Jumping up a level: Target distance and angle estimation facilitates successful landing in a jumping glass katydid

Abstract

Jumping is one of the most used forms of locomotion by insects, and a characteristic trait of the Orthoptera (locusts, crickets, and allies). Their specialized jumping behaviors have evolved for various functions, including travel, predator evasion, and flight initiation. While these jumping behaviors have been studied, targeted jumps required for navigating complex environments and hunting have received little attention. Here, we document a vertical jumping behavior in a species of neotropical predatory bush cricket (Phlugis cf. celerinicta. Tettigoniidae: Meconematinae), which uses visual cues to estimate target distance. Jumping kinematics were adjusted between jump heights (50mm, 75mm, and 100mm), with an increase in linear velocity and decrease in angular velocity at higher target heights. Body and leg postures also varied between jump heights. This study provides evidence that P. celerinicta can independently control both the speed at take-off and rotation rate based on target distance to achieve a precise and controlled landing.

Keywords: Biomechanics; Entomology; Zoology.

Graphical abstract

Figure 1

Simple illustration of a beam model depicting an insect prior to take-off This illustrates incrementally simpler models of an insect jumping to calculate the relationship between linear and angular velocity if each jump starts from an identical body position. (A) A mechanical sketch of the insect. (B) A simplified sketch modeling the head and thorax as a rectangular prism, with the muscle force in the legs acting as a torque, T, in the femorotibial joint (FTJ) (similar to the model in¹³). (C) A further simplified sketch modeling the force from the legs, F, applied at a distance, l, from the center of mass. The rectangular prism has a length L, and a mass m.

Figure 2

Jump progression stills and the resulting kinematics at take-off (A) Compilation of a series of still images of the jump progression of the Phlugis celerinicta at 50 mm, 75 mm and 100 mm (left to right) from at rest (indicated by ∗ in the photograph), during take-off (indicated by ∗∗) and at landing (indicated by ∗∗∗), filmed at 2,000 frames per second. (B) Mean (±SE) linear velocity (m·s⁻¹; blue circles) and angular velocity (rad·s⁻¹; red triangles) of the jumps at different jump heights (note the differences in the Y axes).