I am intrigued by the unseen external forces that influence our behavior, mate choice, and, ultimately, evolutionary trajectories. My research is focused on the interaction between the microbiome and animal behavior, and the resulting impact on evolutionary dynamics. Specifically, I study chemical communication in a songbird, the dark-eyed junco (Junco hyemalis), the uropygial gland microbiome’s role in the production and evolution of chemical signals present in preen oil, and the effects of social behavior on these symbiotic microbes.
For a complete list of publications, see the CV page.
Whittaker, D. J., N. M. Gerlach, S. P. Slowinski, K. P. Corcoran, A. D. Winters, H. A. Soini, M. V. Novotny, E. D. Ketterson, and K. R. Theis. 2016. Social environment has a primary influence on the microbial and odor profiles of a chemically signaling songbird. Frontiers in Ecology and Evolution 4:90.
We investigated the relative contributions of shared environments and genetic relatedness in shaping juncos’ symbiotic bacterial communities, and tested whether these communities underlie juncos’ chemical signaling behavior. To address these questions, we sampled parents and nestlings at 9 nests during one breeding season. Mated adult pairs showed high bacterial similarity, and offspring were more similar to their mothers than fathers. When comparing offspring to their social fathers, paternity did not influence bacterial profiles; full siblings were not more similar than half siblings. Our data suggest that social environment is a primary driver of individual microbiota and odor profile structure among juncos: birds who are in close proximity and in frequent contact develop similar profiles.
Whittaker, D. J. and K. R. Theis. 2016. Bacterial communities associated with junco preen glands: ramifications for chemical signaling. In Chemical Signals in Vertebrates 13, eds. Bruce A. Schulte, Thomas E. Goodwin, and Michael H. Ferkin. New York: Springer International Publishing, pp. 105-117. (peer-reviewed book chapter)
We conducted a preliminary bacterial survey of the preen gland microbiome in free-living juncos. We found that, much like mammalian scent glands, the preen gland harbors diverse communities of symbiotic odor-producing bacteria. Two of the most common genera in junco preen glands, Burkholderia and Pseudomonas, are capable of producing over half of the volatile compounds present in junco preen oil, making these bacteria a candidate mechanism for odor production in juncos.
Whittaker, D. J. and N. M. Gerlach. 2016. Mate choice in dark-eyed juncos using visual, acoustic, and chemical cues. In Snowbird: Integrative Biology and Evolutionary Diversity in the Junco, eds. E. D. Ketterson and J. W. Atwell. Chicago: University of Chicago Press, pp. 281-309. (peer-reviewed book chapter)
This book chapter appeared in a book that was one of the results of Ellen Ketterson’s NSF OPUS grant. We reviewed junco preferences for visual, acoustic, and chemical traits in the context of mate choice. A large section of the chapter is devoted to reviewing the relatively recent literature on avian chemical signaling, focusing especially on our work in juncos. We ended by discussing the limits of what we can learn from typical mate-choice studies.
Whittaker, D. J., D. G. Reichard, M. Drouilly, K. Battle, and C. Ziegenfus. 2015. Avian olfactory displays: A new hypothesis for the function of bill-wiping in a social context. Behavioral Ecology and Sociobiology 69: 159-167.
We suggest that bill-wiping in social contexts – previously dismissed as a “displacement activity” – may function as an olfactory display that releases odor from preen oil dried on the bill and increases attractiveness, similar to self-grooming in mammals. In a field study, we presented resident male juncos with either a male or female intruder paired with vocalization playbacks to simulate either a same-sex territorial intruder, or a potential mate. We found that bill-wiping appeared to be an integral part of courtship, especially in younger males, but not of aggressive behavior. We also tested whether friction increased the attractiveness of dried preen oil in a captive Y-maze study, but the results were inconclusive.
Whittaker, D. J., N. M. Gerlach, H. A. Soini, M. V. Novotny, and E. D. Ketterson. 2013. Bird odour predicts reproductive success. Animal Behaviour 86(4): 697-703.
We measured preen oil volatile compounds in free-living adult juncos at the beginning of the breeding season, and tested their relationship with individual genetic reproductive success in that season. We found strong sex-specific relationships between reproductive success and sexually dimorphic volatile compounds, such that females with a more “female-like” odor and males with a more “male-like” odor had more offspring. Male odor was also correlated with survival of offspring in their home nest, as well as the number of extra-pair offspring in their nest. We conclude that preen oil volatile compounds may serve as reliable mate assessment cues in songbirds.
- Science Magazine, June 29, 2016: “Bacteria give bird its sexy smells.”
- The Secret Life of Scientists and Engineers: Danielle Whittaker: Evolutionary Biologist/Roller Derby Referee
- Michigan State University press release, November 11, 2013: “Bacteria may allow animals to send quick, voluminous messages.”
- Live interview on Ray’s Brown’s Talkin’ Birds radio show, October 6, 2013: Show #443 “The scent of birds — And why it’s a big deal—really big.”
- Nature Research Highlights, September 19, 2013: “Fertility smells like preen spirit.” Nature 501: 285.
- Discover Magazine blog “D-brief,” September 6, 2013: “Birds can whiff a winner of a mate.”
- Audubon Magazine blog, September 4, 2013: “Better-smelling birds produce more offspring.”
- CBS News, September 4, 2013: “For birds, looks just ain’t enough.”
- Grist, September 4, 2013: “Birds like their boyfriends to smell good.”
- Futurity.org, September 4, 2013: “Smell can sweeten birds’ chances of mating.“
- NSF News from the Field, September 3, 2013: “Birds choose sweet-smelling mates.” (Featured on the front page of nsf.gov)
- Science Daily, September 3, 2013: “Birds choose sweet-smelling mates.”
- Michigan State University press release, September 3, 2013: “Birds choose sweet-smelling mates.”
- Science Magazine, ScienceShot, August 16, 2013: “Forget plumage, birds sniff out good mates.”
- The Berkeley Daily Planet, July 26, 2011: “Wild neighbors: smelling like a bird.”
- Futurity.org, July 22, 2011: “Songbird ‘cologne’ drives females wild.”
- Science Daily, July 19, 2011: “Avian ‘Axe effect’ attracts attention of females and males.”
- Michigan State University press release, July 19, 2011: “Avian ‘Axe effect’ attracts attention of females and males.”
- LiveScience, April 21, 2010: “Songbirds hold secrets of attracting mates.”
- Science Daily, March 24, 2010: “Could smell play a role in the origin of new bird species?” Indiana University press release, March 23, 2010: “Could smell play a role in the origin of new bird species?”