B) Responses of
plaice to the three different backgrounds. Data are for six individuals each
recorded twice on the three backgrounds, after at least 15 min
acclimatisation. Plots show the levels of expression of spots and blotches in
each of the twelve images for each background. The greyscale indicates the
proportion of occasions on which a given combination of spots and blotches
were seen. Table 1. The
background has significant effect on coloration pattern (see
Table 1). (C) Changes in level
of expression of spots and blotches associated with the transition between
each of the three pairs of backgrounds. The values plotted are based on scores
of the sign but not the magnitude of the change in expression associated with
a transition between a pair of backgrounds. See main text for details. Changes
in levels of expression all differ significantly from zero
(P<0.05), with the exception of blotches in transition 1 2
(see Results).
|
