Biology Reference
In-Depth Information
from masquerade because predators mistake them for something inedible, whereas
predators may also gain from masquerade because unsuspecting prey approach within
striking range. Masquerade, therefore, involves camouflage without crypsis; the
organism may be detected but it is not recognized as a prey or predator.
How could we distinguish whether an organism has been detected but misidentified
(masquerade) rather than been undetected (crypsis)? John Skelhorn and colleagues
(2010) did this by manipulating predators' experience of the inedible object while
keeping their exposure to the masquerader constant. Their experiment involved
Masquerade
versus crypsis
(a)
(i)
(ii)
(b)
1.00
0.80
0.60
0.40
0.20
0
10
20
30
40
50
60
70
Time (hours)
Fig. 4.10
Countershading. (a) (i) This eyed hawkmoth caterpillar,
Smerinthus ocellata
,
feeds with its ventral surface uppermost. It has a darker ventral surface which, when lit
from above combines with the shadow on the dorsal surface (below) to give it a uniform
reflectance, which helps to conceal its body shape. (ii) When turned, so it is now
illuminated dorsally, the lighter dorsal surface is highlighted and the darker ventral
surface is now in shadow, creating a more pronounced gradient and rendering the
caterpillar more conspicuous. Photos © Hannah Rowland. (b) An experiment with pastry
'caterpillars' pinned to the upper surface of branches in a wood. The countershaded
caterpillars (dashed light blue line) survived better than plain dark (red line), plain light
(purple line) or reverse-shaded prey (darker ventral surface; dark blue line). From
Rowland
et al
. (2008).
