Jump of the Oriental Rat Flea Xenopsylla cheopis (Roths.)

Hartung

Hoch

2007

SUMMARY Jumping by a relict insect, Hackeriella veitchi (Hacker 1932),belonging to the ancient Coleorrhynchan line that diverged from other Hemiptera in the late Permian, was analysed from high-speed images captured at rates of 2000 s–1 and from its anatomy. This 3 mm long,flightless insect weighs up to 1.4 mg and can jump by rapid movements of the hind legs that accelerate the body in 1.5 ms to a take-off velocity of 1.5 m s–1. This performance requires an energy expenditure of 1.1μJ and a power output 0.74 mW, and exerts a force of 1.24 mN. It achieves this with a body design that shows few specialisations for jumping compared with those of other groups of Hemipterans such as the froghoppers or leafhoppers. The hind legs are only 10% longer than the front and middle legs by virtue of longer tibiae and tarsi, and are only 65% the length of the body. The main thrust for a jump is provided by the rapid rotation of the fused trochanter and femur about the coxa of a hind leg, in a movement that forces the hind tarsus against the ground and raises the body to take off. In some jumps the two hind legs move together, but in others the movements may not be closely synchronised, thereby imparting a rotation on the body that is maintained once airborne. When the time difference is larger, the rapid movement of just one hind leg results in the insect falling from its perch in an adaptive escape response.

Section: Comparison With Other Jumping Hemipteransmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Jumping behaviour in a Gondwanan relict insect (Hemiptera: Coleorrhyncha:Peloridiidae)

Hartung

Hoch

2007

“…These studies were in agreement about how fleas stored energy for a jump, but provided two different hypotheses for how the force was transmitted to the ground. The hypothesis put forward by Rothschild et al (Rothschild et al, 1972;Rothschild et al, 1973;, henceforth called the Rothschild hypothesis, argued that the expansion of the spring pushed the hind trochanter onto the ground to transmit the force. This argument was based on two observations: first, in the preparatory phase of the jump, fleas placed their hind trochantera on the ground; second, amputation of the hind tarsi had only a small effect on the frequency of jumping.…”

Section: Introductionmentioning

confidence: 99%

“…They first lock the thoracocoxal joints of the two hindlegs and then contract two large dorsoventral muscles to compress part of the skeletal structure of the thorax that contains the elastic protein resilin, so that it acts as a tensed spring (Bennet-Clark and Lucey, 1967;Rothschild et al, 1972;Rothschild et al, 1973;. The lock on the hindlegs is then released and the rapid expansion of the spring releases the stored energy, which propels the jump (Bennet-Clark and Lucey, 1967;Rothschild et al, 1972;Rothschild et al, 1973;. These studies were in agreement about how fleas stored energy for a jump, but provided two different hypotheses for how the force was transmitted to the ground.…”

Section: Introductionmentioning

confidence: 99%

Biomechanics of jumping in the flea

Sutton

2011

114

SUMMARYIt has long been established that fleas jump by storing and releasing energy in a cuticular spring, but it is not known how forces from that spring are transmitted to the ground. One hypothesis is that the recoil of the spring pushes the trochanter onto the ground, thereby generating the jump. A second hypothesis is that the recoil of the spring acts through a lever system to push the tibia and tarsus onto the ground. To decide which of these two hypotheses is correct, we built a kinetic model to simulate the different possible velocities and accelerations produced by each proposed process and compared those simulations with the kinematics measured from high-speed images of natural jumping. The in vivo velocity and acceleration kinematics are consistent with the model that directs ground forces through the tibia and tarsus. Moreover, in some natural jumps there was no contact between the trochanter and the ground. There were also no observable differences between the kinematics of jumps that began with the trochanter on the ground and jumps that did not. Scanning electron microscopy showed that the tibia and tarsus have spines appropriate for applying forces to the ground, whereas no such structures were seen on the trochanter. Based on these observations, we discount the hypothesis that fleas use their trochantera to apply forces to the ground and conclude that fleas jump by applying forces to the ground through the end of the tibiae. Supplementary material available online at

“…To overcome the limitations of direct muscular contractions in propelling such fast but powerful movements, insects often use a catapult mechanism (Gronenberg, 1996;Patek et al, 2011). This mechanism is used by insects as diverse as fleas (Siphonaptera) (Bennet-Clark and Lucey, 1967;Rothschild et al, 1972;, froghoppers (Hemiptera, Cercopidae) (Burrows, 2003;Burrows, 2006), planthoppers (Hemiptera, Fulgoridae) (Burrows, 2009), flea beetles (Coleoptera, Chrysomelidae) (Furth et al, 1983), and grasshoppers and locusts (Orthoptera) (Bennet-Clark, 1975;Brown, 1967;Burrows, 1995;Godden, 1975;Heitler and Burrows, 1977). The jumping performance achieved by using a catapult is impressive.…”

Section: Introductionmentioning

confidence: 99%

Locusts use a composite of resilin and hard cuticle as an energy store for jumping and kicking

Sutton

2012

SUMMARYLocusts jump and kick by using a catapult mechanism in which energy is first stored and then rapidly released to extend the large hind legs. The power is produced by a slow contraction of large muscles in the hind femora that bend paired semi-lunar processes in the distal part of each femur and store half the energy needed for a kick. We now show that these energy storage devices are composites of hard cuticle and the rubber-like protein resilin. The inside surface of a semi-lunar process consists of a layer of resilin, particularly thick along an inwardly pointing ridge and tightly bonded to the external, black cuticle. From the outside, resilin is visible only as a distal and ventral triangular area that tapers proximally. High-speed imaging showed that the semi-lunar processes were bent in all three dimensions during the prolonged muscular contractions that precede a kick. To reproduce these bending movements, the extensor tibiae muscle was stimulated electrically in a pattern that mimicked the normal sequence of its fast motor spikes recorded in natural kicking. Externally visible resilin was compressed and wrinkled as a semilunar process was bent. It then sprung back to restore the semi-lunar process rapidly to its original natural shape. Each of the five nymphal stages jumped and kicked and had a similar distribution of resilin in their semi-lunar processes as adults; the resilin was shed with the cuticle at each moult. It is suggested that composite storage devices that combine the elastic properties of resilin with the stiffness of hard cuticle allow energy to be stored by bending hard cuticle over only a small distance and without fracturing. In this way all the stored energy is returned and the natural shape of the femur is restored rapidly so that a jump or kick can be repeated. Supplementary material available online at