Transcription of Data. Videos of waggle dances were transcribed using QuickTime (v7, http://www.apple.com/quicktime). We measured the directional precision of the dance as the SD of dance angles and the distance precision as the CV of waggle phase durations. The CV was calculated to compare the precision of waggle phase durations, because this measure takes into account magnitudes of means. The CV could not be applied to the comparison of directional precision, because mean angles were often close to 0 or negative, making comparisons less meaningful. The time and place of each waggle phase start and end point were transcribed by playing the videos frame-by-frame beneath a transparent Web browser (aeroFox v1.0.5), and using the computer mouse to click on a single point of a dancing bee viewed through the transparent browser window (Fig. S2). Of the dancer's body regions, the head moves the least in the lateral direction (13); thus, a point located medially and immediately posterior to the head was selected to establish the start and end points of a waggle phase. A.K. wrote a computer program that calls the JavaScript libraries jQuery (1.2.1) (http://jquery.com/) and Walter Zorn's Vector Graphics Library (3.0.3) to store each pair of browser-based mouse-click coordinates in a MySQL database, and wrote a second program in Python (v2.6, http://www.python.org) to compute dance angles and waggle phase durations from the pairs of mouse clicks (SI Appendix). Data transcription was done blindly, and interobserver error for calculating angles was 1.06% ± 0.24% (3.33 ± 0.82 degrees).