Journal articles: 'Gecko'

1

Shang, Lei, Wen Bo Wang, Ting Ting Liu, Lei Cai, Hao Wang, and Zhen Dong Dai. "An Equipment Used for Studying the Vestibular Perception of Gekko gecko." Applied Mechanics and Materials 461 (November 2013): 570–76. http://dx.doi.org/10.4028/www.scientific.net/amm.461.570.

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The study of vestibule neurons specific firing mode of Gekko gecko under stimulus of different angles and rotating speeds has an important theoretical significance to reveal the control mechanism of Gekko geckos vestibular position as well as to the development of gecko-robots. A vari-angle rotating equipment was made to give different stimulus in study of Gekko geckos vestibular electrophysiology. The equipment mainly consisted of four parts as follows: fastening panel for stereotaxic instrument, shaft locking device, counterweight, driving system. The shaft locking device and counterweight realized tight fixation and torque equilibrium at different angles respectively. Fastening panel matched the general stereotaxic instrument. A stepper motor driver controlled the velocity and acceleration of rotation. Initial experiment verified that the equipment had superiority of easy operation, reliable positioning and accurate control of angle and speed, which indicated that it could meet the demand of the Gekko geckos vestibule research.

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BAUER, AARON M., MONTRI SUMONTHA, and OLIVIER S. G. PAUWELS. "A new red-eyed Gekko (Reptilia: Gekkonidae) from Kanchanaburi Province, Thailand." Zootaxa 1750, no. 1 (April 16, 2008): 32. http://dx.doi.org/10.11646/zootaxa.1750.1.3.

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A new species of gekkonid lizard, Gekko nutaphandi, is described from Kanchanaburi Province in central western Thailand. It is a member of the large-bodied Gekko gecko group and within this group is probably most closely related to G. siamensis Grossmann & Ulber, 1990 with which it shares a similar dorsal pattern of transverse series of white spots on a drab background. It differs from G. siamensis in its greater number of precloacal pores, lower number of dorsal tubercle rows, and in having red (versus green) eyes. Comparisons are also made with several other nominal Gekko species currently synonymized with G. gecko and with undescribed, but well-characterized “forms” of G. gecko. The new species is one of many recently described Southeast Asian geckos that appears to be restricted to limestone habitats and their surroundings.

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Peattie, Anne M., Carmel Majidi, Andrew Corder, and Robert J. Full. "Ancestrally high elastic modulus of gecko setal β-keratin." Journal of The Royal Society Interface 4, no. 17 (March 20, 2007): 1071–76. http://dx.doi.org/10.1098/rsif.2007.0226.

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Typical bulk adhesives are characterized by soft, tacky materials with elastic moduli well below 1 MPa. Geckos possess subdigital adhesives composed mostly of β-keratin, a relatively stiff material. Biological adhesives like those of geckos have inspired empirical and modelling research which predicts that even stiff materials can be effective adhesives if they take on a fibrillar form. The molecular structure of β-keratin is highly conserved across birds and reptiles, suggesting that material properties of gecko setae should be similar to that of β-keratin previously measured in birds, but this has yet to be established. We used a resonance technique to measure elastic bending modulus in two species of gecko from disparate habitats. We found no significant difference in elastic modulus between Gekko gecko (1.6 GPa±0.15 s.e.; n =24 setae) and Ptyodactylus hasselquistii (1.4 GPa±0.15 s.e.; n =24 setae). If the elastic modulus of setal keratin is conserved across species, it would suggest a design constraint that must be compensated for structurally, and possibly explain the remarkable variation in gecko adhesive morphology.

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Fakhri Fauzan, Muhammad, Quraisy Zakky, Ibnu Hibban Hartono, Awal Riyanto, and Amir Hamidy. "Habitat Preference and Population Study of House Gecko (Gekko gecko) in Seribu Islands, Special Capital Region of Jakarta." Jurnal Biologi Indonesia 18, no. 2 (2022): 205–12. http://dx.doi.org/10.47349/jbi/18022022/205.

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The house gecko (Gekko gecko) or tokek is a reptile species known widely used as an export commodity. Overexploitation can threaten wild populations of tokek in the wild. The research was conducted through a Visual Encounter Survey on the islands of Tidung, Pari, and Untung Jawa from 27 November to 02 December 2021. We also distributed questionnaires about the insight and presence of geckos in residents' homes or buildings. The number of respondents have been interviewed are 117 people, while for direct observation the results obtained are 273 individuals. The highest number of geckos was found on Pari Island and the least was on Untung Jawa Island. The house gecko is distributed throughout on these islands and is relatively more abundant in residential areas. The house gecko is most found on power poles and building walls and in breadfruit trees (Artocarpus altilis). Area of The Kepulauan Seribu is about 474562 hectares with a land area of 877 hectares. The population density of tokek based on direct observation was 13.60 individuals/ha. Therefore, the estimated population of tokek; in the Seribu Islands based on direct observations is around 11930.12 individuals.

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Reese, David J., JM Kinsella, Jacqueline M. Zdziarski, Qi-Yun Zeng, and Ellis C. Greiner. "Parasites in 30 Captive Tokay Geckos, Gekko gecko." Journal of Herpetological Medicine and Surgery 14, no. 2 (January 2004): 21–25. http://dx.doi.org/10.5818/1529-9651.14.2.21.

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Keating, Shannon E., Madison Blumer, L. Lee Grismer, Aung Lin, Stuart V. Nielsen, Myint Kyaw Thura, Perry L. Wood, Evan S. H. Quah, and Tony Gamble. "Sex Chromosome Turnover in Bent-Toed Geckos (Cyrtodactylus)." Genes 12, no. 1 (January 19, 2021): 116. http://dx.doi.org/10.3390/genes12010116.

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Lizards and snakes (squamates) are known for their varied sex determining systems, and gecko lizards are especially diverse, having evolved sex chromosomes independently multiple times. While sex chromosomes frequently turnover among gecko genera, intrageneric turnovers are known only from Gekko and Hemidactylus. Here, we used RADseq to identify sex-specific markers in two species of Burmese bent-toed geckos. We uncovered XX/XY sex chromosomes in Cyrtodactylus chaunghanakwaensis and ZZ/ZW sex chromosomes in Cyrtodactylus pharbaungensis. This is the third instance of intrageneric turnover of sex chromosomes in geckos. Additionally, Cyrtodactylus are closely related to another genus with intrageneric turnover, Hemidactylus. Together, these data suggest that sex chromosome turnover may be common in this clade, setting them apart as exceptionally diverse in a group already known for diverse sex determination systems.

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Stewart, William J., and Timothy E. Higham. "Passively stuck: death does not affect gecko adhesion strength." Biology Letters 10, no. 12 (December 2014): 20140701. http://dx.doi.org/10.1098/rsbl.2014.0701.

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Many geckos use adhesive toe pads on the bottom of their digits to attach to surfaces with remarkable strength. Although gecko adhesion has been studied for hundreds of years, gaps exist in our understanding at the whole-animal level. It remains unclear whether the strength and maintenance of adhesion are determined by the animal or are passively intrinsic to the system. Here we show, for the first time, that strong adhesion is produced passively at the whole-animal level. Experiments on both live and recently euthanized tokay geckos ( Gekko gecko ) revealed that death does not affect the dynamic adhesive force or motion of a gecko foot when pulled along a vertical surface. Using a novel device that applied repeatable and steady-increasing pulling forces to the foot in shear, we found that the adhesive force was similarly high and variable when the animal was alive (mean ± s.d. = 5.4 ± 1.7 N) and within 30 min after death (5.4 ± 2.1 N). However, kinematic analyses showed that live geckos are able to control the degree of toe pad engagement and can rapidly stop strong adhesion by hyperextending the toes. This study offers the first assessment of whole-animal adhesive force under extremely controlled conditions. Our findings reveal that dead geckos maintain the ability to adhere with the same force as living animals, disproving that strong adhesion requires active control.

