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 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.

The valid nomen for the tree frog (genus Hyla) of Tunisia and Eastern Algeria

Zootaxa ◽  
2020 ◽  
Vol 4759 (4) ◽  
pp. 597-599 ◽  
Author(s):  
CHRISTOPHE DUFRESNES ◽  
PIERRE-ANDRÉ CROCHET
Keyword(s):  
Mediterranean Basin ◽  
Western Mediterranean ◽  
Northern Italy ◽  
Tree Frog ◽  
Rad Sequencing ◽  
Western Mediterranean Basin ◽  
Genome Wide ◽  
Genome Wide Data ◽  
Tree Frogs ◽  
Eastern Algeria

Mediterranean tree frogs, Hyla gr. meridionalis Boettger, 1874 (Anura: Hylidae) are widespread around the Western Mediterranean Basin, where they naturally occur across the Maghreb (Morocco, Algeria, Tunisia). Individuals of diverse Moroccan origins have been introduced and have expanded throughout the Iberian Peninsula, southern France and northern Italy (Liguria), but also on the Canary and Balearic archipelagos (Recuero et al. 2007; Dufresnes et al. 2019). Early molecular studies uncovered several mitochondrial lineages and suggested a major cryptic diversification within this taxon, with Tunisian and eastern Algerian (Numidia) populations carrying deeply divergent haplotypes compared with the rest of the range (Recuero et al. 2007; Stöck et al. 2008; Stöck et al. 2012). While intron markers showed little differentiation (Stöck et al. 2008; Stöck et al. 2012), genome-wide data obtained from RAD-sequencing have supported the deep split suspected from mtDNA (Dufresnes et al. 2018). 

scholarly journals Bioinspired triangular patterns for water collection from fog

2019 ◽  
Vol 377 (2150) ◽  
pp. 20190128 ◽  
Author(s):  
Dong Song ◽  
Bharat Bhushan
Keyword(s):  
Pressure Gradient ◽  
Science And Technology ◽  
Laplace Pressure ◽  
Theme Issue ◽  
Droplet Motion ◽  
Triangular Shape ◽  
Conical Shape ◽  
Bioinspired Materials ◽  
Water Collection ◽  
Curvature Gradient

Cacti use spines with conical geometry to transport water to its base. A conical shape with curvature gradient generates a Laplace pressure gradient along the droplet, which is responsible for droplet motion. In this study, the triangular shape was used which also generates a Laplace pressure gradient along the droplet. A bioinspired surface, composed of a hydrophilic triangular pattern surrounded by a rim of superhydrophobic region, was used to transport water collected from the fog on the hydrophilic pattern. The growing droplets start to coalesce into bigger ones. Eventually, they are big enough to touch the superhydrophobic borders, which trigger the transport motion. Droplet mobility and water collection measurements were made on triangular patterns with various geometries to determine the most efficient configurations. Results from this study can be used to enhance the performance of water collection systems from fog. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

scholarly journals A Simple Conservation Tool to Aid Restoration of Amphibians following High-Severity Wildfires: Use of PVC Pipes by Green Tree Frogs (Hyla cinerea) in Central Texas, USA

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 649
Author(s):  
Thanchira Suriyamongkol ◽  
Kaitlyn Forks ◽  
Andrea Villamizar-Gomez ◽  
Hsiao-Hsuan Wang ◽  
William E. Grant ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Large Diameter ◽  
Small Diameter ◽  
Iucn Red List ◽  
Tree Frog ◽  
Hyla Cinerea ◽  
High Severity ◽  
Central Texas ◽  
Tree Frogs ◽  
Pipe Size

Amphibians are the most threatened vertebrate class based on the IUCN Red List. Their decline has been linked to anthropogenic activities, with wildfires being among the most conspicuous agents of habitat alterations affecting native amphibians. In 2011, the most destructive wildfire in Texas history occurred in the Lost Pines ecoregion of central Texas, USA, burning 39% of the 34,400 ha forest and drastically decreasing available habitats for many native wildlife species, including the green tree frog (Hyla cinerea). We investigated use of PVC pipes as artificial refuges for green tree frogs in different habitats within this post-fire pine forest. We monitored green tree frog use of small (diameter 38.1-mm, 1.5 inch) and large (diameter 50.8-mm, 2 inch) pipes located adjacent to, and 5 m from, ponds in burned and unburned areas over a 5-month period. We caught 227 frogs, 101 (24 adults and 77 juveniles) in burned and 126 (61 adults, 63 juveniles, and 2 unknown) in unburned areas. A relationship between pipe use by adults and/or juveniles and pipe location in burned versus unburned areas was found, but pipe use by adults and/or juveniles and pipe size were independent. Pipe use by adults and/or juveniles and pipe size were also independent. Juveniles were more frequently observed in pipes located adjacent to ponds. Our results confirmed that PVC pipes merit consideration as a simple, inexpensive, conservation tool to aid in restoration of green tree frog populations after high-severity wildfires. Such artificial refuges may be particularly important for survival of juveniles in severely altered post-fire habitats.

