Dr. Jack Dumbacher is a Smithsonian Research Associate at the Conservation and Research Center and Molecular Genetics Lab. His research focuses primarily on the ecology and evolution of chemical defense in birds and the evolution of suites of characters that are often related withchemical defense, such as bright coloration and morphological variation.
In his Ph.D. work, he has used both field and laboratory techniques to study the avian genus Pitohui, which includes five toxic New Guinean bird species. Pitohuis carry a potent neurotoxic alkaloid in their skins and feathers, presumably for defense.
Pitohuis provide an interesting model system for the study of chemical defense and geographical variation, both because they are a rare avian model of chemicaldefense, and because they exhibit striking intraspecific phenotypic variation that contradicts some aspects of our understanding of the evolution of aposematism and mimicry.
Dr. Dumbacher’s research on pitohuis has involved the chemical isolation, characterization, and quantification of defensive chemicals, and studies of species targeted by defense (parasites and predators).
At the National Zoological Park, Dr. Dumbacher is currently
working on a molecular phylogeny for the genus Pitohui
and other genera in the avian family Pachycephalidae.
This work hopes to understand pitohui chemical defense in a phylogenetic and biogeographical context. Because of his interest in avian systematics and New Guinean phylogeography, Dumbacher has also recently been working on a collaborative project to unravel relationships within the Owlet-nightjars (genus Aegotheles) and among Aegotheles and other Caprimulgid families.
Dumbacher is currently working on two new projects. The first project is being done in collaboration with Scott Derrickson (National Zoo's Conservation and Research Center), John Daly and Thomas Spande (Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health), and Frank Bonaccorso (Papua New Guinea National Museum and Art Gallery.)
Together, they are organizing a field and laboratory study of the physiology and ecology of Hooded Pitohuis in New Guinea. They hope to radiotrack wild pitohuis, study their diet, mating habits, and home range needs. They hope to bring ten Hooded Pitohuis to the National Zoo, where they will study whether the pitohuis can produce toxins de novo or if they primarily sequester toxins from their diet.
In collaboration with Andy Mack (Conservation International),
Frank Bonaccorso (Papua New Guinea National
Museum and Art Gallery) and Rob Fleischer (Molecular
Genetics Lab, National Zoo), Dumbacher hopes to study
the avian phylogeography of Papua New Guinea using molecular
techniques. They hope to use molecular data to gather
evidence for and to roughly date the geological events
that were most important in shaping the current distribution
of birds species throughout the Papua New Guinea lowlands.
The information that they gain will be important to
understanding species diversity and distributions, and
be useful for conservation decisions makers.