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Hawkes, Elliot W., Eric V. Eason, David L. Christensen, and Mark R. Cutkosky. "Human climbing with efficiently scaled gecko-inspired dry adhesives." Journal of The Royal Society Interface 12, no. 102 (January 2015): 20140675. http://dx.doi.org/10.1098/rsif.2014.0675.

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Since the discovery of the mechanism of adhesion in geckos, many synthetic dry adhesives have been developed with desirable gecko-like properties such as reusability, directionality, self-cleaning ability, rough surface adhesion and high adhesive stress. However, fully exploiting these adhesives in practical applications at different length scales requires efficient scaling (i.e. with little loss in adhesion as area grows). Just as natural gecko adhesives have been used as a benchmark for synthetic materials, so can gecko adhesion systems provide a baseline for scaling efficiency. In the tokay gecko ( Gekko gecko ), a scaling power law has been reported relating the maximum shear stress σ max to the area A : σ max ∝ A −1/4 . We present a mechanical concept which improves upon the gecko's non-uniform load-sharing and results in a nearly even load distribution over multiple patches of gecko-inspired adhesive. We created a synthetic adhesion system incorporating this concept which shows efficient scaling across four orders of magnitude of area, yielding an improved scaling power law: σ max ∝ A −1/50 . Furthermore, we found that the synthetic adhesion system does not fail catastrophically when a simulated failure is induced on a portion of the adhesive. In a practical demonstration, the synthetic adhesion system enabled a 70 kg human to climb vertical glass with 140 cm 2 of adhesive per hand.

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BAUER, AARON M., ANTHONY P. RUSSELL, and ROBERT E. SHADWICK. "Mechanical Properties and Morphological Correlates of Fragile Skin in Gekkonid Lizards." Journal of Experimental Biology 145, no. 1 (September 1, 1989): 79–102. http://dx.doi.org/10.1242/jeb.145.1.79.

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The mechanical properties of gekkonid lizard skin are investigated for the first time. Although the skin of certain geckos, such as Gekko gecko, behaves in ‘typical’ vertebrate fashion, that of others, such as Ailuronyx seychellensis, exhibits unusual properties associated with identifiable morphological specializations. Light and scanning electron microscopy reveal that Ailuronyx dermis is functionally bilayered; the stratum compactum is divided into inner and outer layers by intervening loose connective tissue. The inner layer is strong and tough and does not differ significantly in its properties from that of Gekko gecko whole skin. The much thicker outer layer, however, is only 1/20 as strong and 1/50 as tough as the inner layer, and exhibits preformed zones of weakness. In nature, Ailuronyx parts with considerable portions of the outer components of the skin as an antipredator escape mechanism. Skin samples from 17 additional gecko species varied considerably in their strength, stiffness and toughness. None of the forms with tough skin employs regional integumentary loss as a predator escape strategy. Weak skin alone is not sufficient to permit regional integumentary loss, as the capability to lose the skin involves not only inherent properties of the tissue, but also features of the mechanical interaction of skin layers with one another and with the underlying body wall.

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Gogoi, Manoj, Sumanta Kundu, Jadumoni Goswami, Dibyajyoti Saikia, and Naveen Pandey. "First record of tail bifurcation in Tokey Gecko (Gekko gecko) from the Kaziranga, Assam, India : a field observation." INTERNATIONAL JOURNAL OF EXPERIMENTAL RESEARCH AND REVIEW 15 (April 30, 2018): 5–8. http://dx.doi.org/10.52756/ijerr.2018.v15.002.

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The Tokay Gecko (Gekko gecko) is the second largest surviving Gecko species and are distributed across much of South-East Asia, Southern China and Northeastern India and Nepal. In Kaziranga landscape Tokay Gecko are fairly common and frequently seen around households in rural area. Though tail bifurcation is common in lizards but till date no recorded specimen of Tokey Gecko with bifurcated tail had been reported from Kaziranga Landscape.

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Suwatik, Suwatik, Nenden Sri Wahyuni, Santi Mulyawati, Mulik Siti Nur Rohmah, Rr Indira Dewi Anggraeni, Raflen Ari Gerungan, and Diki Diki. "Preliminary Study of Common House Gecko (Cosymbotus platyurus) Density in Java Island." International Journal of Research in Community Services 2, no. 4 (October 5, 2021): 142–49. http://dx.doi.org/10.46336/ijrcs.v2i4.226.

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Common house gecko (Cosymbotus platyurus) is the most abundant house gecko species in Indonesia. The geckos live in home yard, garden, and in homes. It is part of food chain in its habitat, as its preys include cockroaches, flies, and termites. Previous studies found that this gecko are not found in mountainous area in West Java. In this study, the researchers observe population density of common house geckos in various types of habitats (houses and parks) with their home territory. The methods used were direct survey methods followed by literature study. The study is conducted in Java island (Jakarta, Tangerang, Bandung, Bogor, Sleman). Preliminary result of this study is house geckos are very active at night, because of the effect of light produced by lights that attract the attention of insects, gecko food.

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Stark, Alyssa Y., and Christopher T. Mitchell. "Stick or Slip: Adhesive Performance of Geckos and Gecko-Inspired Synthetics in Wet Environments." Integrative and Comparative Biology 59, no. 1 (April 27, 2019): 214–26. http://dx.doi.org/10.1093/icb/icz008.

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Abstract The gecko adhesive system has inspired hundreds of synthetic mimics principally focused on replicating the strong, reversible, and versatile properties of the natural system. For geckos native to the tropics, versatility includes the need to remain attached to substrates that become wet from high humidity and frequent rain. Paradoxically, van der Waals forces, the principal mechanism responsible for gecko adhesion, reduce to zero when two contacting surfaces separate even slightly by entrapped water layers. A series of laboratory studies show that instead of slipping, geckos maintain and even improve their adhesive performance in many wet conditions (i.e., on wet hydrophobic substrates, on humid substrates held at low temperatures). The mechanism for this is not fully clarified, and likely ranges in scale from the chemical and material properties of the gecko’s contact structures called setae (e.g., setae soften and change surface confirmation when exposed to water), to their locomotor biomechanics and decision-making behavior when encountering water on a substrate in their natural environment (e.g., some geckos tend to run faster and stop more frequently on misted substrates than dry). Current work has also focused on applying results from the natural system to gecko-inspired synthetic adhesives, improving their performance in wet conditions. Gecko-inspired synthetic adhesives have also provided a unique opportunity to test hypotheses about the natural system in semi-natural conditions replicated in the laboratory. Despite many detailed studies focused on the role of water and humidity on gecko and gecko-inspired synthetic adhesion, there remains several outstanding questions: (1) what, if any, role does capillary or capillary-like adhesion play on overall adhesive performance of geckos and gecko-inspired synthetics, (2) how do chemical and material changes at the surface and in the bulk of gecko setae and synthetic fibrils change when exposed to water, and what does this mean for adhesive performance, and (3) how much water do geckos encounter in their native environment, and what is their corresponding behavioral response? This review will detail what we know about gecko adhesion in wet environments, and outline the necessary next steps in biological and synthetic system investigations.

