Hemidactylus Research Articles

Alizarin Red S-Alcian Blue Staining for Regenerated tail of Common House Gecko (Hemidactylus frenatus)

Common House Gecko (Hemidactylus frenatus) is one of reptiles that have ability to autotomy their tails. Tail autotomy is a mechanism to protect it self from predators. After the tail broke, there will be wound healing on the tail which is then followed by a tail regeneration event. Original tail and regenerate tail is very different morphologically and anatomically. The original tail is composed of bones while the tail of the regenerate is composed of cartilage. Histochemical staining using Alizarin Red-S Alcian Blue was done to differentiate bone and cartilage. This method will stained bones red while the cartilage will stained blue.

Inherent variations in the cellular events at the site of amputation orchestrate scar-free wound healing in the tail and scarred wound healing in the limb of lizard Hemidactylus flaviviridis.

Lizards are unique in having both-regeneration competent (tail) as well as non-regenerating appendages (limbs) in adults. They therefore present an appropriate model for comparing processes underlying regenerative repair and nonregenerative healing after amputation. In the current study, we use northern house gecko Hemidactylus flaviviridis to compare major cellular and molecular events following amputation of the limb and of the tail. Although the early response to injury in both cases comprises apoptosis, proliferation, and angiogenesis, the temporal distribution of these processes in each remained obscure. In this regard, observations were made on the anatomy and gene expression levels of key regulators of these processes during the healing phase of the tail and limb separately. It was revealed that cell proliferation markers like fibroblast growth factors were upregulated early in the healing tail, coinciding with the growing epithelium. The amputated limb, in contrast, showed weak expression of proliferation markers, limited only to fibroblasts in the later stage of healing. Additionally, apoptotic activity in the tail was limited to the very early phase of healing, as opposed to that in the limb, wherein high expression of caspase-3 was observed throughout the healing process. Early rise in VEGF-α expression reflected an early onset of angiogenesis in the tail, while it was seen to occur at a later stage in case of the limb. Moreover, the expression pattern of transforming growth factor beta members points toward a pro-fibrotic response being induced very early in the amputated limb. Collectively, these results explain why regenerating appendages are able to heal without scars and if we are to induce scar-free healing in nonregenerating limbs, what interventions can be envisaged. This is crucial to the field of regenerative medicine since it is the initial stages of repair following amputation, which decide whether the appendage will be restored or only covered with a scab.

Confirming the presence of a fourth species of non-native house gecko of the genus Hemidactylus Oken, 1817 (Squamata, Gekkonidae) in Colombia

The Indo-Pacific Gecko, Hemidactylus garnotii Duméril & Bibron, 1836, is a species of house gecko native to Southeast Asia and Pacific Islands. As with many of its congeners, this gecko species has been accidentally introduced to other parts of the world. In January 2018, several photographs of “H. frenatus” from Colombia posted in iNaturalist.org, were noticed to have some morphological features related to H. garnotii. This discrepancy led us to inspect museum specimens and to confirm the presence of H. garnotii for more than a decade in Colombia.

A Record of an Asian House Gecko, Hemidactylus frenatus, from Laos as a Host of the Pentastome, Kiricephalus pattoni, with Comments on the Distribution and Natural History of This Parasite

Abstract An Asian house gecko (Hemidactylus frenatus Schlegel, 1836) was collected in a forested area near the town of Thakhek, Laos. Inspection of the lizard revealed that it had a subcutaneous lump on its abdomen, which was determined to be caused by a nymph of the pentastome Kiricephalus pattoni (Stephens, 1908). Although H. frenatus has been recorded as a host of K. pattoni in Taiwan, Thakhek, Laos represents a new distribution record for this parasite.

