Figure 2.

Results of load-lifting tests in bees with experimentally manipulated wing stiffness. (a) A string with evenly spaced, uniform bead groups was attached to a bee's petiole, applying an asymptotically increasing load as the bee ascended. Three to six load-lifting trials per bee were captured on video, and maximum vertical aerodynamic force was calculated as where g is the earth's gravity, n the maximum number of bead groups lifted, and m_bead and m_bee are mass per bead group and bee body mass. (b) Maximum vertical aerodynamic force produced by 14 bees (B1–B14, arranged by increasing wing span) subject to both the control splint (red) and joint splint (blue) treatments and three bees (S1–S3) subject to sham treatments. Bees that received the joint splint treatment first are indicated with an asterisk. Bar height encompasses measurement uncertainty, owing to both the mass of an individual bead group (measurement resolution is limited by the discrete n × m_bead term) and any decrease in body mass between the beginning and end of a flight trial.