About the Authors
Department of Biology, York University, Toronto, Ontario, Canada
The authors have declared that no competing interests exist.
Conceived and designed the experiments: PAC BLN BW WX KAW. Performed the experiments: PAC BLN BW WX. Analyzed the data: PAC BLN BW WX KAW. Contributed reagents/materials/analysis tools: PAC BLN BW WX KAW. Wrote the paper: PAC KAW.