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Uetz, Peter, Alex Slavenko, Shai Meiri, and Matthew Heinicke. "Gecko diversity: a history of global discovery." Israel Journal of Ecology and Evolution 66, no. 3-4 (November 6, 2020): 117–25. http://dx.doi.org/10.1163/22244662-bja10003.

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1935 gecko species (and 224 subspecies) were known in December 2019 in seven families and 124 genera. These nearly 2000 species were described by ~950 individuals of whom more than 100 described more than 10 gecko species each. Most gecko species were discovered during the past 40 years. The primary type specimens of all currently recognized geckos (including subspecies) are distributed over 161 collections worldwide, with 20 collections having about two thirds of all primary types. The primary type specimens of about 40 gecko taxa have been lost or unknown. The phylogeny of geckos is well studied, with DNA sequences being available for ~76% of all geckos (compared to ~63% in other reptiles) and morphological characters now being collected in databases. Geographically, geckos occur on five continents and many islands but are most species-rich in Australasia (which also houses the greatest diversity of family-level taxa), Southeast Asia, Africa, Madagascar, and the West Indies. Among countries, Australia has the highest number of geckos (241 species), with India, Madagascar, and Malaysia being the only other countries with more than 100 described species each. As expected, when correcting for land area, countries outside the tropics have fewer geckos.

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Villalobos-Juárez, Ivan, Elí García-Padilla, José Jesús Sigala-Rodríguez, and Giovanna Villalobos-Jiménez. "First records of the Tokay Gecko, Gekko gecko (Linnaeus, 1758) (Squamata, Gekkonidae), in Mexico." Check List 18, no. 5 (September 13, 2022): 957–60. http://dx.doi.org/10.15560/18.5.957.

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Wang, Xiaoqing, Wenbo Wang, and Zhendong Dai. "The Neural Control Mechanisms of Gekkonid Adhesion Locomotion: The Effect of Spinal Cord Lesions." Biomimetics 7, no. 3 (July 22, 2022): 98. http://dx.doi.org/10.3390/biomimetics7030098.

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Objective: the role of the supraspinal system in the neural control mechanisms of adhesion locomotor pattern formation was studied in lizard Gekko gecko. Methods: the locomotor performance and adaptation of the chronically lesioned Gekko gecko was documented before and after either partial or complete spinal lesions. They were filmed moving on a flat and smooth platform that was inclined at 0°, ±45°, and ±90°, as well as the horizontal mats and the vertical oak background board in the terraria, to evaluate locomotor functional recovery. The geckos were also tested on the platform by two half and nose-up or -down rotations in steps of 15° throughout 180° to investigate the recovery of the ability to respond dynamically to external perturbations. Results: after relatively small lesions of a hemisection, the locomotor performance was largely indistinguishable from that before and after a sham operation. During the initial period of recovery after the largest lesions of a dorsal or a ventral hemisection within 1 wk, the geckos behaved essentially as the complete spinal geckos, while permanent deficits in locomotor performance remained and did not decrease afterwards for ≥6 mth. Conclusions: by analyzing the correlation among locomotor performances, and between locomotor performances and spinal cord lesions, we suggest that the dorsal spinal pathways and ventral spinal pathways participate, respectively, in the control of the limb coupling, and in the deployment and the detachment of the adhesive apparatus. The present study will provide certain neurobiological guidance for the design of bio-robots, as well as sprawling robots inspired by the geckos.

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Atmaja, Vesti Yunisya, Deni Parlindungan, Sipriyadi Sipriyadi, Fery Fernando Sinaga, Ika Saputri, Reti Novianti, Untung Priadi, and Widia Gusti. "Population Estimation of Double–Spotted Gecko, Gekko monarchus (Sclegel, 1836) at 5 Regency in Bengkulu Province." JURNAL PEMBELAJARAN DAN BIOLOGI NUKLEUS 8, no. 3 (November 25, 2022): 593–607. http://dx.doi.org/10.36987/jpbn.v8i3.3242.

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The Double–Spotted Gecko (Gekko monarchus) is one of the reptiles on the list of wild animals given an annual utilization quota for their capture in the wild. Bengkulu Province, as one of the distribution place of G. monarchus does not yet have data on its population. The research was conducted on 13 November to 2 December 2021, using two methods: interviews with the community and a Visual Encountered Survey at night. The research area in the five districts is 61.49 ha, the number of houses visited is 433, and the number of people interviewed is 386. The number of geckos counted in the interviews was 315, while from direct observation, there were 275. Geckos were most found at house and dominated (41.2%) by hiding between wooden walls. Based on the results of extrapolation calculations, the population estimates for the Double–Spotted Gecko are North Bengkulu 43,720–54,427 individuals; Mukomuko 32,997–51,810 tails; Central Bengkulu 6,248–9,187 individuals; Total 39,883–72,720 individuals; and South Bengkulu 11,469–11,592 individuals.

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Hsu, Ping Yuan, Liehui Ge, Xiaopeng Li, Alyssa Y. Stark, Chrys Wesdemiotis, Peter H. Niewiarowski, and Ali Dhinojwala. "Direct evidence of phospholipids in gecko footprints and spatula–substrate contact interface detected using surface-sensitive spectroscopy." Journal of The Royal Society Interface 9, no. 69 (August 24, 2011): 657–64. http://dx.doi.org/10.1098/rsif.2011.0370.

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Observers ranging from Aristotle to young children have long marvelled at the ability of geckos to cling to walls and ceilings. Detailed studies have revealed that geckos are ‘sticky’ without the use of glue or suction devices. Instead, a gecko's stickiness derives from van der Waals interactions between proteinaceous hairs called setae and substrate. Here, we present surprising evidence that although geckos do not use glue, a residue is transferred on surfaces as they walk—geckos leave footprints . Using matrix-free nano-assisted laser desorption-ionization mass spectrometry, we identified the residue as phospholipids with phosphocholine head groups. Moreover, interface-sensitive sum-frequency generation spectroscopy revealed predominantly hydrophobic methyl and methylene groups and the complete absence of water at the contact interface between a gecko toe pad and the substrate. The presence of lipids has never been considered in current models of gecko adhesion. Our analysis of gecko footprints and the toe pad–substrate interface has significant consequences for models of gecko adhesion and by extension, the design of synthetic mimics.

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Go, Seokmin, Seonmi Kang, Jun Kwon, Sechang Park, and Kangmoon Seo. "Optical coherence tomography of the Tokay gecko ( Gekko gecko ) eye." Veterinary Ophthalmology 23, no. 5 (August 2, 2020): 863–71. http://dx.doi.org/10.1111/vop.12810.

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Niewiarowski, Peter H., Ali Dhinojwala, and Austin M. Garner. "A Physical Model Approach to Gecko Adhesion Opportunity and Constraint: How Rough Could It Be?" Integrative and Comparative Biology 59, no. 1 (May 7, 2019): 203–13. http://dx.doi.org/10.1093/icb/icz029.

