Summary of kinematic changes for each individual in response to loading.

<p>Arrows represent significant positive (↑) or negative (↓) changes of a variable in response to 20% increase in body mass. Significance at α = 0.05.</p

Vertical force coefficient for bats in control and loaded conditions.

<p>Relationship between the vertical force coefficient, <i>C</i>_v, and flight speed for control (open triangles) and loaded (grey circles) flights. Each point represents the mean value for a particular trial, using only wind tunnel flights.</p

Morphological measurements of the three individuals used in this study.

<p>Measurements were performed following Norberg and Rayner <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036665#pone.0036665-Norberg1" target="_blank">[11]</a>.</p

Wing motion parameters for bats in control and loaded conditions.

<p>Relationship between wingbeat frequency (A), wingbeat amplitude (B), and stroke plane angle (C) with flight speed. Open triangles represent control flights, grey circles represent loaded flights. Each point represents the mean value for a particular trial, using both wind tunnel and flight corridor flights.</p

Markers and segmentation used in this study.

<p>Ventral view diagram of a bat indicating (A) the position of the wing and body markers and (B) the triangular segmentation used to calculate surface area, vertical force coefficient (<i>C</i>_v), and angles of attack. The dotted lines indicate the 11 segments used to calculate surface area and <i>C</i>_v and the grey-shaded triangles represent the segmentation used to calculate the proximal (prox) and distal (dist) angles of attack. ank, ankle; d3, d4 and d5, distal end of of distal phalanx of digits III, IV and V, respectively; ip, interphalangeal joint of digit V; mcp, metacarpal-phalangeal joint of digit V; pvs, pelvis; shd, shoulder; str, sternum; wst, wrist. Black markers indicate the markers used in the flight corridor trials.</p

Body mass of experimental subjects for wind tunnel and flight tunnel corridor experiments, prior to the experiment, immediately after injection, and immediately after the end of the experiment.

<p>Body mass in g. Percentage of increase with respect to original mass appears in parenthesis.</p

Supplementary figures from Dynamic finite-element modelling of the macaque mandible during a complete mastication gape cycle

