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Vol. 54, 2015
The function of body
coloration of the hai coral snake Sinomicrurus
japonicus boettgeri
Koji
Mochida1*, Wan-Yu Zhang2 and Mamoru Toda1
1Tropical
Biosphere Research Center, University of Ryukyus, Nishihara, Okinawa
903-0213, Japan
2Graduate School of Engineering and Science,
University of Ryukyus, Nishihara, Okinawa 903-0213, Japan
Abstract
Background: Prey animals often protect
themselves from visual hunting predators via their body coloration,
which encompasses various visual effects. When a prey animal displays a
certain color pattern on its body surface, its protective function and
effect are largely dependent on how a predator would encounter and
perceive the prey animal. Asian coral snakes of the genus Sinomicrurus, which are venomous,
display black bands and stripes on their orange body coloration. The
banded pattern has been characterized as an aposematic signal in the
New World coral snakes, but the stripes generally occur in cryptic
snakes. We investigated the function of this complex color pattern,
which might be interpreted as aposematic and cryptic, in Sinomicrurus japonicus boettgeri.
Results: First, plasticine replica experiments
were conducted to assess whether natural avian predators avoid the
color pattern of S. japonicus
boettgeri; the results showed that they attacked the coral snake
replicas and the control replicas with coloration similar to another
prey snake, suggesting that the body coloration of S. japonicus boettgeri did not function
aposematically in the wild. Second, we evaluated the chromatic contrast
of the snake coloration with backgrounds from their natural habitats
based on the avian predator visual systems. The body coloration of S. japonicus boettgeri showed the
same, or lower, contrast levels with natural backgrounds than those of
sympatric cryptic snakes, suggesting that the coloration was
ineffective as an aposematic signal.
Conclusions: These results imply
that the body coloration of S.
japonicus boettgeri would work as crypsis through background
matching or disruptive camouflage rather than aposematism.
Key words: Aposematism; Disruptive coloration;
Background matching; Coral snake mimicry.
*Correspondence: E-mail: kj.mochida@gmail.com
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