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AbstractIt has been nearly 20 years since Autumn and colleagues established the central role of van der Waals intermolecular forces in how geckos stick. Much has been discovered about the structure and function of fibrillar adhesives in geckos and other taxa, and substantial success has been achieved in translating natural models into bioinspired synthetic adhesives. Nevertheless, synthetics still cannot match the multidimensional performance observed in the natural gecko system that is simultaneously robust to dirt and water, resilient over thousands of cycles, and purportedly competent on surfaces that are rough at drastically different length scales. Apparent insensitivity of adhesion to variability in roughness is particularly interesting from both a theoretical and applied perspective. Progress on understanding the extent to which and the basis of how the gecko adhesive system is robust to variation in roughness is impeded by the complexity of quantifying roughness of natural surfaces and a dearth of data on free-ranging gecko substrate use. Here we review the main challenges in characterizing rough surfaces as they relate to collecting relevant estimates of variation in gecko adhesive performance across different substrates in their natural habitats. In response to these challenges, we propose a practical protocol (borrowing from thermal biophysical ecological methods) that will enable researchers to design detailed studies of structure–function relationships of the gecko fibrillar system. Employing such an approach will help provide specific hypotheses about how adhesive pad structure translates into a capacity for robust gecko adhesion across large variation in substrate roughness. Preliminary data we present on this approach suggest its promise in advancing the study of how geckos deal with roughness variation. We argue and outline how such data can help advance development of design parameters to improve bioinspired adhesives based on the gecko fibrillar system.

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Sander, Samantha J., Robert J. Ossiboff, Tracy Stokol, James C. Steeil, and Donald L. Neiffer. "Endolymphatic Sac Carcinoma In Situ in a Tokay Gecko (Gekko gecko)." Journal of Herpetological Medicine and Surgery 25, no. 3-4 (December 1, 2015): 82. http://dx.doi.org/10.5818/1529-9651-25.3.82.

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Izadi, Hadi, Katherine M. E. Stewart, and Alexander Penlidis. "Role of contact electrification and electrostatic interactions in gecko adhesion." Journal of The Royal Society Interface 11, no. 98 (September 6, 2014): 20140371. http://dx.doi.org/10.1098/rsif.2014.0371.

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Geckos, which are capable of walking on walls and hanging from ceilings with the help of micro-/nano-scale hierarchical fibrils (setae) on their toe pads, have become the main prototype in the design and fabrication of fibrillar dry adhesives. As the unique fibrillar feature of the toe pads of geckos allows them to develop an intimate contact with the substrate the animal is walking on or clinging to, it is expected that the toe setae exchange significant numbers of electric charges with the contacted substrate via the contact electrification (CE) phenomenon. Even so, the possibility of the occurrence of CE and the contribution of the resulting electrostatic interactions to the dry adhesion of geckos have been overlooked for several decades. In this study, by measuring the magnitude of the electric charges, together with the adhesion forces, that gecko foot pads develop in contact with different materials, we have clarified for the first time that CE does contribute effectively to gecko adhesion. More importantly, we have demonstrated that it is the CE-driven electrostatic interactions which dictate the strength of gecko adhesion, and not the van der Waals or capillary forces which are conventionally considered as the main source of gecko adhesion.

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Arredondo, Cristóbal, and Herman Núñez. "Tarentola mauritanica (Linnaeus, 1758), a New Species of Lizard for Chile (Reptilia, Phyllodactylidae)." Boletín Museo Nacional de Historia Natural 63 (December 28, 2014): 73–76. http://dx.doi.org/10.54830/bmnhn.v63.2014.105.

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Tarentola mauritanica, salamanquesa común and Geco mediterráneo (in Spanish), Moorish Wall Gecko and Moorish Gecko (in English), is a widespread gecko around the Mediterranean African and European zones (Joger 1984; see also http://maps.iucnredlist.org/map.html?id=61578), including Greece and Crete (ibid.). The last source describes introduced populations in the north of Italy, Balearic Islands, and Tenerife. The Moorish Wall Gecko is a species that exploits human resources to inhabit areas beyond its original Mediterranean distribution. Outside Europe and north Africa, it has been introduced and established in San Diego County in the U.S. (Mahrdt 1998; see more details in http://reptile-database.reptarium.cz/species?genus=Tarentola&species=mauritanica).

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Gamble, Tony. "Duplications in Corneous Beta Protein Genes and the Evolution of Gecko Adhesion." Integrative and Comparative Biology 59, no. 1 (April 27, 2019): 193–202. http://dx.doi.org/10.1093/icb/icz010.

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Abstract Corneous proteins are an important component of the tetrapod integument. Duplication and diversification of keratins and associated proteins are linked with the origin of most novel integumentary structures like mammalian hair, avian feathers, and scutes covering turtle shells. Accordingly, the loss of integumentary structures often coincides with the loss of genes encoding keratin and associated proteins. For example, many hair keratins in dolphins and whales have become pseudogenes. The adhesive setae of geckos and anoles are composed of both intermediate filament keratins (IF-keratins, formerly known as alpha-keratins) and corneous beta-proteins (CBPs, formerly known as beta-keratins) and recent whole genome assemblies of two gecko species and an anole uncovered duplications in seta-specific CBPs in each of these lineages. While anoles evolved adhesive toepads just once, there are two competing hypotheses about the origin(s) of digital adhesion in geckos involving either a single origin or multiple origins. Using data from three published gecko genomes, I examine CBP gene evolution in geckos and find support for a hypothesis where CBP gene duplications are associated with the repeated evolution of digital adhesion. Although these results are preliminary, I discuss how additional gecko genome assemblies, combined with phylogenies of keratin and associated protein genes and gene duplication models, can provide rigorous tests of several hypotheses related to gecko CBP evolution. This includes a taxon sampling strategy for sequencing and assembly of gecko genomes that could help resolve competing hypotheses surrounding the origin(s) of digital adhesion.

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Gumbs, Rikki, Rachel C. Williams, Anthony M. Lowney, and Darrell Smith. "Spatial and species-level metrics reveal global patterns of irreplaceable and imperiled gecko phylogenetic diversity." Israel Journal of Ecology and Evolution 66, no. 3-4 (November 6, 2020): 239–52. http://dx.doi.org/10.1163/22244662-bja10020.

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Abstract Phylogenetic Diversity (PD) is increasingly recognised as a useful tool for prioritising species and regions for conservation effort. Increased availability of spatial and phylogenetic data for reptiles now facilitates their inclusion in phylogenetically-informed conservation prioritisation efforts. Geckos are a highly divergent and diverse clade that comprises almost 20% of global reptile diversity. Their global distribution is coincident with numerous anthropogenic threats, making them worthy of conservation prioritisation. Here, we combine phylogenetic, spatial distribution and extinction risk data for geckos with global human encroachment data to identify both regions and species representing irreplaceable gecko diversity at risk from human pressure. We show that high levels of irreplaceable gecko diversity are restricted to regions under intense human pressure, such as India, Sri Lanka and the Caribbean. There is a lack of extinction risk data for the western regions of Angola and Namibia, and yet these regions harbour high levels of irreplaceable diversity. At the species level, geckos display more unique PD than other lizards and snakes and are of greater conservation concern under our metric. The PD represented by Data Deficient geckos is at comparable risk to that of Endangered species. Finally, estimates of potential gecko diversity loss increase by up to 300% when species lacking extinction risk data are included. Our analyses show that many evolutionarily unique gecko species are poorly known and are at an increased risk of extinction. Targeted research is needed to elucidate the conservation status of these species and identify conservation priorities.

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Gu, Hai-Feng, Yun Xia, Rui Peng, Bang-Hui Mo, Li Li, and Xiao-Mao Zeng. "Authentication of Chinese Crude Drug Gecko by DNA Barcoding." Natural Product Communications 6, no. 1 (January 2011): 1934578X1100600. http://dx.doi.org/10.1177/1934578x1100600117.

