Wet Adhesion in Tree Frogs

2012 ◽  
pp. 2828-2828
Author(s):  
Richard P. Mann ◽  
Avinash P. Nayak ◽  
M. Saif Islam ◽  
V. J. Logeeswaran ◽  
Edward Bormashenko ◽  
...  
Keyword(s):  
Wet Adhesion ◽  
Tree Frogs

scholarly journals Adhesion and Detachment of the Toe Pads of Tree Frogs

1991 ◽  
Vol 155 (1) ◽  
pp. 103-125 ◽  
Author(s):  
GAVIN HANNA ◽  
W. JON ◽  
W. P. JON BARNES
Keyword(s):  
Vertical Surface ◽  
Natural Consequence ◽  
Shear Forces ◽  
Wet Adhesion ◽  
Viscous Forces ◽  
Osteopilus Septentrionalis ◽  
Filled Joint ◽  
Forward Locomotion ◽  
Tree Frogs ◽  
Adhesive Forces

The mechanisms by which the toe pads of tree frogs adhere to and detach from surfaces during climbing have been studied in Osteopilus septentrionalis and other tree frogs using a variety of techniques. The experiments on attachment lend general support to the theory that toe pads stick by wet adhesion. First, the presence of a meniscus surrounding the area of contact shows that pad and surface are connected by a fluid-filled joint. Second, experiments on single toe pads of anaesthetised frogs demonstrate that the pads exhibit the velocity-dependent resistance to shear forces expected of any system employing a fluid as an adhesive mechanism. Third, the largest adhesive forces that toe pads can generate (approx. 1.2mNmm−2, calculated from data on sticking ability) are within the range that can be produced by wet adhesion. Simple measurements of the forces needed to separate a pair of metal discs joined by mucus demonstrate that both viscous forces (Stefan adhesion) and surface tension (the two components of wet adhesion) are likely to play significant roles in the tree frog's adhesive mechanism. The experiments on detachment demonstrate that toe pads are detached from surfaces by peeling, the pads being removed from the rear forwards during forward locomotion up a vertical surface. When the frogs were induced to walk backwards down this vertical slope, peeling occurred from the front of the pad rearwards. Use of a force platform to measure directly the forces exerted by the feet during climbing shows that, during forward locomotion up a vertical slope, this peeling is not accompanied by any detectable detachment forces. Such forces of detachment are seen, however, during backward walking down the slope and when belly skin comes into contact with the platform. That peeling occurs automatically during forward locomotion is supported both by observations of peeling in single toe pads of anaesthetised frogs and by the inability of frogs to adhere to vertical surfaces in a head-down orientation. Indeed, frogs on a rotating vertical surface were observed to adjust their orientations back towards the vertical whenever their deviation from the vertical reached 85.1 ±21.5°. During forward locomotion peeling seems to occur as a natural consequence of the way in which the toes are lifted off surfaces from the rear forwards, while during backward locomotion it is an active process involving the distal tendons of the toes. Note: To whom requests for offprints should be send.

scholarly journals Tree frog adhesion biomimetics: opportunities for the development of new, smart adhesives that adhere under wet conditions

2019 ◽  
Vol 377 (2150) ◽  
pp. 20190131 ◽  
Author(s):  
Fandong Meng ◽  
Quan Liu ◽  
Xin Wang ◽  
Di Tan ◽  
Longjian Xue ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Science And Technology ◽  
Tree Frog ◽  
Theme Issue ◽  
Testing Hypotheses ◽  
Wet Adhesion ◽  
Reversible Adhesion ◽  
Epithelial Structure ◽  
Dry And Wet Conditions ◽  
Tree Frogs

