Table 2. Summary of launch parameters of the identified shooting mechanisms in plants.
For the projectile mass, launch velocity, launch acceleration, launch distance, and launch angle, the measurement technique is coded as following: Standard = measured using a high-speed video camera.Bold = calculated by referred authors using measured launch parameters. Italics = manual measurement of the parameter (e.g. from photograph stills, without the use of a high-speed video camera). Underlined = calculated by referred authors using a mathematical model of the shooting mechanism. Standard* = estimated by us from data/figure in indicated reference(s); for the power output per unit mass the launch acceleration [m/s2] is multiplied with the launch velocity [m/s] and for the work per unit mass the power output [W/kg] is integrated over the launch duration [s]. Bold* = calculated by us using the mean of the parameter ± 3 standard deviations. The launch parameters are indicated as mean (± standard deviation), peak (indicated with “peak” behind the value), or a range (minimum value–maximum value). Per launch parameter, the peak value identified in this review is indicated by a double-lined box (with the exception of the launch angle).
| Plants | Projectile mass [mg] | Launch acceleration [g] | Launch velocity [m/s] | Launch distance [m] | Launch angle [°] | Power output [W/kg] | Launch duration [ms] | Work [J/kg] |
|---|---|---|---|---|---|---|---|---|
| Osmosis: Water Absorption | ||||||||
| Elastic Energy Storage—Fracture Release Mechanism | ||||||||
| Fluid Pressure Catapult | ||||||||
| Arceuthobium [53,65–68] | - | - | 0.1–0.2* | - | ||||
| Arceuthobium americanum [67] | 2.0 | - | 26.1 ± 0.2 | - | - | - | - | - |
| Arceuthobium cyanocarpum [67] | 0.9 | - | 21.3 ± 0.3 | - | - | - | - | - |
| Arceuthobium cryptopodum [67,68] | 2.3 | - | 25.4 ± 0.3 | 14.6 peak | - | - | - | - |
| Arceuthobium douglasii [67] | - | - | 22.3 ± 0.4 | - | - | - | - | - |
| Arceuthobium vaginatum [65] | - | ~ 4,791 | ~ 13.7 | 4.6 | - | - | ~ 0.44 | - |
| Swelling Coiling Catapult | ||||||||
| Impatiens | ||||||||
| Impatiens capensis [69] | 10.7 ± 0.4 (7.7–19.7) | - | 1.24 ± 0.14 (4.1 peak) | 1.75 peak | 17.4 ± 5.2 | - | 4.2 ± 0.4 | - a |
| Impatiens glandulifera [70,71] | 20.7 (8.8–38.3) | - | 6.19 (2.57–12.4) | 0–10 | 47.8 (-37.1–79.7) | - | - | - |
| Cornus canadensis [72,73] | 0.024 | 2,446 ± 612 | 3.1 ± 0.5 | 0.025 (0.022–0.027) | 70–90* | 7.3·104 * (1.9·105 peak*) | 0.5 | 36.5 (95 peak)* |
| Morus alba [74] | - | 2,500 peakb | 170–237b | - | 0–180* | 2.6·105 (5.81·106 peak*) | ≤0.025 | ≤6.5 (≤145.3 peak*) |
| Osmosis: Water Evaporation | ||||||||
| Elastic Energy Storage—Fracture Release Mechanism | ||||||||
| Drying Coiling Catapult | ||||||||
| Brassicaceae | ||||||||
| Cardamine | ||||||||
