Abstract

Plant-dwelling beetles overcome challenging attachment hurdles by means of ellaborated, tarsal attachment devices, which are frequently equipped with hairy adhesive pads. While the tarsal functional morphology has been intensively studied in leaf and ladybird beetles during the last decades, longhorn beetles (Cerambycidae) have been widely neglected in experimental studies on insect attachment. However, they are known to strongly hold on to plant substrates, using tarsi that are densely covered with adhesive setae. In the present study, we examined the Japanese pine sawyer beetle, Monochamus alternatus, which lives in an arboreal habitat, as an exemplary case. Traction force of male and female beetles on (1) flat and (2) cylindrical, rod-shaped glass was measured. The substrates are further called (1) glass plate and (2) glass rod.Both male and female M. alternatus bear ribbon-shaped tarsal adhesive setae with broadened, ultrathin terminals. They release a distinct amount of adhesion-mediating fluid after each step. The beetles never walked on the vertically oriented glass plate. However, they performed well on the horizontal plate, as well as on the horizontally and vertically oriented glass rod. Males generated higher forces and safety factors (traction force devided by the body weight) than females, reaching up to 206 mN traction force and a safety factor of 32 on the horizontal glass rod. Thus, they are able to carry their remarkable body weight (ca. 300 mg) throughout a rather long life span.We assume the adaptation of M. alternatus to the attachment on convex and rod-shaped structures to be present in its natural habitat. This longhorn beetle species achieves a proper hold through a combination of interacting parameters: appropriate body alignment and two-sided leg grasping, and generation of normal and friction forces by tarsal pads. This smart attachment system gives rise to the reconsideration of the ecological and evolutionary background, and provides insights for the development of bio-inspired technical grippers.

Highlights

  • Plant-dwelling beetles overcome challenging attachment hurdles by means of ellaborated, tarsal attachment devices, which are frequently equipped with hairy adhesive pads

  • We focused on the Japanese pine sawyer beetle, Monochamus alternatus Hope, as a model species, a member of the longhorn beetle subfamily Lamiinae, representatives of which are associated with Angiospermae [5]

  • Males performed significantly better than females, and significantly best on the horizontal glass rod (2.2 times higher value than on the glass plate)

Read more

Summary

Introduction

Plant-dwelling beetles overcome challenging attachment hurdles by means of ellaborated, tarsal attachment devices, which are frequently equipped with hairy adhesive pads. While the tarsal functional morphology has been intensively studied in leaf and ladybird beetles during the last decades, longhorn beetles (Cerambycidae) have been widely neglected in experimental studies on insect attachment. They are known to strongly hold on to plant substrates, using tarsi that are densely covered with adhesive setae. Adults disperse by walking and short-range flights in the pine canopy (7–40 m per week) [6] These beetles rely on tarsal attachment and locomotion while (1) exploring new feeding and oviposition sites, (2) feeding, (3) oviposition, (4) intraspecific competition, and (5) mating. All such activities require a proper hold, which is needed to lay eggs

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call