Jumping mechanisms and strategies in moths (Lepidoptera)

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Analysis of the kinematics of take-off in the planthopper Proutista moesta (Hemiptera, Fulgoroidea, family Derbidae) from high-speed videos showed that these insects used two distinct mechanisms involving different appendages. The first was a fast take-off (55.7% of 106 take-offs by 11 insects) propelled by a synchronised movement of the two hind legs and without participation of the wings. The body was accelerated in 1 ms or less to a mean take-off velocity of 1.7 m s −1 while experiencing average forces of more than 150 times gravity. The power required from the leg muscles implicated a poweramplification mechanism. Such take-offs propelled the insect along its trajectory a mean distance of 7.9 mm in the first 5 ms after take-off. The second and slower take-off mechanism (44.3% of take-offs) was powered by beating movements of the wings alone, with no discernible contribution from the hind legs. The resulting mean acceleration time was 16 times slower at 17.3 ms, the mean final velocity was six times lower at 0.27 m s −1 , the g forces experienced were 80 times lower and the distance moved in 5 ms after take-off was 7 times shorter. The power requirements could be readily met by direct muscle contraction. The results suggest a testable hypothesis that the two mechanisms serve distinct behavioural actions: the fast take-offs could enable escape from predators and the slow take-offs that exert much lower ground reaction forces could enable take-off from more flexible substrates while also displacing the insect in a slower and more controllable trajectory.Comparison of take-off performance using two mechanisms: (1) fast take-off propelled by hind legs and (2) slow take-off propelled by wings. Data in columns 2-6 are the grand means (±s.e.m.) for the measured jumping performance of all insects analysed. The values in columns 7-12 are calculated from these means. N=number of individuals performing this type of take-off. The best performance is based on the take-off with the highest velocity. 6

Section: Introductionmentioning

confidence: 99%

Effectiveness and efficiency of two distinct mechanisms for take-off in a derbid planthopper insect

Burrows

Ghosh

Yeshwanth

et al. 2018

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“…This mechanism is found in insects such as mantises (Burrows et al, 2015), bush crickets (Burrows and Morris, 2003), flies (Hammond and O'Shea, 2007; Trimarchi and Schneiderman, 1995; Zumstein et al, 2004) and moths (Burrows and Dorosenko, 2015). The mechanical principles underlying these jumps are similar to those used by humans and other vertebrates (Zajac, 1993; Alexander, 1995).…”

Section: Introductionmentioning

confidence: 99%

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

Sutton

Doroshenko

Cullen

et al. 2016

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Many insects such as fleas, froghoppers and grasshoppers use a catapult mechanism to jump, and a direct consequence of this is that their take-off velocities are independent of their mass. In contrast, insects such as mantises, caddis flies and bush crickets propel their jumps by direct muscle contractions. What constrains the jumping performance of insects that use this second mechanism? To answer this question, the jumping performance of the mantis Stagmomantis theophila was measured through all its developmental stages, from 5 mg first instar nymphs to 1200 mg adults. Older and heavier mantises have longer hind and middle legs and higher take-off velocities than younger and lighter mantises. The length of the propulsive hind and middle legs scaled approximately isometrically with body mass (exponent=0.29 and 0.32, respectively). The front legs, which do not contribute to propulsion, scaled with an exponent of 0.37. Take-off velocity increased with increasing body mass (exponent=0.12). Time to accelerate increased and maximum acceleration decreased, but the measured power that a given mass of jumping muscle produced remained constant throughout all stages. Mathematical models were used to distinguish between three possible limitations to the scaling relationships: first, an energylimited model (which explains catapult jumpers); second, a powerlimited model; and third, an acceleration-limited model. Only the model limited by muscle power explained the experimental data. Therefore, the two biomechanical mechanisms impose different limitations on jumping: those involving direct muscle contractions (mantises) are constrained by muscle power, whereas those involving catapult mechanisms are constrained by muscle energy.

“…Many true flies (Diptera), however, use their middle legs (Card, 2012), which are no longer than the other two pairs of legs. For some insects, a further variation to this mechanism is to use the middle and hind pairs of legs together; examples are lacewings (Neuroptera, Chrysopidae) (Burrows and Dorosenko, 2014), caddis flies (Trichoptera) (Burrows and Dorosenko, 2015b), moths (Lepidoptera) (Burrows and Dorosenko, 2015a), praying mantises (Mantodea, Mantidae) (Sutton et al, 2016) and ants (Hymenoptera) (Baroni Urbani et al, 1994;Tautz et al, 1994). Effects of this are to distribute the forces applied to the substrate over a larger area and to increase muscle mass to reduce the power requirements per unit of muscle.…”

Section: Introductionmentioning

confidence: 99%

“…The synchronisation between the leg movements does not have to be closely controlled, so that in different jumps one pair of legs may move first and one pair may leave the ground before the other. In some winged insects, propulsive leg movements can also be accompanied by the start of flapping movements of the wings, for example, in moths (Burrows and Dorosenko, 2015a), and even if the wings are not moved, their shape can influence stability of the trajectory in whiteflies (Ribak et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Jumping and take-off in a winged scorpion fly (Mecoptera, Panorpa communis)

Burrows

2019

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High-speed videos were used to analyse whether and how adults of a winged species of scorpion fly (Mecoptera, Panorpa communis) jump and determine whether they use the same mechanism as that of the only other mecopteran known to jump, the wingless snow flea, Boreus hyemalis. Adult females are longer and heavier than males and have longer legs, but of the same relative proportions. The middle legs are 20% longer and the hind legs 60% longer than the front legs. A jump starts with the middle and hind legs in variable positions, but together, by depressing their coxo-trochanteral and extending their femoro-tibial joints, they accelerate the body in 16-19 ms to mean take-off velocities of 0.7-0.8 m s −1 ; performances in males and females were not significantly different. Depression of the wings accompanies these leg movements, but clipping them does not affect jump performance.Smooth transition to flapping flight occurs once airborne with little loss of energy to body rotation. Ninety percent of the jumps analysed occurred without an observable stimulus; the remaining 10% were in response to a mechanical touch. The performance of these jumps was not significantly different. In its fastest jumps, a scorpion fly experiences an acceleration of 10 g, expends 23 µJ of energy and requires a power output less than 250 W kg −1 of muscle that can be met by direct muscle contractions without invoking an indirect power amplification mechanism. The jumping mechanism is like that of snow fleas.