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Gekko gecko, an animal used as a valued traditional Chinese medicine, has been widely used for over 2000 years. Due to localized habitat destruction, the amount of G. gecko has dramatically decreased in recent years. As a result, more and more adulterants have been detected in the traditional medicine, which has resulted in a chaotic market. Therefore, a correct identification method is badly needed. In this study, we employed a new molecular method of DNA barcoding for discriminating gecko from its adulterants. Fifty-seven specimens of gecko and its adulterants were collected as test samples. The full-barcode and mini-barcode sequences of these specimens were separately amplified and sequenced separately. Together with other published barcode sequences, we detected that the intra-specific sequence diversity was far lower than the inter-specific diversity in G. gecko and its adulterants (3% compared with 35% in full-length barcode; 4% compared with 33.5% in mini-barcode). These results showed that both the full-length and mini-barcodes were effective for identifying gecko, which suggested that the DNA barcode could be an effective and powerful tool for identifying the Chinese crude drug gecko.

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Autumn, Kellar, and Nick Gravish. "Gecko adhesion: evolutionary nanotechnology." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 366, no. 1870 (January 11, 2008): 1575–90. http://dx.doi.org/10.1098/rsta.2007.2173.

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If geckos had not evolved, it is possible that humans would never have invented adhesive nanostructures. Geckos use millions of adhesive setae on their toes to climb vertical surfaces at speeds of over 1 m s −1 . Climbing presents a significant challenge for an adhesive in requiring both strong attachment and easy rapid removal. Conventional pressure-sensitive adhesives (PSAs) are either strong and difficult to remove (e.g. duct tape) or weak and easy to remove (e.g. sticky notes). The gecko adhesive differs dramatically from conventional adhesives. Conventional PSAs are soft viscoelastic polymers that degrade, foul, self-adhere and attach accidentally to inappropriate surfaces. In contrast, gecko toes bear angled arrays of branched, hair-like setae formed from stiff, hydrophobic keratin that act as a bed of angled springs with similar effective elastic modulus to that of PSAs. Setae are self-cleaning and maintain function for months during repeated use in dirty conditions. Setae are an anisotropic ‘frictional adhesive’ in that adhesion requires maintenance of a proximally directed shear load, enabling either a tough bond or spontaneous detachment. Gecko-like synthetic adhesives may become the glue of the future—and perhaps the screw of the future as well.

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Shao, Donghao, Zhouyi Wang, Aihong Ji, Zhendong Dai, and Poramate Manoonpong. "A gecko-inspired robot with CPG-based neural control for locomotion and body height adaptation." Bioinspiration & Biomimetics 17, no. 3 (April 18, 2022): 036008. http://dx.doi.org/10.1088/1748-3190/ac5a3c.

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Abstract Today’s gecko-inspired robots have shown the ability of omnidirectional climbing on slopes with a low centre of mass. However, such an ability cannot efficiently cope with bumpy terrains or terrains with obstacles. In this study, we developed a gecko-inspired robot (Nyxbot) with an adaptable body height to overcome this limitation. Based on an analysis of the skeletal system and kinematics of real geckos, the adhesive mechanism and leg structure design of the robot were designed to endow it with adhesion and adjustable body height capabilities. Neural control with exteroceptive sensory feedback is utilised to realise body height adaptability while climbing on a slope. The locomotion performance and body adaptability of the robot were tested by conducting slope climbing and obstacle crossing experiments. The gecko robot can climb a 30° slope with spontaneous obstacle crossing (maximum obstacle height of 38% of the body height) and can climb even steeper slopes (up to 60°) without an obstacle or bump. Using 3D force measuring platforms for ground reaction force analysis of geckos and the robot, we show that the motions of the developed robot driven by neural control and the motions of geckos are dynamically comparable. To this end, this study provides a basis for developing climbing robots with adaptive bump/obstacle crossing on slopes towards more agile and versatile gecko-like locomotion.

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Aowphol, Anchalee, Kumthorn Thirakhupt, Jarujin Nabhitabhata, and Harold K. Voris. "Foraging ecology of the Tokay gecko, Gekko gecko in a residential area in Thailand." Amphibia-Reptilia 27, no. 4 (2006): 491–503. http://dx.doi.org/10.1163/156853806778877121.

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Abstract The foraging behavior of Gekko gecko was observed at the visitor complex of the Khao Khiao Open Zoo at the Khao Khiao-Khao Chomphu Wildlife Sanctuary in Chon Buri Province, Thailand. Foraging parameters of G. gecko (foraging period, time spent moving, foraging attempts, foraging success, prey size consumed, and foraging distance) did not vary significantly between males, females, and juveniles. Individuals foraged between 18:01 and 09:00 hrs. Peak emergence time was between 18:01 and 20:00 hrs. Peak retreat time was between 04:01 and 07:00 hrs. Major food items included insects of the orders Lepidoptera, Orthoptera, and Coleoptera. Prey sizes of males, females, and juveniles were not significantly different, indicating no prey size selection. This may have been due to low insect availability in the habitat. Gekko gecko tended to be a sit-and-wait forager spending most of the time waiting for active prey. However, it sometimes foraged more actively when insect abundance was relatively high. Foraging behavior of males tended to be more variable than females and juveniles. In addition, variation in foraging parameters among individuals was noted. Foraging strategies of G. gecko observed in this study are interpreted in the context of optimal foraging theory.

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Russell, Anthony P., Alyssa Y. Stark, and Timothy E. Higham. "The Integrative Biology of Gecko Adhesion: Historical Review, Current Understanding, and Grand Challenges." Integrative and Comparative Biology 59, no. 1 (May 7, 2019): 101–16. http://dx.doi.org/10.1093/icb/icz032.

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Abstract Geckos are remarkable in their ability to reversibly adhere to smooth vertical, and even inverted surfaces. However, unraveling the precise mechanisms by which geckos do this has been a long process, involving various approaches over the last two centuries. Our understanding of the principles by which gecko adhesion operates has advanced rapidly over the past 20 years and, with this knowledge, material scientists have attempted to mimic the system to create artificial adhesives. From a biological perspective, recent studies have examined the diversity in morphology, performance, and real-world use of the adhesive apparatus. However, the lack of multidisciplinarity is likely a key roadblock to gaining new insights. Our goals in this paper are to 1) present a historical review of gecko adhesion research, 2) discuss the mechanisms and morphology of the adhesive apparatus, 3) discuss the origin and performance of the system in real-world contexts, 4) discuss advancement in bio-inspired design, and 5) present grand challenges in gecko adhesion research. To continue to improve our understanding, and to more effectively employ the principles of gecko adhesion for human applications, greater intensity and scope of interdisciplinary research are necessary.

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Ivlev, Yu F., A. I. Il’in, and O. V. Trofimov. "Viscoelastic features of adhesive setae of the tokay gecko (Gekko gecko L.)." Doklady Biological Sciences 467, no. 1 (March 2016): 82–85. http://dx.doi.org/10.1134/s0012496616020101.

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Micinilio, Jim. "Ivermectin for the Treatment of Pentastomids in a Tokay Gecko, Gekko gecko." Bulletin of the Association of Reptilian and Amphibian Veterinarians 6, no. 2 (January 1996): 5–6. http://dx.doi.org/10.5818/1076-3139.6.2.5.

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Manley, Geoffrey A., Lothar Gallo, and Christine Köppl. "Spontaneous otoacoustic emissions in two gecko species, Gekko gecko and Eublepharis macularius." Journal of the Acoustical Society of America 99, no. 3 (March 1996): 1588–603. http://dx.doi.org/10.1121/1.414680.

