I'm interested in how natural selection shapes cognition, communication, and cooperation. I'm also fueled by an obsession with bats.
2010 - now: Evolution of helping behaviour in vampire bats
The evolution of cooperation is the centerpiece of an important debate in biology. Biologists generally agree that contingent investment and partner choice are important mechanisms responsible for stabilizing inter-specific mutualisms, but disagree on the degree to which similar mechanisms operate within vertebrate societies, where kin selection is already known to be important. Experiments on inter-specific mutualisms identify behavioral enforcement mechanisms by first replicating natural forms of cooperation in the lab, then testing responses to simulated cheating. Unfortunately, such rigorous and controlled experiments are often impossible for highly cognitive social species, such as primates. This is unfortunate because the necessity to enforce cooperation and prevent cheating has been proposed to be a key evolutionary force for advanced social cognition.
Food sharing among common vampire bats (Desmodus rotundus) provides a unique opportunity to test experimentally the behavioral, cognitive, and hormonal mechanisms used by a highly social mammal to enforce a costly and natural form of cooperation. In contrast to most other mammalian systems, it is possible to induce regurgitated food sharing, measure the cooperative investments and returns, and observe responses to ‘cheating’ in these long-lived socially complex animals. A network of both related and unrelated bats will accept and reject potential food sharing partners - conditions for testing key predictions derived from both inclusive fitness and biological market theories. I aim to identify the decision rules that determine when vampire bat donors regurgitate food to related and unrelated roostmates, and then to determine if those decisions are influenced by the neuropeptide oxytocin. I'm working in collaboration with the Organization for Bat Conservation.
2009: Learning and cognition in fruit and flower bats
During the spring and summer 2009, I worked as a research assistant at McMaster University on a project at the Montreal Biodome with support from John Ratcliffe and Jeff Galef. I investigated whether there was a possible evolutionary connection between dimethyl disulfide (found in bat flowers) and carbon disulfide (found in bat breath). I found no evidence for this however.
I next tested to see whether I could predict what types of cues (spatial, olfatory, and/or echo-acoustic) bats would use to remember food locations. Contrary to what I expected, I found that both the flower bat Glossophaga soricina and the fruit bat Carollia perspicallata use spatial memory over associated shapes and smells for re-locating food. I was funded by a NSERC grant to Jeff Galef.
2006 - 2008: Vocal communication in vampire bats
Bats are perhaps the most vocal animals on the planet. They produce the most intense biological airborne sounds (fortunately outside our hearing range), almost constantly while in flight. Unlike most animals, bats use sound both for perceiving the world and for signaling to others. Yet we know surprisingly little about how and why bats signal to others. My M.Sc. thesis at the University of Western Ontario investigated what kinds of sounds white-winged vampire bats (Diaemus youngi) produce, and how they perceive them. White-winged vampires possess a diverse repertoire of social calls in both the audible and ultrasonic range, and unlike some other bats, they will respond to playback. My preliminary work revealed at least five discrete categories of vocalizations used by adults in different contexts. I showed that double-note calls are emitted in precisely timed exchanges ("antiphonal" calling) and allow bats to tell each other apart from a distance. I did this by analyzing call structure variation among individuals and using playback experiments to demonstrate individual discrimination. As you would expect with "contact calls", I also found that both calling and call responding are more common when conspecifics are moving all over the place. To show this, I compared "real swaps" where I moved 4 caged bats in total darkness to "sham swaps" where I moved them the same amount, but then back to the same location. The bats replied to each other more often during real swaps then sham swaps. In other words, contact calling for these bats is like a game of "Marco-Polo". I worked in collaboration with Mark Skowronski , Brock Fenton and Paul Faure. I conducted my research with facilities and animals owned by Talking Talons and Daniel Abram.
Recently, in collaboration with the lab of Rodrigo Medellin, we've found that another rare vampire species also makes similar social calls, albeit not in an antiphonal pattern. I was funded by an Ontario Graduate Scholarship. (In 2008, I also worked as an after-school teacher in Vermont and hiked the 2,600 mile Pacific Crest Trail with my partner Michelle.)
2002 - 2005: Non-invasive molecular methods and terrestrial locomotion in bats
Everyone knows the vampire bat drinks blood. Biologists even know what domestic prey they prefer in agricultural areas. Yet for decades, researchers have only speculated about which wild animals they prey upon in their original habitats. While at Cornell University, I worked on developing the first non-lethal, non-invasive method of identifying the wild prey of vampire bats. Under the guidance of Irby Lovette at the Cornell Laboratory of Ornithology, I successfully extracted, amplified, and sequenced avian DNA from the feces of both captive and wild white-winged vampires (Diaemus youngi). This method is now being used by biologists in Latin America.
I also worked as an assistant to Dan Riskin and John Hermanson on terrestrial locomotion in bats. Specifically, we looked at the kinetics and kinematics of walking and running in vampires. My undergraduate research was graciously funded by the Cornell Presidential Research Scholars program.
Other interests