scholarly journals A new species of casque-headed tree frog, genus Aparasphenodon Miranda-Ribeiro (Amphibia: Anura: Hylidae), from the Atlantic Rainforest of southern Bahia, Brazil

Zootaxa ◽  
2009 ◽  
Vol 2123 (1) ◽  
pp. 46-54 ◽  
Author(s):  
BRUNO V. S. PIMENTA ◽  
MARCELO F. NAPOLI ◽  
CÉLIO F. B. HADDAD
Keyword(s):  
New Species ◽  
Atlantic Forest ◽  
Northeastern Brazil ◽  
Atlantic Rainforest ◽  
Tree Frog ◽  
Southern Bahia ◽  
Tree Frogs ◽  
A New Species ◽  
Forest Biome

A new species of Aparasphenodon is described from patches of arboreal restinga within the Atlantic Forest Biome, in a region known as Baixo Sul in southern Bahia, northeastern Brazil. Aparasphenodon arapapa sp. nov. is promptly diagnosed from other Aparasphenodon mainly by having small size (male snout-vent length 57.4–58.1 mm), loreal region flattened and wide, and canthus rostralis rounded and poorly elevated. The wide and flattened snout resembles that found in Triprion and Diaglena, and possibly is a parallelism (homoplasy) related to the phragmotic behavior of casque-headed tree frogs to their microhabitat usage. The decision to allocate the new species in the genus Aparasphenodon is discussed in detail, as the single morphological synapomorphy of the genus, the presence of a prenasal bone, is insufficient to morphologically relate the new species to Aparasphenodon, Triprion, or Diaglena.

scholarly journals Flexibility of network materials and the Rigid Unit Mode model: a personal perspective

2019 ◽  
Vol 377 (2149) ◽  
pp. 20180222 ◽  
Author(s):  
Martin T. Dove
Keyword(s):  
Phase Transitions ◽  
Science And Technology ◽  
Personal Perspective ◽  
Network Structures ◽  
Theme Issue ◽  
Natural And Synthetic

The Rigid Unit Mode model was initially developed to understand the origin of displacive phase transitions in network silicate structures. Here, we review the successes of the model, and consider how it might apply to a wider range of network structures. This article is part of the theme issue ‘Mineralomimesis: natural and synthetic frameworks in science and technology’.

scholarly journals Life Cycle of Tree Frogs (Hyla savygnyi) in Semi-Arid Habitats in Northern Israel

2015 ◽  
Vol 8 (1) ◽  
pp. 17 ◽  
Author(s):  
Gad Degani
Keyword(s):  
Life Cycle ◽  
Plasma Osmolality ◽  
Annual Rainfall ◽  
Tree Frog ◽  
Flowing Water ◽  
Breeding Sites ◽  
Hula Valley ◽  
Terrestrial Life ◽  
Tree Frogs ◽  
Semi Arid

The life cycle of tree frogs (Hyla savygnyi) in localities of various habitats in northern Israel in the Upper Galilee and Golan Heights (annual rainfall range of 500-1,000 mm) and the Hula Valley, ranging from 212 to 740 m above sea level (ASL), was studied. Tree frogs were observed around winter rain pools, springs and streams. Fifty-one different breeding places were monitored. Only ponds and springs having stable non-flowing water are used by tree frogs for reproduction and are where larvae can metamorphose. The male call in the breeding places attracts the female, who then comes to the male, and breeding occurs underwater. Breeding time in Israel varies according to location and geographical and ecological conditions. It takes place in March-April in northern Israel, the Upper Galilee, the Golan Heights and the Hula Valley. In various breeding places, larvae grow between April and June. Apparently tree frog larvae adapt to breeding places where stable water is found, such as in ponds or springs, but not to breeding places with flowing water such as streams or rivers. Various Anuran and Urodela larvae were found in the same breeding sites where the larvae of H. savygnyi were found, including Pseudepidalea Viridis, Rana bedriagae, Pelobates syriacus, Salamandra infraimmaculata and Triturs vittatus. Following metamorphosis, H. savygnyi adapt to terrestrial life in semi-arid habitats, and is found on plants or in hiding places under rocks and in holes to prevent dehydration particularly during hot and dry weather. The ability to change color helped the frogs to hide in various substrates. The rate of water loss of terrestrial H. savygnyi during dehydration is around 50% of body weight. Plasma osmolality increased from 200 mOsm/kg to about 450 mOsm/kg, which helped the tree frog to survive in semi-arid habitats.

