Pitohui |
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Scientific classification |
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Species |
See text. |
Pitohui is a genus of birds
endemic to New Guinea, belonging to the family
Pachycephalidae.
Currently six
species are classified in the genus, though current
molecular genetics research suggests that significant
reclassification of the Pachycephalidae may be needed.
Species
- Variable Pitohui, Pitohui kirhocephalus
Hooded Pitohui, Pitohui dichrous
White-bellied Pitohui, Pitohui incertus
Rusty Pitohui, Pitohui ferrugineus
Crested Pitohui, Pitohui cristatus
Black Pitohui, Pitohui nigrescens
Pitohuis are brightly coloured, omnivorous birds. The
skin and feathers of some pitohuis, especially the Variable
and Hooded Pitohuis, contain powerful neurotoxic alkaloids
of the batrachotoxin group (also secreted by the Colombian
poison dart frogs, genus Phyllobates). It is believed that
these serve the birds as a chemical defence, either against
ectoparasites or against visually guided predators such as
snakes, raptors or humans. (Dumbacher, et al., 1992) The
birds probably do not produce batrachotoxin themselves. It
is most likely that the toxins come from the Choresine genus of beetles, part of the bird's diet.[1]
(Dumbacher, et al., 2004)
The Hooded Pitohui is brightly coloured, with a brick red
belly and a jet black head. The Variable Pitohui, as its
name implies, exists in many different forms, and twenty
subspecies with different plumage patterns have been named.
Two of them, however, closely resemble the Hooded Pitohui.
It has been suggested that the birds' bright colours are
an example of aposematism (warning colouration), and the
similarity of the Hooded Pitohui and some forms of the
Variable Pitohui might then be an example of Müllerian
mimicry, in which dangerous species gain a
mutual advantage by sharing colouration, so that an
encounter with either species trains a predator to avoid
both. (Dumbacher & Fleischer, 2001)
References
- Dumbacher JP,
Beehler BM, Spande TF, Garraffo HM, Daly JW (1992). "Homobatrachotoxin
in the genus Pitohui: chemical defense in birds?".
Science 258 (5083): 799-801.
PMID 1439786.
- Dumbacher JP,
Fleischer RC (2001). "Phylogenetic evidence for colour
pattern convergence in toxic pitohuis: Mullerian mimicry
in birds?".
Proceedings of the Royal Society of London B
268 (1480): 1971-6.
PMID 11571042.
- Dumbacher JP, Wako
A, Derrickson SR, Samuelson A, Spande TF, Daly JW
(2004). "Melyrid beetles (Choresine): a putative source
for the batrachotoxin alkaloids found in poison-dart
frogs and toxic passerine birds".
Proceedings of the National Academy of Sciences
101 (45): 15857-60.
PMID 15520388.
External links