Biology Reference
In-Depth Information
Fig. 4.12
Phylogeny of
poison frogs
(Dendrobatidae)
based on
molecular genetic
analysis. The ant
icons indicate two
origins of a
specialized diet,
and a possible
third origin is
indicated by a
question mark.
The column of
photos on the left
shows
representative
cryptic and
non-toxic species.
The column on
the right shows
conspicuous and
toxic species (the
toxicity of
A.
zaparo
is
unknown). Figure
from Santos
et al
.
(2003); by
courtesy of David
Cannatella and
Juan Carlos
Santos.
A
C. talamancae
A. femoralis
?
A. zaparo
B
C. sauli
C. infraguttalus
C
C. machalilla
E. tricolor
C. fugax
E. parvulus
D
P. bicolor
D. leucomelas
D. reticulatus
0.05 substitutions/site
from a generalist, cryptic ancestor within the Dendrobatidae family tree (Fig. 4.12;
Santos
et al
., 2003).
Why bright colours? In a letter to Charles Darwin, Alfred Russel Wallace suggested
an answer: 'Some outward sign of distastefulness is necessary to indicate to its
would-be destroyer that the prey is a disgusting morsel'. Wallace's hypothesis is that
bright colours are best as warning signals. Such warning colouration is known as
aposematism.
Wallace's
hypothesis:
warning signals
to reduce
predation
