The green leafhopper,Cicadella viridis(Hemiptera, Auchenorrhyncha, Cicadellidae), jumps with near-constant acceleration

Abstract

SUMMARY Jumping insects develop accelerations that can greatly exceed gravitational acceleration. Although several species have been analysed using different tools, ranging from a purely physical to a morpho-physiological approach, instantaneous dynamic and kinematic data concerning the jumping motion are lacking. This is mainly due to the difficulty in observing in detail events that occur in a few milliseconds. In this study, the behaviour of the green leafhopper, Cicadella viridis, was investigated during the take-off phase of the jump, through high-speed video recordings (8000 frames s−1). We demonstrate that C. viridis is able to maintain fairly constant acceleration during overall leg elongation. The force exerted at the foot–ground interface is nearly constant and differs from the force expected from other typical motion models. A biomechanical model was used to highlight that this ability relies on the morphology of C. viridis hind legs, which act as a motion converter with a variable transmission ratio and use the time-dependent musculo-elastic force to generate a nearly constant thrust at the body–ground interface. This modulation mechanism minimizes the risk of breaking the substrate thanks to the absence of force peaks. The results of this study are of broad relevance in different research fields ranging from biomechanics to robotics.

Take-off speed in jumping mantises depends on body size and a power limited mechanism

“…In fleas and leafhoppers, their morphology may keep acceleration constant before take-off (Sutton and Burrows, 2011; Bonsignori et al, 2013), and this model, which predicts a slope of 1/6, reflects that possible constraint. Take-off velocity was estimated by setting the acceleration at the mean value of the average acceleration for all observed jumps, 29.8±6.2 m s −2 ( N =50).…”

“…In jumping insects, the acceleration is approximately constant (Bonsignori et al, 2013; Sutton and Burrows, 2011), which allows Eqn 6 to be solved for the take-off time: …”

“…Another possibility has been raised by the consideration of acceleration during the jump by an insect (Sutton and Burrows, 2011; Bonsignori et al, 2013). In these two studies, the forces within the joints decreased at approximately the same rate as the moment arms increased, resulting in nearly constant joint torques and, by extension, accelerations during the jump.…”

Lateralisation of aggressive displays in a tephritid fly

“…Male-male and femalefemale contests were recorded with the HotShot 512 SC highspeed video camera (NAC Image Technology Inc., Simi Valley, CA, USA). Sequential images from each aggression were captured at a rate of 2000 frames per second (fps) with an exposure time of 0.5 ms and a video duration of 4.1 s. The HotShot 512 SC video camera stored images with a resolution of 512×512 pixels directly to its internal memory (Bonsignori et al 2013). These images were downloaded into a dedicated computer for data analysis.…”

Analysis of the structural behaviour of colonic segments by inflation tests: Experimental activity and physio-mechanical model

“…After the creep step, the sample was deflated. In total, 16 inflation tests were performed on each experimental sample according to different inflated top pressures, such as 4, 6,8,10,14,18,22,26,30,34,38,46, 54, 62, 70 and 78 mmHg. The pressure range of experimentations, such as 4-78 mmHg, and the pressure rate were identified by preliminary inflation tests that were developed on further colon samples.…”