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Hu, Shihao, Stephanie Lopez, Peter H. Niewiarowski, and Zhenhai Xia. "Dynamic self-cleaning in gecko setae via digital hyperextension." Journal of The Royal Society Interface 9, no. 76 (June 13, 2012): 2781–90. http://dx.doi.org/10.1098/rsif.2012.0108.

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Gecko toe pads show strong adhesion on various surfaces yet remain remarkably clean around everyday contaminants. An understanding of how geckos clean their toe pads while being in motion is essential for the elucidation of animal behaviours as well as the design of biomimetic devices with optimal performance. Here, we test the self-cleaning of geckos during locomotion. We provide, to our knowledge, the first evidence that geckos clean their feet through a unique dynamic self-cleaning mechanism via digital hyperextension. When walking naturally with hyperextension, geckos shed dirt from their toes twice as fast as they would if walking without hyperextension, returning their feet to nearly 80 per cent of their original stickiness in only four steps. Our dynamic model predicts that when setae suddenly release from the attached substrate, they generate enough inertial force to dislodge dirt particles from the attached spatulae. The predicted cleaning force on dirt particles significantly increases when the dynamic effect is included. The extraordinary design of gecko toe pads perfectly combines dynamic self-cleaning with repeated attachment/detachment, making gecko feet sticky yet clean. This work thus provides a new mechanism to be considered for biomimetic design of highly reuseable and reliable dry adhesives and devices.

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ARNOLD, E. NICHOLAS, and GEORGE POINAR. "A 100 million year old gecko with sophisticated adhesive toe pads, preserved in amber from Myanmar." Zootaxa 1847, no. 1 (August 11, 2008): 62. http://dx.doi.org/10.11646/zootaxa.1847.1.5.

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A new genus and species of gecko is described from a posterior lower limb and foot, and a partial tail, preserved in Lower Cretaceous amber from Myanmar that is 97–110My old. It appears to be the oldest unequivocal fossil gecko, predating fragmentary skeletal remains from the Upper Cretaceous and being 43–56 My older than Yanatarogecko from the Lower Eocene, previously the oldest known gecko preserved in amber. It also provides firm evidence that gekkotans and possibly gekkonids were in Asia at this time. The Myanmar specimen shows, that the distinctive foot proportions and sophisticated adhesive mechanism, involving pads on the toes with transverse lamellae probably bearing numerous hairlike setae found in many modern geckos, had already evolved around 100My ago. The specimen is very small, even compared with juveniles of the smallest living geckos. However, the high numbers of lamellae on its toe pads suggest it is from a juvenile of a species with relatively large adult body size.

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Gulimova, Victoria, Alexandra Proshchina, Anastasia Kharlamova, Yuliya Krivova, Valery Barabanov, Rustam Berdiev, Victor Asadchikov, Alexey Buzmakov, Denis Zolotov, and Sergey Saveliev. "Reptiles in Space Missions: Results and Perspectives." International Journal of Molecular Sciences 20, no. 12 (June 20, 2019): 3019. http://dx.doi.org/10.3390/ijms20123019.

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Reptiles are a rare model object for space research. However, some reptile species demonstrate effective adaptation to spaceflight conditions. The main scope of this review is a comparative analysis of reptile experimental exposure in weightlessness, demonstrating the advantages and shortcomings of this model. The description of the known reptile experiments using turtles and geckos in the space and parabolic flight experiments is provided. Behavior, skeletal bones (morphology, histology, and X-ray microtomography), internal organs, and the nervous system (morphology, histology, and immunohistochemistry) are studied in the spaceflight experiments to date, while molecular and physiological results are restricted. Therefore, the results are discussed in the scope of molecular data collected from mammalian (mainly rodents) specimens and cell cultures in the parabolic and orbital flights and simulated microgravity. The published data are compared with the results of the gecko model studies after the 12–44.5-day spaceflights with special reference to the unique peculiarities of the gecko model for the orbital experiments. The complex study of thick-toed geckos after three spaceflights, in which all geckos survived and demonstrated effective adaptation to spaceflight conditions, was performed. However, future investigations are needed to study molecular mechanisms of gecko adaptation in space.

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Packard, Mary J., and Karl F. Hirsch. "Structure of shells from eggs of the geckos Gekko gecko and Phelsuma madagascarensis." Canadian Journal of Zoology 67, no. 3 (March 1, 1989): 746–58. http://dx.doi.org/10.1139/z89-106.

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The geckos Gekko gecko and Phelsuma madagascarensis lay small, round eggs with brittle, inflexible shells. Eggshells of both species consist of a thick calcareous layer with an organic layer adhering to the outer surface and a thin, fibrous shell membrane attached to the inner surface. The calcareous layer consists of calcium carbonate in the form of calcite, and is organized into ill-defined columns that form a dense crystalline matrix. The inner face of columns (the aspect attached to the shell membrane) consists of crystallites of variable size and morphology. Eggshells contain a great deal of organic matter, and prolonged treatment with NaOH leaves the calcareous layer riddled with horizontal fissures reflecting the removal of organic matrix. Pores through the calcareous layer of eggshells of both species terminate at the outer surface in a variable number of small openings. The pore canal in G. gecko eggshells occurs as a series of labyrinthine channels in a calcareous concretion that fits loosely within a corresponding cleft in the calcareous layer. Detachment of the concretion leaves a shallow pit or depression on the inner surface of the eggshell. We observed concretions and pits in P. madagascarensis eggshells but were unable to characterize the nature of the pore canal in this species.

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Cobos, Anthony J., and Timothy E. Higham. "Growing up in a rough world: scaling of frictional adhesion and morphology of the Tokay gecko (Gekko gecko)." Beilstein Journal of Nanotechnology 13 (November 9, 2022): 1292–302. http://dx.doi.org/10.3762/bjnano.13.107.

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Many geckos have the remarkable ability to reversibly adhere to surfaces using a hierarchical system that includes both internal and external elements. The vast majority of studies have examined the performance of the adhesive system using adults and engineered materials and substrates (e.g., acrylic glass). Almost nothing is known about how the system changes with body size, nor how these changes would influence the ability to adhere to surfaces in nature. Using Tokay geckos (Gekko gecko), we examined the post-hatching scaling of morphology and frictional adhesive performance in animals ranging from 5 to 125 grams in body mass. We quantified setal density, setal length, and toepad area using SEM. This was then used to estimate the theoretical maximum adhesive force. We tested performance with 14 live geckos on eight surfaces ranging from extremely smooth (acrylic glass) to relatively rough (100-grit sandpaper). Surfaces were attached to a force transducer, and multiple trials were conducted for each individual. We found that setal length scaled with negatively allometry, but toepad area scaled with isometry. Setal density remained constant across the wide range in body size. The relationship between body mass and adhesive performance was generally similar across all surfaces, but rough surfaces had much lower values than smooth surfaces. The safety factor went down with body mass and with surface roughness, suggesting that smaller animals may be more likely to occupy rough substrates in their natural habitat.

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Wu, Xuan, Xiaojie Wang, Tao Mei, and Shaoming Sun. "Mechanical analyses on the digital behaviour of the Tokay gecko ( Gekko gecko ) based on a multi-level directional adhesion model." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2179 (July 2015): 20150085. http://dx.doi.org/10.1098/rspa.2015.0085.

