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

Abstract

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

What goes up must come down - biomechanical impact analysis of falling locusts

“…In particular, the orientation (and thus air resistance) of the legs could be an additional factor determining falling speed. This effect has previously been indicated by studies on falling insects (Faisal and Matheson (2001) and take-off of jumping insects (Burrows et al, 2019). Our video recordings show that both active and inactive locusts often had their hind legs stretched out (see Movie 2), which might increase air resistance.…”

“…As the wings presumably play an important role in the air-righting behavior during take-off (Burrows et al, 2019) and landing of insects (Faisal and Matheson, 2001), one explanation could well be that falling active locusts actively use their wings to steer (gain control). Indeed, locusts with wings were able to control their impact angle during free fall, whilst wingless locusts landed at almost the same impact angle they had been dropped with (see Fig.…”

“…Although the initial trajectory of the take-off and even the orientation of the body might be controlled by several jumping insect species (Burrows et al, 2019;Burrows, 2008, 2011;Faisal and Matheson, 2001;Rothschild et al, 1972;Alexander, 1995;Heitler, 1974), external factors such as gusts of wind or unforeseen obstacles make it extremely difficult to reliably predict the mechanical properties of the landing site (Bennet-Clark and Alder, 1979). An insect landing after a jump thus must be able to cope with a large variety of possible surface properties.…”

Takeoff diversity in Diptera

“…These are modified hindwings that act as gyroscopes, sensing body rotations [2][3][4][5] and as metronomes, sending timing information to the wings [6,7]. The contribution of wing and leg muscles in determining takeoff strategy is well established [8][9][10][11][12][13][14], but the role of halteres during takeoff has not been examined. The halteres may be providing critically timed neural input that is needed to coordinate the wings and legs to generate the directed power necessary for takeoff, which results from a combination of leg and wing movements that can vary by species [13][14][15] or context [16,17].…”

Jumping in lantern bugs (Hemiptera, Fulgoridae)

“…This pattern suggests that there may be limitations on the performance of PADT and FT jumping mechanisms based on size. We were therefore fortunate to obtain specimens of Lantern bugs, (Fulgoroidea, family Fulgoridae) which have masses 20-600× heavier than previously studied planthoppers (e.g Burrows et al, 2019) or froghoppers (Burrows, 2006) in which for the first time we can compare the performance of large insects with a PADT jumping mechanism with smaller members of the group. The planthoppers or Fulgoroidea (=Fulgoromorpha) are a group of twenty one families within the Auchenorrhyncha which share many common morphological features (Cryan and Urban, 2011;Skinner et al 2019), amongst which is a hind leg-movement synchronising mechanism based on interlocking gears on their hind trochantera as nymphs (Burrows and Sutton, 2013;Siwanowicz and Burrows, 2017).…”