Role of locust Locusta migratoria manilensis claws and pads in attaching to substrates

Abstract

The present study attempts to investigate the role of rigid claws and smooth adhesive pads in the locust Locusta migratoria manilensis, when attaching to various substrates. We measured the attachment forces on sandpaper and silicate glass plate of locusts with intact attachment system, and those with either the pretarsal claws or the tarsal pads having been entirely destroyed, to explore the role of pads and claws when a locust is walking on various substrates. To obtain information about morphological characteristics and material properties of the claws, we examined the intact and fractured claws by scanning electron microscopy, and tested the fractural force in a fracture experiment. We proposed a mechanical model for locust climbing on a slanting surface to analyze the conduction and final result of the attachment forces generated by the attachment organs on the fore-, mid-and hindlegs. Attachment forces generated by locusts with destroyed pads were similar to those generated by locusts with intact attachment system on both substrates, which presumably indicated that the claws have a significantly important role when attaching to various substrates. The result of the fracture experiment demonstrated that the claws are made of relatively stiff material, and their shear strength ranged between 39-45 MPa. Mechanical analysis of locust climbing on slanting surface showed that the force generated by the hindlegs suspended the whole body of locust up from the surface and pushed the body forward, while the midlegs steadily suspended the centre of gravity and the forelegs pulled the suspended body forward. The results obtained contribute to the further interpretation of the interaction mechanisms between insect attachment system and substrates, and supply information for designing and manufacturing slippery plates for trapping plague locusts. locust, pads, claws, attachment force, mechanical model Citation:Wang L X, Zhou Q, Xu S Y. Role of locust Locusta migratoria manilensis claws and pads in attaching to substrates.

Friction Force of Locust Locusta migratoria manilensis (Orthoptera, Locustidae) on Slippery Zones of Pitchers from Four Nepenthes Species

“…Several surfaces were cut from the slippery zones of the four Nepenthes species, after being connected to a tested surface (area is 10-16 cm 2 ) with double-sided adhesive tape, the surface was put on the platform. Following a similar method previously introduced in detail [8,9], experimental locust was attached to the force sensor (along the load direction) by means of thin thread (about 10-cm long) fastened to the locust neck, and then was put on the tested surface (Fig. 1a).…”

Effect of surface roughness on attachment ability of locust Locusta migratoria manilensis

“…Pad and claw of locust have been confirmed as potentially serving different role during attachment or locomotion. Attachment force measurement exhibited that the claw contributes a more significant responsibility, whereas the pad undertakes a supplementary function [20,30]. Consequently, the difference of locust friction force can be attributed to the influence of surface roughness on rigid claw and adhesive pad, possibly the claw undergoes more conspicuous effect.…”

“…1a). Referring to a similar method previously described [15,[20][21][22][23], the locust was connected to the force sensor (along the load direction) utilizing a thin thread (length approx. 15 cm) fastened its neck position, and then put on the selected substrate (Fig.…”

“…Previous experiments have exhibited several interesting phenomena about the locust pads, such as the mechanism of their attachment to substrates, the chemical composition and physical property of their secretions, and the measurement of adhesion force on substrates [17][18][19]. Force measurements and mechanical analyses have confirmed that claws serve a significantly important role, whereas pads display a supplementary function when locust is standing or locomoting on substrates [20]. Compared with artificial substrates, some plants can obviously decrease the locust attachment force via restricting the normal function of attachment organ, and this strong reduction results from the specialized surface architecture of plant epicuticular [21].…”

Walking on smooth and rough ground: activity and timing of the claw retractor muscle in the beetlePachnoda marginata peregrina(Coleoptera, Scarabaeidae)

“…The role of claws in attachment on different flat substrates with different microroughness was previously studied in the African rose chafer, Pachnoda marginata (Dai et al, 2002), and the migratory locust Locusta migratoria manilensis (Wang et al, 2011). Both studies indicate a strong involvement of claws in attaching to certain surface roughnesses.…”