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This paper proposes a multi-level hierarchical model for the Tokay gecko ( Gekko gecko ) adhesive system and analyses the digital behaviour of the G. gecko under macro/meso-level scale. The model describes the structures of G. gecko 's adhesive system from the nano-level spatulae to the sub-millimetre-level lamella. The G. gecko 's seta is modelled using inextensible fibril based on Euler's elastica theorem. Considering the side contact of the spatular pads of the seta on the flat and rigid substrate, the directional adhesion behaviour of the seta has been investigated. The lamella-induced attachment and detachment have been modelled to simulate the active digital hyperextension (DH) and the digital gripping (DG) phenomena. The results suggest that a tiny angular displacement within 0.25° of the lamellar proximal end is necessary in which a fast transition from attachment to detachment or vice versa is induced. The active DH helps release the torque to induce setal non-sliding detachment, while the DG helps apply torque to make the setal adhesion stable. The lamella plays a key role in saving energy during detachment to adapt to its habitat and provides another adhesive function which differs from the friction-dependent setal adhesion system controlled by the dynamic of G. gecko 's body.

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Qin, Xin-min, Fang Qian, De-long Zeng, Xiao-can Liu, and Hui-min Li. "Complete mitochondrial genome of the red-spotted tokay gecko (Gekko gecko, Reptilia: Gekkonidae): Comparison of red- and black-spotted tokay geckos." Mitochondrial DNA 22, no. 5-6 (October 2011): 176–77. http://dx.doi.org/10.3109/19401736.2011.636440.

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Kurniawan, Nia, Amir Hamidy, and Ari Ardiantoro. "Evaluation on the Legal Trade of Tokay gecko (Lacertidae; Gekkonidae; Gekko gecko Linnaeus, 1758) in Indonesia." Journal of Tropical Life Science 11, no. 1 (February 3, 2021): 93–100. http://dx.doi.org/10.11594/jtls.11.01.12.

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Tokay gecko (Gekko gecko) is a large-sized gecko from the genus of Gekko, which is most commonly found from South Asia, southern China, and Southeast Asia. In Indonesia, these species are common to inhabit human-modified habitat in Sumatera, Borneo, Java, Bali, Lesser Sundas, Sulawesi, and Moluccas. In recent years, the demand for Tokay gekko with high use-value in both national and international markets has increased, one of which is used for traditional medicine. This situation raised the concern on the decreasing of the wild population and the validity of captive breeding programs that produced a large number of individuals. Several reports had estimated millions of individuals have been exported from Indonesia either legally or illegally, however, the exact number never been reported. The purpose of this study is to evaluate the trend on the harvested Tokay gecko and its origin based on the source code information. The data were collected from government records, including specimens harvested from the wild and specimens produced from captivity during 2013 - 2018 (six years). The results showed that the legally exported specimens were sourced from wild (W) and captive breeding (C or F). The total numbers of individuals exported from the wild harvest are 97.146, and all export realization is below the wild harvest quota. However, there are the large numbers of individuals exported and declared as specimens produced from the captive breeding facilities (6.965.000 with source code F, and 1.236.000 with source code C). More importantly, the high level of specimens produced from captive breeding facilities is unlikely to match with the biological capacity of this species. Therefore, we predict that specimens labeled captive breeding were likely sourced from the wild.

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Laver, Rebecca J., Cristian H. Morales, Matthew P. Heinicke, Tony Gamble, Kristin Longoria, Aaron M. Bauer, and Juan D. Daza. "The development of cephalic armor in the tokay gecko (Squamata: Gekkonidae: Gekko gecko )." Journal of Morphology 281, no. 2 (December 28, 2019): 213–28. http://dx.doi.org/10.1002/jmor.21092.

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Jiang, Jianping, Juan Huo, Yueyun Zhang, Yongli Xu, Chengjian Zhao, and Jianhua Miao. "SMRT sequencing of the full-length transcriptome of Gekko gecko." PLOS ONE 17, no. 2 (February 25, 2022): e0264499. http://dx.doi.org/10.1371/journal.pone.0264499.

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Tokay Gecko (Gekko gecko) is a rare and endangered medicinal animal in China. Its dry body has been used as an anti-asthmatic agent for two thousand years. To date, the genome and transcriptome of this species remain poorly understood. Here, we adopted single molecule real-time (SMRT) sequencing to obtain full-length transcriptome data and characterized the transcriptome structure. We identified 882,273 circular consensus (CCS) reads, including 746,317 full-length nonchimeric (FLNC) reads. The transcript cluster analysis revealed 212,964 consensus sequences, including 203,994 high-quality isoforms. In total, 111,372 of 117,888 transcripts were successfully annotated against eight databases (Nr, eggNOG, Swiss-Prot, GO, COG, KOG, Pfam and KEGG). Furthermore, 23,877 alternative splicing events, 169,128 simple sequence repeats (SSRs), 10,437 lncRNAs and 7,932 transcription factors were predicted across all transcripts. To our knowledge, this report is the first to document the G. gecko transcriptome using SMRT sequencing. The full-length transcript data might accelerate transcriptome research and lay the foundation for further research on G. gecko.

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Kennedy, Murray J., L. M. Killick, and M. Beverley-Burton. "The prevalence of Paradistomum geckonum, Mesocoelium sociale, and Postorchigenes ovatus (Digenea) in lizards (Sauria) from Indonesia." Canadian Journal of Zoology 65, no. 5 (May 1, 1987): 1292–94. http://dx.doi.org/10.1139/z87-204.

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Three species of Digenea were found in collections of seven species of lizards from Indonesia from May 1978 to February 1979: Paradistomum geckonum Bhalerao, 1929 (Dicrocoeliidae) was found in the gallbladder and bile duct of Hemidactylus frenatus, Cosymbotus platyurus, Gehyra mutilata, Gekko gecko, Calotes versicolor, and Takydromus sexlineatus; Mesocoelium sociale Lühe, 1901 (Mesocoeliidae) in the small intestine and stomach of H. frenatus, C. platyurus, G. gecko, C. versicolor, and Mabuya multifasciata; and Postorchigenes ovatus Tubangui, 1928 (Lecithodendriidae) in the small intestine of H. frenatus, C. platyurus, G. mutilata, and G. gecko. Data on prevalence, intensity, and location within the host are given for each digenean species. No variations were observed between wet and dry seasons. Prevalence and intensity of P. geckonum and P. ovatus were similar in males and females of each host species examined except for the gecko Gehyra mutilata, in which females had a significantly higher prevalence of infection of both parasites than males. This difference is possibly due to differential food preference.

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Griffing, Aaron H., Thomas J. Sanger, Lilian Epperlein, Aaron M. Bauer, Anthony Cobos, Timothy E. Higham, Emily Naylor, and Tony Gamble. "And thereby hangs a tail: morphology, developmental patterns and biomechanics of the adhesive tails of crested geckos ( Correlophus ciliatus )." Proceedings of the Royal Society B: Biological Sciences 288, no. 1953 (June 16, 2021): 20210650. http://dx.doi.org/10.1098/rspb.2021.0650.

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Among the most specialized integumentary outgrowths in amniotes are the adhesive, scale-like scansors and lamellae on the digits of anoles and geckos. Less well-known are adhesive tail pads exhibited by 21 gecko genera. While described over 120 years ago, no studies have quantified their possible adhesive function or described their embryonic development. Here, we characterize adult and embryonic morphology and adhesive performance of crested gecko ( Correlophus ciliatus ) tail pads. Additionally, we use embryonic data to test whether tail pads are serial homologues to toe pads. External morphology and histology of C . ciliatus tail pads are largely similar to tail pads of closely related geckos. Functionally, C . ciliatus tail pads exhibit impressive adhesive ability, hypothetically capable of holding up to five times their own mass. Tail pads develop at approximately the same time during embryogenesis as toe pads. Further, tail pads exhibit similar developmental patterns to toe pads, which are markedly different from non-adhesive gecko toes and tails. Our data provide support for the serial homology of adhesive tail pads with toe pads.