Figure S1: Electromyographic (EMG) data from masticatory muscles when the animal was chewing on nuts, dried fruit, and grapes, throughout a standardized gape cycle, from maximum gape to the next maximum gape. Lines indicate the mean root mean square (RMS) EMG x PCSA x 30 N/cm2, for both working and balancing sides (blue and orange lines, respectively). The dotted vertical line indicates the timing of maximum strain in the lower lateral gauge (46%) used for our past static FEMs [5, 6]. The dashed vertical line indicated the timing of peak bone strains and peak moments in the dynamic simulations (nuts, 40%; grapes, 37%; dried fruit, 39%). Note peak moments for grapes for the No-Screws Model is at 35% of the gape cycle.Figure S2: Moments (in N m; force [N] x distance [m]) acting about axes parallel to the coordinate system on the right (balancing) side, on the left (working) side, and through the symphyseal region of the macaque mandible at the Screws Model. Different line colours show moments acting on those sections at different times during the gape cycle; dark blue indicates moments at the time of peak moments. The precise % of the gape cycles for the three food types are: dry fruit, 5, 14, 22, 31, 39; nuts, 5, 14, 23, 31, 40; soft food, 5, 13, 21, 29, 37. Numbers on the ordinate correspond to section planes illustrated in the figures at bottom. Moments about X (SI) axes are transverse bending moments; moments about Y (AP) axes are twisting moments; moments about Z (ML) axes are sagittal bending moments. Balancing-side frontal and working-side frontal: these moments are calculated as the sums of all the moments acting on the bone anterior to frontal planes through the illustrated sections. This includes those moments acting on the contralateral hemimandible, whether behind or in front of the section plane. Symphysis frontal: moments about frontal planes through the symphyseal region summed anterior to the illustrated sections. Symphysis sagittal: moments about sagittal planes through the symphyseal region summed to the right of the illustrated sections.Abbreviations: SI=superoinferior; AP=anteroposterior; ML=mediolateral.Figure S3: Maps of distribution of minimum principal strains (ɛ3) in the No-Screws Model at ∼10-50% of the chewing cycle when the animal was chewing on A) Nuts, B) Grapes, C) Dried fruit. Warmer and cooler colors represent lower and higher ɛ3 concentrations, respectively.Figure S4: Maps of maximum principal strains (ɛ1) in the Screws model surface at 10-50% of the gape cycle when the animal was chewing on A) Nuts, B) Grapes, C) Dried fruit. Warmer and cooler colors represent higher and lower ɛ1 concentrations, respectively.Figure S5: Maps of distribution of minimum principal strains (ɛ3) in the Screws Model at ∼10-50% of the chewing cycle when the animal was chewing on A) Nuts, B) Grapes, C) Dried fruit. Warmer and cooler colors represent lower and higher ɛ3 concentrations, respectively.Figure S6. Differences in electromyographic (EMG) data from jaw-adductor muscles when the animal was chewing on nuts and grapes throughout a standardized gape cycle, from maximum gape to the next maximum gape. Positive values indicate that the EMG when chewing on nuts was higher than when chewing on grapes. Negative values show that the EMG when chewing on grapes was higher than when chewing on nuts. The dotted vertical line indicates the timing of maximum strain in the lower lateral gauge (at 46% of the gape cycle) used for our past static FEMs [5, 6]. The dashed vertical line indicates the timing of peak bone strains and peak moments (at ∼40% of the gape cycle) in the dynamic simulations.Figure S7: Axial strain regimes at ∼40% of the gape cycle in the No-Screws FEMs during simulated nut (40% of the gape cycle), dried fruit (39%), and grape chewing (37%). A–F) XY (sagittal) shear strains. G–L) XZ (coronal). M–R) YZ (transverse) planes. A–F) XX (superoinferior) axial strains. G–L) ZZ (medial-lateral) axial strains. M–R) YY (anteroposterior) axial strains. Scale is in microstrain, warm colours indicate positive strain (increase in relative length), cool colors indicate compressive strain (decrease in relative length). Converging blue and red arrows respectively highlight areas of compression and tension.Figure S8: Axial strain regimes at ∼40% of the gape cycle in the Screws FEMs during simulated nut (40% of the gape cycle), dried fruit (39%), and grape chewing (37%). A–F) XY (sagittal) shear strains. G–L) XZ (coronal). M–R) YZ (transverse) planes. A–F) XX (superoinferior) axial strains. G–L) ZZ (medial-lateral) axial strains. M–R) YY (anteroposterior) axial strains. Scale is in microstrain, warm colours indicate positive strain (increase in relative length), cool colors indicate compressive strain (decrease in relative length). Converging blue and red arrows respectively highlight areas of compression and tension.Figure S9: Shear strain regimes at ∼40% of the gape cycle in the Screws FEMs during simulated nut (40% of gape cycle), dried fruit (39%), and grape chewing (37%). A–F) XY (sagittal) shear strains. G–L) XZ (coronal). M–R) YZ (transverse) planes. Scale is in microstrain, warm colours indicate positive strain (increase in relative length), cool colours indicate compressive strain (decrease in relative length)

Movie S7: from Dynamic finite-element modelling of the macaque mandible during a complete mastication gape cycle

Comparison of principal strains magnitudes on the surface of the mandible during nut chewing. Bottom plot is the ratio between tension and compression, indicative of the most prevalent component. Middle right plot shows the 99th percentile of principal strains (tension and compression) with time, as a % of the gape cycle

Table S3: from Dynamic finite-element modelling of the macaque mandible during a complete mastication gape cycle

Muscle force data during a complete mastication gape cycle during grape chewing

Movie S1: from Dynamic finite-element modelling of the macaque mandible during a complete mastication gape cycle

Dynamic changes in maximum principal strain (ɛ1) when chewing on nuts. Undeformed model has exterior edges, deformed model is shaded. Deformation scale factor is 50. Frame rate (frames/second)=3