QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online October 7, 2008
Journal of Experimental Biology 211, 3333-3343 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.020941

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bullock, J. M. R. Articles by Federle, W. Search for Related Content PubMed PubMed Citation Articles by Bullock, J. M. R. Articles by Federle, W. Social Bookmarking                         What's this?

Comparison of smooth and hairy attachment pads in insects: friction, adhesion and mechanisms for direction-dependence

James M. R. Bullock, Patrick Drechsler and Walter Federle^*

Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK

^* Author for correspondence (e-mail: wf222{at}cam.ac.uk)

Accepted 19 August 2008

Adhesive pads on the legs of animals can be classified as either `smooth' or `hairy' (fibrillar). It has been proposed that the hairy design conveys superior and controllable adhesion. However, no study has yet compared the basic performance of both systems. As such, we measured single-pad friction and adhesion forces in sample hairy (Gastrophysa viridula) and smooth (Carausius morosus) pads and simultaneously recorded contact area. Adhesion and friction forces per unit pad area were very similar in smooth and hairy systems. Insect pads of both types adhere via a thin film of liquid secretion. As found previously for the smooth system, forces in the fibrillar system strongly decreased with larger amounts of fluid secretion present, suggesting that the fluid mainly serves to maximize contact on rough substrates. One essential prerequisite for the control of surface attachment during locomotion is the direction-dependence of adhesive pads. We compared the mechanisms of direction-dependence in smooth and hairy systems by performing proximal and distal slides. Both types of pad exhibited a large drop in friction when moved away from the body, although this effect was more extreme for the hairy system. Direction-dependence is explained in both smooth and fibrillar systems by the instability of the tarsal chain, causing the whole pad to peel off. In the fibrillar pads, anisotropy additionally arises from the direction-dependence of individual setae.

Key words: adhesion, biomechanics, direction-dependence, locomotion, tribology

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				C. J. Clemente, J. M. R. Bullock, A. Beale, and W. Federle Evidence for self-cleaning in fluid-based smooth and hairy adhesive systems of insects J. Exp. Biol., February 15, 2010; 213(4): 635 - 642. [Abstract] [Full Text] [PDF]

				N. Gravish, M. Wilkinson, S. Sponberg, A. Parness, N. Esparza, D. Soto, T. Yamaguchi, M. Broide, M. Cutkosky, C. Creton, et al. Rate-dependent frictional adhesion in natural and synthetic gecko setae J R Soc Interface, February 6, 2010; 7(43): 259 - 269. [Abstract] [Full Text] [PDF]

				J. M. R. Bullock and W. Federle Division of labour and sex differences between fibrillar, tarsal adhesive pads in beetles: effective elastic modulus and attachment performance J. Exp. Biol., June 15, 2009; 212(12): 1876 - 1888. [Abstract] [Full Text] [PDF]