| Cardamine parviflora [75,76] | 0.15 ± 0.09 | - | 6.29 ± 2.73 | 0.94 ±0.46 | 52.2 ± 23.9 | 1.9·104 * (2.64·105 peak*)c | 4.7 ± 1.3 | 89.3 ± 40.5 |
| Fabaceae | ||||||||
| Cytisus multiflorus [77] | - | - | - | 4 peak | - | - | - | - |
| Tetraberlinia moreliana [78] | 2,530 | - | 37.1 | 60 peak | 17.3 ± 11 | - | - | - |
| Acanthaceae | ||||||||
| Ruellia simplex [81] | 1.78 | - | - | 2–3 | 40 | - | - | - |
| Geraniaceae | ||||||||
| Geranium [62] | ||||||||
| Geranium carolinianum | 3.5 ± 0.3 | - | - | 3.29 ± 0.7 | 45.5 ± 3.1 | - | - | - |
| Geranium maculatum | 6 ± 0.9 | - | - | 3.02 ± 0.76 | 47.3± 10.0 | - | - | - |
| Geranium molle | 1.1 ± 0.1 | - | - | 1.79 ± 0.43 | 61.2 ± 2.1 | - | - | - |
| Erodium | ||||||||
| Erodium cicutarium [82] | 5 ± 1 | - | 4 ± 2d | 0.51 ± 0.08 | 40 ± 30 | - | - | -e |
| Drying Squeeze Catapult | ||||||||
| Euphorbiaceae | ||||||||
| Hura crepitans [8,79,84] | 1,020 (700–1,430) | - | 43 (14–70) | 30 (45 peak) | 34.2 (20–48) | - | 0.01–0.035* | - |
| Mercurialis annua [83] | 0.7–3.6 | - | - | 0.41 ± 0.31 (1.3 peak) | - | - | - | - |
| Rutaceae | ||||||||
| Metrodorea nigra [85] | - | - | - | - | - | - | - | - |
| Illicium | ||||||||
| Illicium floridanum [86] | 45 ± 4 (50 peak) | - | - | 2.5 ± 1.4 (5.8 peak) | 40–60 | - | - | - |
| Oxalis acetosella [87] | 0.9 (0.3–1.5) | - | - | 2 peak | - | - | - | - |
| Viola [62,88] | ||||||||
| Viola blanda | - | - | - | 1 (0.1–3.8) | - | - | - | - |
| Viola curcullata | - | - | - | 1.5 (0.1–2.1) | - | - | - | - |
| Viola eriocarpa | 6 ± 0.9 | - | - | 1.2 (0.2–5.4) | 67.5 ± 14.5 | - | - | - |
| Viola papilionacea | - | - | - | 2.1 (0.05–4.8) | - | - | - | - |
| Viola pedata | - | - | - | 1.4 (0.25–5.1) | - | - | - | - |
| Viola rostrata | - | - | - | 1.2(0.1–4.2) | - | - | - | - |
| Viola striata | 1.1 ± 0.2 | - | - | 1.5 (0.4–3) | - | - | - | - |
| Air Pressure Catapult | ||||||||
| Sphagnum [1,33,89,90] | - | - (36,697 peak) | 16 (30 peak) | 0.15 (0.1–0.2) | 80–90* | -(1.08·107 peak*) | 0.01 | - (108 peak*)f |
| Elastic Energy Storage—Cavitation Release Mechanism | ||||||||
| Cavitation Coiling Catapult | ||||||||
| Polypodiaceae (common ferns) [94,95] | ||||||||
| Polypodium aureum [94,95] | - | ~ 100,000 | 10 | 0.01–0.02 | - | 9.81·106 * | ≤ 0.01 | ≤ 98.1* |
| Adiantum peruvianum [93] | - | 6,320 at 3.1 m/s | 2.4 ± 1 (5.0 peak) | 0.057 peak* | - | 1.48·105 (3.09·105 peak)* | 0.01* | 1.48 (3.09 peak)* |
| Selaginella | ||||||||
| Selaginella martensii [96] | - | - | - (0.6)g | 0.01–0.06g | - | - | < 1 | - |
a Stored elastic energy: 8.87 J (efficiency of 0.5%) [69]
b Average angular velocity: 69,800 rad/s and peak angular acceleration: 5·106 rad/s2 [74]
c Mean estimated stored energy: 0.482 ± 0.219 J (21.3 ± 10.3% efficiency) [75]
d Initial angular velocity: 200 ± 100 rad/s [82]
e Estimated released elastic energy: 2.72·10−3 J [82]
f Energy stored in the compressed air: 0.27 mJ [1]