Population Viability of Nonnative Mediterranean House Geckos (Hemidactylus turcicus) at an Urban Site Near the Northern Invasion Front

Abstract Biological invasions are one of the most serious threats to biodiversity conservation. Although success and impacts of many invaders, particularly ectotherms, are likely to be limited by a combination of climatic and demographic factors, human modifications to the environment can facilitate distributional expansion into otherwise low-quality landscapes. We assessed factors that might promote or preclude population viability of a nonnative ectotherm, Hemidactylus turcicus (Mediterranean House Gecko), within an urban center at the northern periphery of its known North American range. Mediterranean House Geckos are increasingly apparent in the southeastern United States, but their potential for establishment and spread in more temperate regions is less well known. We gathered data using capture–recapture methods and the unique dorsal patterns of individual geckos. Despite a more temperate climate compared to other areas in their introduced range, and refuge temperatures falling below the critical th...

Sex-specific thermal sensitivities of performance and activity in the asian house gecko, Hemidactylus frenatus.

Studies of sexual selection primarily focus on morphological traits such as body size and secondary trait dimorphism, with less attention been given to the functional differences between the sexes and even more so their thermal performance capacities. Each sex may benefit from possessing different thermal performance capacities that would allow them to maximise their fitness relative to their different reproductive roles; especially when performances are closely related to reproductive success. Here, we examine sexual divergence in thermal sensitivities of performance across three populations of the Asian house gecko (Hemidactylus frenatus) over an extensive latitudinal cline. Using analyses of the thermal sensitivity of routine activity, bite force and sprint speed, we explored whether: (i) males and females differed in their optimal temperatures for performance, (ii) the sexes differed in their thermal sensitivities of performance, and (iii) the degree of sexual divergence in thermal sensitivity varied among the populations. Because male H. frenatus are highly aggressive and frequently engage in combat to gain territories and mating opportunities, we expected males would be active over a wider range of temperatures than females and this would favour broad thermal sensitivity curves for males. In addition, we expected a greater divergence between the sexes in thermal sensitivities for the temperate populations that experience greater daily and seasonal thermal variation. We found that males were more active, and had greater bite forces and faster sprint speeds than females, independent of body size. In addition, we found differences between the sexes in thermal sensitivities for the tropical population; female H. frenatus were less active and possessed lower sprint speeds at higher temperatures than males. Although H. frenatus from the most variable thermal environments also displayed the broadest thermal performance range, it was the more stable tropical population that exhibited the greatest divergence between the sexes in thermal sensitivity of performance. The divergence in thermal physiology that we detected between the sexes of H. frenatus is consistent with the idea that males will derive mating and territorial advantages for maintaining function over a broader range of temperatures.

The impact of parasites during range expansion of an invasive gecko.

Host-parasite dynamics can play a fundamental role in both the establishment success of invasive species and their impact on native wildlife. The net impact of parasites depends on their capacity to switch effectively between native and invasive hosts. Here we explore host-switching, spatial patterns and simple fitness measures in a slow-expanding invasion: the invasion of Asian house geckos (Hemidactylus frenatus) from urban areas into bushland in Northeast Australia. In bushland close to urban edges, H. frenatus co-occurs with, and at many sites now greatly out-numbers, native geckos. We measured prevalence and intensity of Geckobia mites (introduced with H. frenatus), and Waddycephalus (a native pentastome). We recorded a new invasive mite species, and several new host associations for native mites and geckos, but we found no evidence of mite transmission between native and invasive geckos. In contrast, native Waddycephalus nymphs were commonly present in H. frenatus, demonstrating this parasite's capacity to utilize H. frenatus as a novel host. Prevalence of mites on H. frenatus decreased with distance from the urban edge, suggesting parasite release towards the invasion front; however, we found no evidence that mites affect H. frenatus body condition or lifespan. Waddycephalus was present at low prevalence in bushland sites and, although its presence did not affect host body condition, our data suggest that it may reduce host survival. The high relative density of H. frenatus at our sites, and their capacity to harbour Waddycephalus, suggests that there may be impacts on native geckos and snakes through parasite spillback.

Reptiles and Amphibians as Potential Reservoir Hosts of Chikungunya Virus.

