Jumping in a wingless stick insect,Timema chumash(Phasmatodea,Timematodea, Timematidae)

Abstract

SUMMARYThe stick insect Timema chumash belongs to a sub-order of the phasmids that is thought to have diverged early from other stick insects, and which is restricted to the southwest of North America. It jumps by rapidly extending the tibiae of both its hind legs simultaneously from an initially fully flexed position, unlike any other stick insect that has been described. The hind legs are 1.5 times longer than the front and middle legs, but still represent only half the length of its body, and the femoro-tibial joints show few specialisations for jumping. In its best jumps, the wingless body is accelerated in 12·ms to a take-off velocity of 0.9·m·s -1 and experiences an acceleration of 75·m·s -2 , the equivalent of 8·g. This performance requires an energy expenditure of 19·J, generates a power output of 1.6·mW and exerts a force of 3.6·mN. The jump propels the body forward a distance of 80·mm from a mean take-off angle of 39°. Heights of 20·mm were also achieved. Elevation of the jump was controlled by the initial position of the hind legs; when the hind tibiae and femora projected above the dorsal outline of the body the jump was forwards, when parallel with the long axis of the body the jump was backwards and could result in somersaulting. The jumping movements would appear to displace Timema in different directions away from a potential predator. Supplementary material available online at

Surface tension propulsion of fungal spores

“…In both insects and vertebrates, the velocity of the center of mass is known to increase monotonically during the active part of the jump up to the take-off velocity (Burrows, 2006;Burrows, 2008;Marsh and Johnalder, 1994). The evolution of the center of mass velocity can be accounted for if a finite force is applied during the entire hind limb deployment.…”

Jumping mechanisms and performance in beetles. I. Flea beetles (Coleoptera: Chrysomelidae: Alticini)

“…The kinematic parameters in jumping insects, e.g. fleas, grasshoppers, froghoppers, planthoppers, leafhoppers, shore bugs, stick insects and snow fleas, vary in a broad range (values are given from minimum to maximum): take-off time 0.7-14.9 ms, velocity 0.5-5.5 m s −1 , acceleration 36-7000 m s −2 , kinetic energy 0.4-11,000 µJ, g-force 4-719 (from Burrows, 2006aBurrows, ,b, 2007aBurrows, , 2008Burrows, , 2009aBurrows, ,b, 2011Burrows and Morris, 2003;Burrows and Picker, 2010;Sutton and Burrows, 2011). As follows from Table 1, the kinematic parameters of flea beetles are comparable with those of other jumping insects.…”

“…specialized sclerites or various projections of the cuticle on the limbs or body) preventing the springs from premature recoiling (Burrows, 2006b). The jumping apparatus is so effective that it allows the insects to perform a jump at a distance that greatly exceeds its body length (up to 289 times), is at high velocity (up to 5.5 m s −1 ) and acceleration (from 70 to about 7000 m s −2 ), has a very short time to take-off (0.8-14 ms) and has a high g-force (up to 700 in the best jumpers; Brackenbury and Wang, 1995;Burrows, 2006aBurrows, , 2007aBurrows, , 2008Burrows, , 2009aBurrows, ,b, 2011Burrows and Morris, 2003;Schmitt, 2004;Burrows and Picker, 2010;Sutton and Burrows, 2011). This mechanism is a characteristic of insect orders as diverse as grasshoppers and locusts (Orthoptera) (Bennet-Clark, 1975;Burrows, 1995;Heitler, 1974; see 'How Grasshoppers Jump' by W. J. Heitler, http://www.st-andrews.ac.uk/~wjh/jumping/index.…”

“…html), and fleas (Siphonaptera) (Bennet-Clark and Lucey, 1967;Sutton and Burrows, 2011), and occurs in some groups of Hemiptera like leafhoppers (Cicadellidae) (Burrows, 2007b), froghoppers (Cercopoidea) (Gorb, 2004;Burrows, 2006b), planthoppers (Fulgoridae) (Burrows, 2009b) and shore bugs (Heteroptera: Saldidae) (Burrows, 2009a). It is also known to stick insects (Phasmatodea: Timematidae) (Burrows, 2008) and snow fleas (Mecopera: Boreidae) (Burrows, 2011).…”

Jumping strategies and performance in shore bugs (Hemiptera, Heteroptera,Saldidae)

“…The propulsion for jumping in insects is typically provided by rapid movements of the legs, or less often by movements of other parts of the body, all involving extensive mechanical, muscular or neural specializations to accomplish this demanding form of locomotion. Accomplished exponents, which propel jumping by rapid movements of their hind legs, are found in the Siphonaptera, fleas (Bennet-Clark and Lucey, 1967;Rothschild et al, 1972); Orthoptera, bush crickets (Tettigonidae) (Burrows and Morris, 2003) and locusts (Acrididae) (Bennet-Clark, 1975;Godden, 1975;Heitler, 1977;Heitler and Burrows, 1977a;Heitler and Burrows, 1977b); Coleoptera, flea beetles (Alticinae) (Brackenbury and Wang, 1995); and Phasmatodea, stick insects (Burrows, 2008). By contrast, in the Collembola, springtails jump by rapidly extending their terminal abdominal appendages (Brackenbury and Hunt, 1993), whereas movements of the whole abdomen are used in the Hymenoptera by some ants (Baroni et al, 1994;Tautz et al, 1994), in the Phasmatodea by a stick insect (Burrows and Morris, 2002) and in the Archaeognatha by Petrobius (Evans, 1975).…”