Enlarged adhesive toe pads on the tip of each digit allow tree frogs to climb smooth vertical and overhanging surfaces, and are effective in generating reversible adhesion under both dry and wet conditions. In this review, we discuss the complexities of the structure of tree frog toe pads in relation to their function and review their biomimetic potential. Of particular importance are the (largely) hexagonal epithelial cells surrounded by deep channels that cover the surface of each toe pad and the array of nanopillars on their surface. Fluid secreted by the pads covers the surface of each pad, so the pads adhere by wet adhesion, involving both capillarity and viscosity-dependent forces. The fabrication and testing of toe pad mimics are challenging, but valuable both for testing hypotheses concerning tree frog toe pad function and for developing toe pad mimics. Initial mimics involved the fabrication of hexagonal pillars mimicking the toe pad epithelial structure. More recent ones additionally replicate the nanostructures on their surface. Finally we describe some of the biomimetic applications that have been developed from toe pad mimics, which include both bioinspired adhesives and friction-generating devices. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

scholarly journals First record of Metapolystoma (Monogenea: Polystomatidae) from Boophis tree frogs in Madagascar, with the description of five new species

2021 ◽  
Vol 14 ◽  
pp. 161-178
Author(s):  
Willem Landman ◽  
Olivier Verneau ◽  
Liliane Raharivololoniaina ◽  
Louis du Preez
Keyword(s):  
New Species ◽  
First Record ◽  
Tree Frogs

Mussel wet adhesion inspired using dopamine methacrylamide as a primer to improve dentin adhesion

2021 ◽  
pp. 1-13
Author(s):  
Li Quan-Li ◽  
Wang Qing-qing ◽  
Zhu Xiaopeng ◽  
Zhao Yuan-Cong
Keyword(s):  
Wet Adhesion

Litoria gracilenta (Anura : Hylidae) and related species in New Guinea

2004 ◽  
Vol 52 (2) ◽  
pp. 191 ◽  
Author(s):  
J. I. Menzies ◽  
M. J. Tyler
Keyword(s):  
Statistical Analysis ◽  
Related Species ◽  
New Guinea ◽  
Large Collection ◽  
Tree Frogs

We examined a large collection (n = 132) of tree frogs, hitherto identified as Litoria gracilenta, from various localities in New Guinea and compared them with Litoria gracilenta from Queensland and with the recently described Litoria elkeae from far west New Guinea. We found that the frogs in question were neither L. gracilenta nor L. elkeae but comprised two distinct taxa described herein as new species.We call attention to the problems of performing statistical analysis on measurements of soft-bodied organisms and consider that the conclusions reached in this analysis are both conservative and realistic.

Morphologic, Immunohistochemical, and Molecular Characterization of a Novel Lankesterella Protozoan in Two White's Tree Frogs (Litoria caerulea)

2010 ◽  
Vol 41 (2) ◽  
pp. 242-248 ◽  
Author(s):  
Barbara Gericota ◽  
Michael M. Garner ◽  
Bradd Barr ◽  
Robert Nordhausen ◽  
R. Scott Larsen ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Litoria Caerulea ◽  
Tree Frogs

scholarly journals Wet but not slippery: boundary friction in tree frog adhesive toe pads

2006 ◽  
Vol 3 (10) ◽  
pp. 689-697 ◽  
Author(s):  
W Federle ◽  
W.J.P Barnes ◽  
W Baumgartner ◽  
P Drechsler ◽  
J.M Smith
Keyword(s):  
Boundary Friction ◽  
Tree Frog ◽  
Force Measurements ◽  
Present Evidence ◽  
Laser Tweezer ◽  
Viscous Forces ◽  
Litoria Caerulea ◽  
Filled Joint ◽  
Tree Frogs ◽  
Close Contacts

Tree frogs are remarkable for their capacity to cling to smooth surfaces using large toe pads. The adhesive skin of tree frog toe pads is characterized by peg-studded hexagonal cells separated by deep channels into which mucus glands open. The pads are completely wetted with watery mucus, which led previous authors to suggest that attachment is solely due to capillary and viscous forces generated by the fluid-filled joint between the pad and the substrate. Here, we present evidence from single-toe force measurements, laser tweezer microrheometry of pad mucus and interference reflection microscopy of the contact zone in Litoria caerulea , that tree frog attachment forces are significantly enhanced by close contacts and boundary friction between the pad epidermis and the substrate, facilitated by the highly regular pad microstructure.

Albumin Evolution and Organismal Evolution in Tree Frogs (Hylidae)

1975 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
Linda R. Maxson ◽  
A. C. Wilson
Keyword(s):  
Tree Frogs
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