Chikungunya virus is an emerging arbovirus of significant human-health concern. Little is known about its sylvatic cycle, including whether ectothermic vertebrates are permissive to infection. In this study, individuals from ten species of reptiles and amphibians were inoculated with chikungunya virus and samples of blood were tested to characterize viremia and seroconversion. Viremia was not detected in cane toads, house geckos, or American alligators, but most of the green iguanas, red-eared sliders, ball and Burmese pythons, leopard frogs, Texas toads, and garter snakes developed viremia. Peak virus titers in serum of up to 4.5, 4.7, and 5.1 log10 plaque-forming units per milliliter were observed for garter snakes, ball pythons, and Texas toads, respectively. These results add to those of other studies that have suggested a possible role for ectothermic vertebrates in the ecology of arbovirus maintenance and transmission in nature.

Pharyngodon frenatusiin Brooks’ House Gecko,Hemidactylus brookiiGray, 1845, and Flat-tailed House GeckoHemidactylus platyurus(Schneider, 1797) from Kirtipur, Nepal

Abstract Pharyngodon frenatusi (Nematoda: Pharyngodonidae) is reported from Brooks’ house gecko, Hemidactylus brookii, and flat-tailed house gecko, Hemidactylus platyurus, from Kirtipur, Nepal. Fifteen samples of H. brookii and 10 H. platyurus were collected in 2014 and examined for helminth parasites. Pharyngodon frenatusi was found in great numbers in the intestines of both hosts. The prevalence of P. frenatusi in H. brookii was 73%, and in H. platyurus, it was 80%. This is the first report, to our knowledge of P. frenatusi reported in house geckoes of Nepal. Hemidactylus platyurus represents a new host record for P. frenatusi.

Invasive house geckos (hemidactylus spp.): their current, potential and future distribution

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Depredación de Hemidactylus mabouia (Squamata: Gekkonidae) or Tropidophis pardalis (Serpentes: Tropidophiidae)

Se registra por primera vez la depredación, en vida libre, de la salamanquesa Hemidactylus mabouia (Moreau de Jonnés, 1818) por el Majacito Bobo Tropidophis pardalis (Gundlach, 1840). Además, se mencionan otros dos vertebrados, el lagarto Anolis porcatus Gray, 1841 (Squamata: Dactyloidae) y la ranita Eleutherodactylus planirostris (Cope, 1862), como presas de esta pequeña boa en la misma localidad.

Invasive house geckos (hemidactylus spp.): their current, potential and future distribution.

In this study, we identified the current distribution of five globally distributed invasive Hemidactylus species and predicted their potential and future distribution using species distribution models based on climate and elevation data. These species included H. brookii, H. frenatus, H. garnotii, H. mabouia, and H. turcicus. We show that many regions with tropical and Mediterranean climates are suitable for most of these species. However, their current and potential distributions suggest that climate is not the only limiting factor. We hypothesize that climatic conditions may affect competition and other interactions resulting in a segregated distribution of the studied Hemidactylus species. As an effect of global climate change it is likely that H. brookii will expand its range to areas that are currently colonized by H. mabouia and/or H. frenatus, while H. turcicus is likely to expand its range to areas that are not yet invaded by any Hemidactylus species. The role of species interactions in the range expansion of these five Hemidactylus species still remains poorly understood, but could be of major importance in understanding and managing these invasive species.

Venom phenotypes of the Rock Rattlesnake (Crotalus lepidus) and the Ridge-nosed Rattlesnake (Crotalus willardi) from México and the United States

