Comparison of friction, contact area and shear stress, as well as adhesion between proximal and distal slides in single pads of stick insects and beetles
| Smooth system Carausius morosus . | . | Proximal slide . | Distal slide . | Paired t-test, d.f.=6 . |
|---|---|---|---|---|
| Friction | ||||
| Little secretion | Force (mN) | 27.1±4.2 | 11.9±1.6 | t=3.30, P=0.016 |
| Contact area (μm2) | 102,411±19,885 | 57,839±18,847 | t=2.22, P=0.068 | |
| Shear stress (kPa) | 298.9±60.2 | 307.1±54.3 | t=0.13, P=0.898 | |
| Accumulated secretion | Force (mN) | 17.3±3.0 | 6.30±0.96 | t=3.17, P=0.019 |
| Contact area (μm2) | 96,651±20,445 | 36,684±6445 | t=2.54, P=0.044 | |
| Shear stress (kPa) | 205.8±31.0 | 189.1±27.5 | t=0.59, P=0.574 | |
| Adhesion | ||||
| Little secretion | Force (mN) | 4.25±0.96 | 0.47±0.17 | t=4.48, P=0.001 |
| Accumulated secretion | Force (mN) | 2.28±0.47 | 0.38±0.16 | t=4.41, P=0.001 |
| Hairy system Gastrophysa viridula | ||||
| Friction | ||||
| Little secretion | Force (mN) | 11.1±0.9 | 1.43±0.23 | t=11.17, P<0.001 |
| Contact area (μm2) | 22,448±2132 | 6117±650 | t=6.06, P=0.001 | |
| Shear stress (kPa) | 518.5±48.9 | 233.0±28.6 | t=3.72, P=0.010 | |
| Accumulated secretion | Force (mN) | 5.53±0.94 | 1.62±0.24 | t=3.91, P=0.008 |
| Contact area (μm2) | 20,626±1786 | 13,389±1105 | t=3.04, P=0.023 | |
| Shear stress (kPa) | 293.8±63.9 | 134.9±31.0 | t=2.03, P=0.089 | |
| Adhesion | ||||
| Little secretion | Force (mN) | 1.78±0.27 | 0.17±0.09 | t=5.71, P=0.001 |
| Accumulated secretion | Force (mN) | 1.05±0.08 | 0.21±0.09 | t=6.85, P<0.001 |
| Smooth system Carausius morosus . | . | Proximal slide . | Distal slide . | Paired t-test, d.f.=6 . |
|---|---|---|---|---|
| Friction | ||||
| Little secretion | Force (mN) | 27.1±4.2 | 11.9±1.6 | t=3.30, P=0.016 |
| Contact area (μm2) | 102,411±19,885 | 57,839±18,847 | t=2.22, P=0.068 | |
| Shear stress (kPa) | 298.9±60.2 | 307.1±54.3 | t=0.13, P=0.898 | |
| Accumulated secretion | Force (mN) | 17.3±3.0 | 6.30±0.96 | t=3.17, P=0.019 |
| Contact area (μm2) | 96,651±20,445 | 36,684±6445 | t=2.54, P=0.044 | |
| Shear stress (kPa) | 205.8±31.0 | 189.1±27.5 | t=0.59, P=0.574 | |
| Adhesion | ||||
| Little secretion | Force (mN) | 4.25±0.96 | 0.47±0.17 | t=4.48, P=0.001 |
| Accumulated secretion | Force (mN) | 2.28±0.47 | 0.38±0.16 | t=4.41, P=0.001 |
| Hairy system Gastrophysa viridula | ||||
| Friction | ||||
| Little secretion | Force (mN) | 11.1±0.9 | 1.43±0.23 | t=11.17, P<0.001 |
| Contact area (μm2) | 22,448±2132 | 6117±650 | t=6.06, P=0.001 | |
| Shear stress (kPa) | 518.5±48.9 | 233.0±28.6 | t=3.72, P=0.010 | |
| Accumulated secretion | Force (mN) | 5.53±0.94 | 1.62±0.24 | t=3.91, P=0.008 |
| Contact area (μm2) | 20,626±1786 | 13,389±1105 | t=3.04, P=0.023 | |
| Shear stress (kPa) | 293.8±63.9 | 134.9±31.0 | t=2.03, P=0.089 | |
| Adhesion | ||||
| Little secretion | Force (mN) | 1.78±0.27 | 0.17±0.09 | t=5.71, P=0.001 |
| Accumulated secretion | Force (mN) | 1.05±0.08 | 0.21±0.09 | t=6.85, P<0.001 |
Forces were measured for immobilised pads in the `little' and `accumulated'secretion regimes. Values are means ± s.e.m.