Chemical communication in juncos


In collaboration with Helena Soini and Milos Novotny of IU's Institute for Pheromone Research, I am examining variation in volatile compounds in junco preen oil using gas chromatography-mass spectrometry. The volatile compounds in junco preen oil increase dramatically when the birds are in breeding condition, suggesting that these compounds may be important in the context of reproduction (Soini et al 2007, J. Chem. Ecol.). Upon further investigation, we have found repeatable individual differences, consistent sex differences, and variation among different junco populations. I am investigating what other information may be contained in these chemosignals, such as genetic relatedness, MHC genotype (see below), or condition. We have also conducted a preliminary behavioral study with captive juncos that suggested they can discriminate among individuals on the basis of olfactory cues.

Publications
Whittaker, D. J., H. A. Soini, J. W. Atwell, C. Hollars, M. V. Novotny, and E. D. Ketterson. In press. Songbird chemosignals: Volatile compounds in preen gland secretions vary among individuals, sexes, and populations. Behavioral Ecology.

Presentations
Whittaker, D. J., H. A. Soini, J. W. Atwell, M. V. Novotny, and E. D. Ketterson. 2009. Evidence for chemosignaling in songbirds. (Talk presented at the American Ornithologists' Union annual meeting, Philadelphia, PA, August 2009)

Variation in passerine preen oil volatiles

Collecting preen oil from a grackle
Our preliminary data shows that different species have different volatile components in their preen oil. Our data from a field experiment  suggest that birds can recognize conspecific and heterospecific preen oil odors. In the summer of 2009, I sampled preen oil from a wide taxonomic range of passerine and non-passerine birds in Bloomington, IN in order to examine the relationship between volatiles, phylogeny, and environment.

Publications
Whittaker, D. J., D. G. Reichard, and E. D. Ketterson. 2009. Behavioral responses of nesting females to hetero- and conspecific passerine odors. Journal of Avian Biology 40: 579-583. (PDF)

Presentations
Whittaker, D. J., D. Reichard, and E. Ketterson. 2008. Birds smell: behavioral responses of nesting females to avian scents. (Talk presented at Indiana Academy of Science annual meeting, Evansville, IN, October 2008)

The Junco Transcriptome

Female junco


In collaboration with IU's Center for Genomics and Bioinformatics, we are sequencing the transcriptome of the dark-eyed junco. This new dataset will enable a plethora of new projects on junco and songbird evolution.



MHC-based mate choice in juncos


The major histocompatibility complex (MHC), a gene family involved in immune function, has been shown to play a role in mate choice in several species, though studies to date have given varying results. MHC genotype may be detected via odor, in sweat and urine and mammals and potentially in preen oil in birds. Three mate choice hypotheses have been suggested: 1) inbreeding avoidance, as individuals with different MHC types will be non-relatives, 2) compatible genotypes, as disassortative mating will produce heterozygous and therefore fitter offspring, or 3) “good genes,” as condition-dependent traits may rely on underlying MHC genotype. I am testing the following hypotheses in a well-studied songbird, the Dark-Eyed Junco: 1) female juncos evaluate potential mates using olfactory cues;  2) these olfactory cues communicate information about MHC genotype; and  3) population genetic patterns such as inbreeding influence MHC-based mate choice.  Furthermore, we are examining potential morphological (such as plumage) and physiological (such as steroid hormone levels) correlates of MHC genotype to test whether good genes advertisement is occurring. This research is supported by grants from the Indiana Academy of Science, the American Philosophical Society, and Indiana University.

Publications
Whittaker, D. J., J. W. Atwell, G. Cardoso, T. Price, and E. D. Ketterson. In revision. Diversity and selection at MHC loci in two ecologically distinct populations of Dark-eyed Juncos.

Presentations
Whittaker, D. J., J. W. Atwell, G. Cardoso, T. Price, and E. D. Ketterson. 2008. Flexibility in mate choice for MHC: a comparison of two ecologically distinct populations of Dark-eyed Juncos. (Poster presented at ISBE Congress, Ithaca, NY, August 2008)
Whittaker, D. J., J. W. Atwell, G. Cardoso, T. Price, and E. D. Ketterson. 2007. MHC-based mate choice and inbreeding avoidance in the Dark-Eyed Junco (Junco hyemalis). (Talk presented at Indiana Academy of Science annual meeting, Indianapolis, IN, October 2007)
Whittaker, D. J., J. W. Atwell, G. Cardoso, T. Price, and E. D. Ketterson. 2007. Do Dark-Eyed Juncos (Junco hyemalis) choose mates on the basis of MHC genotype? (Talk presented at the Animal Behavior Society meetings, Burlington, VT, July 2007)

Doctoral Research


Evolutionary Genetics of Kloss's Gibbons (Hylobates klossii): Systematics, Phylogeography, and Conservation


For this project, I investigated the genetic diversity of the Kloss's gibbon, endemic to the Mentawai Islands of Indonesia. These gibbons are a poorly studied species, and little is understood about their phylogenetic position within the gibbon radiation and patterns of genetic diversity within the species. The other endemic Mentawai primates (Macaca pagensis, Presbytis potenziani, and Simias concolor) have been suggested to be divided into two subspecies based on variation in coat color: one on Siberut in the northern end of the chain, and one subspecies on the three southern islands. The Kloss's gibbon shows no obvious variation, as all individuals are completely black. Furthermore, the primates of the Mentawai Islands are threatened by logging and hunting, and the conservation status of the Kloss's gibbon has not been evaluated since 1980. Based on mitochondrial D-loop sequences and their congruence with morphological and vocal characteristics as well as ND3-4 data, the Kloss's gibbon appears to be a recently derived member of the lar group of gibbons, clustering with the geographically close H. agilis and H. moloch, rather than a basal taxon as previous morphological studies have suggested. Based on the mitochondrial data, the Kloss's gibbon shows no genetic differentiation between islands. There are 20,000-25,000 Kloss's gibbons remaining in the wild, with the largest proportion located on Siberut. I evaluated the conservation status for all four Mentawai primate species and published a conservation action plan. I assessed the conservation status of these species at the 2006 Asian Primate Red List workshop and their status has been updated in the 2008 IUCN Red List. This research was funded by: a Doctoral Dissertation Improvement Grant from the National Science Foundation; The Charles A. and Anne Morrow Lindbergh Foundation; Primate Conservation, Inc.; and the New York Consortium in Evolutionary Primatology.

Publications:
Whittaker, D. J. 2009. Phylogeography of Kloss's gibbon (Hylobates klossii) populations and implications for conservation planning in the Mentawai Islands. In The Gibbons: New Perspectives on Small Ape Socioecology and Population Biology, ed. S. Lappan and D. J. Whittaker. New York: Springer, pp. 73-89.
Whittaker, D. J., J. C. Morales, and D. J. Melnick. 2007. Resolution of the Hylobates phylogeny: congruence of mitochondrial D-loop sequences with molecular, behavioral, and morphological datasets. Molecular Phylogenetics and Evolution 45: 620-628. (PDF)
Whittaker, D. J. 2006. Conservation action plan for the Mentawai primates. Primate Conservation 20: 95-106. (PDF)
Whittaker, D. J. 2005. New population estimates for the Kloss’s gibbon (Hylobates klossii). Oryx 39: 458-461. (PDF)
(Download the full 3.0 MB dissertation pdf.)


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