Although the Mexican Highlands has the highest diversity of small-bodied rattlesnakes in the world, studies on the species found throughout this region have been relatively scarce. This has led to challenges with examining venom phenotypic characteristics, as well as species misidentifications and misclassifications. In the current study we investigated venom variation among four subspecies of Crotalus lepidus (C. l. klaluberi, C. l. lepidus, C. l. maculosus, C. l. morulus) and four subspecies of C. willardi (C. w. amabilis, C. w. obscurus, C. w. silus, and C. w. willardi) that inhabit regions of southwestern United States and central México. SDS-PAGE patterns show the presence of many of the major compounds found in other rattlesnake venoms, although minor variations in protein banding patterns and intensity are recognizable. Most notably, PI-metalloproteinase (SVMP) bands appear to be very faint to absent in northern C. l. lepidus and C. l. klauberi subspecies, but are fairly prominent in all other C. lepidus and C. willardi subspecies. Enzyme activity assays revealed that C. lepidus subspecies exhibit higher SVMP and thrombin-like activities when compared to C. willardi subspecies. Significant differences between subspecies were also observed for kallikrein-like serine protease, L-amino acid oxidase, and phosphodiesterase activities, although these differences appear to be random and fail to follow a geographical or phylogenetic trend. The same relationship was also observed for fibrinogenolytic and coagulation assays. Toxicity assays conducted on lab mice (Mus musculus), house geckos (Hemidactylus frenatus), and house crickets (Acheta domestica) revealed varying toxicities between subspecies, with C. l klauberi being the most toxic towards mice (LD50 = 1.36 μg/g) and house geckos (LD50 = 0.17 μg/g), and C. w. silus being most toxic to house crickets (LD50 = 1.94 μg/g). These results provide additional evidence that geographical isolation, natural selection, and adaptive evolution in response to diets may be driving forces contributing to population-level variation in venom composition.

Emergent multisystemic Enterococcus infection threatens endangered Christmas Island reptile populations.

Multisystemic infections with a morphologically unusual bacterium were first observed in captive critically endangered Lister’s geckos (Lepidodactylus listeri) on Christmas Island in October 2014. Since then the infection was identified in another captive critically endangered lizard species, the blue-tailed skink (Cryptoblepharus egeriae) and two species of invasive geckos; the four clawed gecko (Gehyra mutilata) and Asian house gecko (Hemidactylus frenatus), in a wide geographic range across the east side of the island. The Gram and periodic acid-Schiff positive cocci to diplococci have a propensity to form chains surrounded by a matrix, which ultrastructurally appears to be formed by fibrillar capsular projections. The bacterium was associated with severe and extensive replacement of tissues, but minimal host inflammatory response. Attempts to grow the organism in culture and in embryonated eggs were unsuccessful. Molecular characterisation of the organism placed it as a novel member of the genus Enterococcus. Disease Risk Analyses including this organism should now be factored into conservation management actions and island biosecurity.

Molecular identification of Thelandros scleratus and Thelastoma icemi (Nematoda: Oxyruida) using mitochondrial cox 1 sequences.

Two species of parasitic nematodes collected from the intestine of Brook's House Gecko, Hemidactylus brooki and American cockroach, Periplaneta americana L. The parasites were identified as Thelandros scleratus and Thelastoma icemi by PCR amplification method. Subsequently, sequence analysis of mt cox1 (504 and 540 bp) for T. scleratus and T. icemi respectively revealed that these sequences showed maximum similarity of 90% (in case of T. scleratus), 77% (in case of T. icemi), to nematode sequences available on GenBank. To our knowledge, no cox1 sequence is available for both the species of family Pharyngodonidae and Thelastomatidae. This study represents the first mitochondrial DNA characterization of both species.

Histological Study of Common House Gecko (Hemidactylus frenatus) Regenerated Tail

Common house gecko<strong> </strong>(<em>Hemidactylus frenatus</em>) belongs to suborder Lacertilia that has capacity to shed its tail (autotomy) as a self-defense mechanism. After autotomy, tail regeneration occurs. Axiale skeleton of an original tail is composed of bony vertebrae, whereas the the regenerate one is comprised of cartilaginous tube. The purpose of this study was to determine the histological difference between axial skeleton of the original tail and the regenerate one of the common house gecko. Twenty four individuals consist of twelve common house gecko with original tail and twelve with regenerate tail were used. Microanatomical observations were carried on histological slide of original and regenerated tail stained with Hematoxylin-Eosin and Mallory Acid Fuchsin. The results showed that the original tail comprised of bony vertebrae whereas regenerated tail supported by cartilaginous tube.

Predation on a tropical house gecko, Hemidactylus mabouia by a juvenile colubrid snake, Chironius bicarinatus, in a Brazilian Atlantic Rainforest area.