scholarly journals Lessons from nature for green science and technology: an overview and bioinspired superliquiphobic/philic surfaces

2018 ◽  
Vol 377 (2138) ◽  
pp. 20180274 ◽  
Author(s):  
Bharat Bhushan
Keyword(s):  
Human Impact ◽  
Science And Technology ◽  
Theme Issue ◽  
Biologically Inspired ◽  
Aquatic Animals ◽  
Structured Surfaces ◽  
Commercial Interest ◽  
General Field ◽  
Commercial Applications

Nature has developed materials, objects and processes that function from the macroscale to the nanoscale. The emerging field of biomimetics allows one to mimic biology or nature to develop nanomaterials, nanodevices and processes which provide desirable properties. The biologically inspired materials and structured surfaces are being explored for various commercial applications. These should have minimum human impact on the environment, leading to eco-friendly or green science and technology. There are a large number of flora and fauna including bacteria, plants, land and aquatic animals, and seashells with properties of commercial interest. The paper presents an overview of the general field of biomimetics followed by a detailed overview of mechanisms, fabrication techniques and characterization of superliquiphobic/philic surfaces and their applications.This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.

Size Effect on Call Properties of Japanese Tree Frogs Revealed by Audio-Processing Technique

2017 ◽  
Vol 29 (1) ◽  
pp. 247-254 ◽  
Author(s):  
Ikkyu Aihara ◽  
◽  
Ryu Takeda ◽  
Takeshi Mizumoto ◽  
Takuma Otsuka ◽  
...  
Keyword(s):  
Breeding Site ◽  
Processing Technique ◽  
Calling Behavior ◽  
Tree Frog ◽  
Audio Processing ◽  
Core Function ◽  
Audio Data ◽  
Tree Frogs ◽  
Call Number ◽  
Positive Effect

[abstFig src='/00290001/23.jpg' width='300' text='Calling behavior of a male Japanese Tree Frog' ] Sensing the external environment is a core function of robots and autonomous mechanics. This function is useful for monitoring and analyzing the ecosystem for our deeper understanding of the nature and accomplishing the sustainable ecosystem. Here, we investigate calling behavior of male frogs by applying audio-processing technique on multiple audio data. In general, male frogs call from their breeding site, and a female frog approaches one of the males by hearing their calls. First, we conducted an indoor experiment to record spontaneous calling behavior of three male Japanese tree frogs, and then separated their call signals according to independent component analysis. The analysis of separated signals shows that chorus size (i.e., the number of calling frogs) has a positive effect on call number, inter-call intervals, and chorus duration. We speculate that a competition in a large chorus encourages the male frogs to make their call properties more attractive to conspecific females.

XXI. New observations upon the minute anatomy of the papillæ of the frog’s tongue

1864 ◽  
Vol 13 ◽  
pp. 384-386 ◽  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Caustic Soda ◽  
Tree Frog ◽  
Nerve Fibres ◽  
Fungiform Papillae ◽  
Hyla Arborea

After alluding to the observations of Axel Key, whose results accord with his own more closely than those of any other observer, the author refers particularly to the drawings of Hartmann, the latest writer upon the structure of the papillæ. According to the author, Dr. Hartmann, owing the defective method of preparation he employed, has failed to observe points which had been seen by others who had written before him, and which may now be most positively demonstrated. Hartmann’s process consisted in soaking the tissue for three days in solution of bichromate of potash, and afterwards adding solution of caustic soda. It can be shown by experiment that many structures which can be most clearly demonstrated by other modes of investigation, are rendered quite invisible by this process. Hartmann’s observations, like those of the author, have been made upon the papillæ of the tongue of the little green tree-frog ( Hyla arborea ). With reference to the termination of the nerves in the fungiform papillæ of the tongue of the Hyla, the author describes a plexus of very fine nerve-fibres, with nuclei, which has not been demonstrated before. Fibres resulting from the division of the dark-bordered fibres in the axis of the papilla can be traced directly into this plexus. From its upper part fine fibres, which interlace with one another in the most intricate manner, forming a layer which appears perfectly granular, except under a power of 1000 or higher, may be traced into the hemispheroidal mass of epitheium-like cells which surmounts the summit of the papilla. This hemi-spheroidal mass belongs not to epithelial, but to the nervous tissues. It adheres to the papilla after every epithelial cell has been removed; the so-called cells of which the entire mass consists cannot be separated from one another like epithelial cells; fibres exactly resembling nerve-fibres can often be seen between them; and very fine nerve-fibres may be traced into the mass from the bundle of nerves in the papilla.

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