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Kurniati, Hellen, and Ni Luh Putu Rischa Phadmacanty. "Age and Body Growth of the Tokay Gecko, <i>Gekko gecko</i> (Linnaeus, 1758), Studied by the Skeletochronological Method." Russian Journal of Herpetology 29, no. 3 (June 28, 2022): 161–68. http://dx.doi.org/10.30906/1026-2296-2022-29-3-161-168.

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Tokay gecko, Gekko gecko (Linnaeus, 1758) is highly exploited in Java for human consumption in China. Using skeletochronology, the age and body growth of Tokay Geckos from local populations in Central Java (18 females, 21 males) and in East Java (19 females, 42 males) were studied for the first time. A total of 100 frozen specimens (37 females, 63 males) were used. Sex was determined by observing the presence (male) or absence of pre-anal pores (female). Snout to vent length (SVL) of the smallest female and male with the line of arrested growth (LAG) was 127.1 and 160.4 mm, respectively. Both males and females reach sexual maturity before one year old with 98.3 mm SVL for females and 111.6 mm SVL for males. Analysis of the LAG counts indicated that the age of individuals that were harvested was ranged 0 – 2 years for females and males, with SVL ranging 110 – 182 mm. Growth rates in SVL are much faster in males as compared to females, as well as increasing of MP (width of bone from the edge of marrow cavity to the periosteal outer margin) inside femur bone. The mean SVL of males was larger than that of females. The Sexual Dimorphism Index (SDI) was calculated as -0.28, indicating a sexual size dimorphism in favor of males.

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Powell, Robert, Robert Henderson, Cory Lindsay, and Saul Nava. "Microhabitat, activity, and density of a dwarf gecko (Sphaerodactylus parvus) on Anguilla, West Indies." Amphibia-Reptilia 22, no. 4 (2001): 455–64. http://dx.doi.org/10.1163/15685380152770417.

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AbstractSphaerodactylus parvus is a dwarf gecko endemic to the Anguilla Bank in the Lesser Antilles, West Indies. Aspects of S. parvus ecology were studied at six sites on Anguilla. Geckos were encountered most frequently in association with rock spills, and gecko population densities (0-5.2/m2) were correlated positively with rock densities. A disproportionate number of rocks which harbored S. parvus were on complex substrates of smaller rocks, leaf litter, and small sticks. Geckos became active in the late afternoon and early evening (after air temperature dropped below under-rock temperature). Activity peaked between 1900 h and 2100 h, but S. parvus was active in leaf litter until at least shortly past midnight. Potential problems associated with field studies of these diminutive gekkonids are discussed.

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Brown, Susan, Deborah Ishii-Thoene, Roanne Lebrun, and Jacqueline Yamasaki. "INDIRECT COMPETITION BETWEEN A RESIDENT UNISEXUAL AND AN INVADING BISEXUAL GECKO." Behaviour 139, no. 9 (2002): 1161–73. http://dx.doi.org/10.1163/15685390260437317.

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AbstractEstablished populations of the unisexual gecko, Lepidodactylus lugubris, decline around man-made lights when the bisexual gecko, Hemidactylus frenatus, invades the environment. Some of the decline in L. lugubris numbers could occur through the process of exploitative competition for food resources. Our experiments were designed to see if other variables were important in the decline. We found that L. lugubris were more likely to use a hiding platform in enclosures with 2 rather than 1 platform when conspecific or heterospecific pairs of geckos were housed in an enclosure. Additionally, when two H. frenatus were housed in the same enclosure, they maintained closer proximity to each other than when their cagemates were L. lugubris. L. lugubris developed and laid more eggs when housed with another L. lugubris than when housed with either a female or male H. frenatus. Most interestingly, L. lugubris housed in enclosures previously occupied by H. frenatus males required more time for egg development and laying than geckos housed in enclosures previously occupied by another L. lugubris. In conclusion, variables in addition to food competition may influence the declines in L. lugubris numbers when an area in which they are established is invaded by the bisexual gecko, H. frenatus. L. lugubris numbers may decline in response to their reluctance to share a hiding place with another gecko, leaving them more vulnerable to predators. Additionally, L. lugubris fecundity may be negatively affected by the exudates from H. frenatus femoral pores or the odors of their feces.

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Kurniati, Hellen, and Ni Luh Putu Rischa Phadmacanty. "Macro and Micro-anatomy of Tokay Gecko’s Reproduction Organs and Growth of External Body in Support on Reproduction Activities (Squamata: Gekkonidae: Gekko gecko)." Jurnal Veteriner 22, no. 3 (September 30, 2021): 429–41. http://dx.doi.org/10.19087/jveteriner.2021.22.3.429.

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Tokay gecko, Gekko gecko is an oviparous lizard that is distributed very widely in tropical Asia. The sexual maturity stage of tokay gecko does not have seasonal reproductive activity; they reproduce along the year. The study on the reproduction organ and growth of external morphology of tokay gecko is the first contribution to further scientific information. Gonadal micro-anatomy that were shown by histology and macro-anatomy to include the sex accessories could be demonstrated in this lizard as a criteria for the reproductive activity of urogenital organs. Males and females tokay gecko have simple urogenital track systems and also the males have simple hemipenis morphology. Testes position inside the male body is not symmetric, in the right testis is always in a higher position than left testis. Based on analysis of the measurement of the posterior part of the body, the width of cloaca, width of base tail and length of hind limb increase asymptotic growth on snout to vent length (SVL) SVL?130 mm for females, and SVL?150 mm for males. Asymptotic growth in the posterior part of the male and female body is a form of co-evolution, besides the male urogenital organs and the female reproductive system which also support co-evolution in the reproductive organs.

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Kim, Tae Wan, and Bharat Bhushan. "The adhesion model considering capillarity for gecko attachment system." Journal of The Royal Society Interface 5, no. 20 (June 26, 2007): 319–27. http://dx.doi.org/10.1098/rsif.2007.1078.

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Geckos make use of approximately a million microscale hairs (setae) that branch off into hundreds of nanoscale spatulae to cling to different smooth and rough surfaces and detach at will. This hierarchical surface construction gives the gecko the adaptability to create a large real area of contact with surfaces. It is known that van der Waals force is the primary mechanism used to adhere to surfaces, and capillary force is a secondary effect that can further increase adhesive force. To investigate the effects of capillarity on gecko adhesion, we considered the capillary force as well as the solid-to-solid interaction. The capillary force expressed in terms of elliptical integral is calculated by numerical method to cope with surfaces with a wide range of contact angles. The adhesion forces exerted by a single gecko spatula in contact with planes with different contact angles for various relative humidities are calculated, and the contributions of capillary force to total adhesion force are evaluated. The simulation results are compared with experimental data. Finally, using the three-level hierarchical model recently developed to simulate a gecko seta contacting with random rough surface, the effect of the relative humidity and the hydrophobicity of surface on the gecko adhesion is investigated.

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Hemmer, Helmut, and Rudolf Schipp. "Zum Beutefangverhalten des Tokehs (Gekko gecko L.)." Zeitschrift für Tierpsychologie 27, no. 5 (April 26, 2010): 591–609. http://dx.doi.org/10.1111/j.1439-0310.1970.tb01888.x.

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Journal articles on the topic 'Gecko'

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