Snakes in the Neotropical genus Chironius are mainly batrachophagous, and tend to consume relatively small prey. We present a report of a juvenile Chironius bicarinatus that had ingested a house gecko ( Hemidactylus mabouia ) corresponding to ca. 62% of its preserved body mass. The ingestion of such a large prey item is unusual for a snake of the genus Chironius , as is the consumption of lizards. Consumption of unusually large prey items may be more common in young snakes than in adults, possibly due to a lower availability of prey of appropriate size and/or to a lower capacity to evaluate the size of potential prey.

Intraspecific competition, not predation, drives lizard tail loss on islands.

Tail autotomy is mainly considered an antipredator mechanism. Theory suggests that predation pressure relaxes on islands, subsequently reducing autotomy rates. Intraspecific aggression, whichmay alsocausetail loss,probably intensifies on islands due to the higher abundance. We studied whether tail autotomy is mostly affected by predation pressure or by intraspecific competition. We further studied whether predator abundance or predator richness is more important in this context. To test our predictions, we examined multiple populations of two gecko species: Kotschy's gecko(Mediodactylus kotschyi; mainland and 41 islands) andthe Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundance together with five indices of predation. In both species, autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M.kotschyi, tail-loss rates are higher on predator and viper-free islands, but increase with viper abundance. We suggest that autotomy is not simply, or maybe even mainly, an antipredatory mechanism. Rather, such defence mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail autotomy in insular populations, chiefly to intraspecific aggression.

Range extension and distribution of the invasive Moreau’s Tropical House Gecko, Hemidactylus mabouia (Moreau de Jonnès, 1818) (Squamata: Gekkonidae), in Suriname

We document a population of Moreau’s Tropical House Gecko, Hemidactylus mabouia (Moreau de Jonnès, 1818), at a remote Amerindian village, Kwamalasamutu, Suriname, South America. This village is approximately 370 km southwest of the northern coastal region where the presence of H. mabouia was previously recorded. Numerous individuals and a gravid female provide evidence of a viable population. The morphological characters of the two female specimens examined fall within the range of characters recorded from African and Ascension Island specimens. Due to its overland inaccessibility, we believe that colonization occurred anthropogenically through air or boat transport from the coastal region.

Disentangling the Influence of Urbanization and Invasion on Endemic Geckos in Tropical Biodiversity Hot Spots: A Case Study ofPhyllodactylus martini(Squamata: Phyllodactylidae) along an Urban Gradient in Curaçao

Predicting the response of endemic species to urbanization has emerged as a fundamental challenge in 21st century conservation biology. The factors that underlie population declines of reptiles are particularly nebulous, as these are often the least understood class of vertebrates in a given community. In this study, we assess correlations between feeding ecology and phenotypic traits of the Lesser Antillean endemic Dutch leaf-toed gecko, Phyllodactylus martini, along an urban gradient in the Caribbean island of Curacao. There has been a marked decline of this species in developed habitats associated with the invasive tropical house gecko Hemidactylus mabouia. We find a correlation between aspects of locomotor morphology and prey in undeveloped habitats that is absent in developed habitats. Analyses of stomach contents further suggest that Phyllodactylus martini alters primary prey items in developed areas. However, changes in prey promote the overlap in foraging niches between Phyllodactylus martini and Hemidactylus mabouia, suggesting that direct resource competition is contributing to the decline of Phyllodactylus martini. In addition to competitive exclusion, we suggest that the urban extirpation of Phyllodactylus martini could also be attributed to a top-down control on population growth by Hemidactylus mabouia. Colonizations of walls put Phyllodactylus martini in direct contact with Hemidactylus mabouia increasing the chances for predation events, as evidenced by our observation of a predation event on a Phyllodactylus martini juvenile by an adult Hemidactylus mabuoia. In total, our results add to a growing body of literature demonstrating the threat that invasive synanthropic reptiles pose to endemics that might otherwise be able to cope with increased urbanization pressures.