Molecular and functional characterisation of resilin across three insect orders

2014

The jumping performance of three species of hemipterans from Australia and Europe belonging to the family Flatidae was analysed from images captured at a rate of 5000 s −1. The shape of a flatid was dominated by large triangular or wedge-shaped front wings, which, when folded, covered and extended above and behind the body to give a laterally compressed and possibly streamlined appearance. The body lengths of the three species of adults ranged from 7 to 9 mm and their mass from 8 to 19 mg. The propulsive hind legs were 30% longer than the front legs but only 36-54% of the body length. Jumps with the fastest take-off velocities of 2.8-3.2 m s −1 had acceleration times of 1.4-1.8 ms. During such jumps, adults experienced an acceleration of 174-200 g. These jumps required an energy expenditure of 76-225 μJ, a power output of 13-60 mW and exerted a force of 9-37 mN. The required power output per mass of jumping muscle in adults ranged from 24,000 to 27,000 W kg −1 muscle, 100 times greater than the maximum active contractile limit of normal muscle. The free-living nymphs were also proficient jumpers, reaching take-off velocities of 2.2 m s −1. To achieve such a jumping performance requires a power amplification mechanism. The energy store for such a mechanism was identified as the internal skeleton linking a hind coxa to the articulation of a hind wing. These pleural arches fluoresced bright blue when illuminated with UV light, indicating the presence of the elastic protein resilin. The energy generated by the prolonged contractions of the trochanteral depressor muscles was stored in distortions of these structures, and the rapid elastic recoil of these muscles powered the synchronous propulsive movements of the hind legs.

Section: Research Articlementioning

confidence: 84%

Jumping mechanisms in flatid planthoppers (Hemiptera, Flatidae)

2014

“…Snow fleas are the only example of insects thought to use a catapult mechanism distributed across four legs. In these insects, each leg has a potential site for the storage of energy associated with the presence of resilin and is located in a similar position to that used by fleas (Bennet-Clark and Lucey, 1967;Lyons et al, 2011;Sutton and Burrows, 2011). How does the performance of mirids analysed in this study compare with other insects that use the same mechanism of direct muscle contractions and with those insects that use a catapult mechanism?…”

Section: Jumping Is Propelled By Direct Muscle Contractionsmentioning

confidence: 99%

Jumping performance of flea hoppers and other mirid bugs (Hemiptera, Miridae)

Dorosenko

2017

The order Hemiptera includes jumping insects with the fastest takeoff velocities, all generated by catapult mechanisms. It also contains the large family Miridae or plant bugs. Here, we analysed the jumping strategies and mechanisms of six mirid species from high-speed videos and from the anatomy of their propulsive legs, and conclude that they use a different mechanism in which jumps are powered by the direct contractions of muscles. Three strategies were identified. First, jumping was propelled only by movements of the middle and hind legs, which were, respectively, 140% and 190% longer than the front legs. In three species with masses ranging from 3.4 to 12.2 mg, depression of the coxo-trochanteral and extension of femoro-tibial joints accelerated the body in 8-17 ms to take-off velocities of 0.5-0.8 m s . The middle legs lost ground contact 5-6 ms before take-off so that the hind legs generated the final propulsion. The power requirements could be met by the direct muscle contractions so that catapult mechanisms were not implicated. Second, other species combined the same leg movements with wing beating to generate take-off during a wing downstroke. Third, up to four wingbeat cycles preceded take-off and were not assisted by leg movements. Take-off velocities were reduced and acceleration times lengthened. Other species from the same habitat did not jump. The lower take-off velocities achieved by powering jumping by direct muscle contractions may be offset by eliminating the time taken to load catapult mechanisms.

“…Second, resilin fluorescence has reversible sensitivity to pH, which was observed here. A recently introduced resilin antibody should add a further means of identification in future studies (Burrows et al, 2011;Lyons et al, 2011).…”

Section: Is the Blue Fluorescence From Resilin?mentioning

confidence: 99%

A buckling region in locust hindlegs contains resilin and absorbs energy when jumping or kicking goes wrong

Bayley

Sutton

2012

SUMMARYIf a hindleg of a locust slips during jumping, or misses its target during kicking, energy generated by the two extensor tibiae muscles is no longer expended in raising the body or striking a target. How, then, is the energy in a jump (4100-4800J) or kick (1700J) dissipated? A specialised buckling region found in the proximal hind-tibia where the bending moment is high, but not present in the other legs, buckled and allowed the distal part of the tibia to extend. In jumps when a hindleg slipped, it bent by a mean of 23±14deg at a velocity of 13.4±9.5degms , we showed that one hindleg could store about 870J on bending, of which 210J was dissipated back to the leg on release. A band of blue fluorescence was revealed at the buckling region under UV illumination that had the two key signatures of the elastic protein resilin. A group of campaniform sensilla 300m proximal to the buckling region responded to imposed buckling movements. The features of the buckling region show that it can act as a shock absorber as proposed previously when jumping and kicking movements go wrong. Supplementary material available online at