Garden Lizard Calotes Versicolor Research Articles

Invasive risk assessment and expansion of the realized niche of the Oriental Garden Lizard Calotes versicolor species complex (Daudin, 1802)

Correlative species distribution modelling (SDM) can be a useful tool to quantify a species’ realized niche and to predict its potential distribution for non-native ranges. The agamid lizard Calotes versicolor s.l. belongs to the most widely distributed reptile taxa worldwide. In the past, C. versicolor s.l. has been introduced to several countries, including regions in the Oriental, the Neotropical and the Afrotropical realms, where strong negative impact on the local fauna is assumed. Due to the complicated taxonomy and the existence of several cryptic species, which are covered by this taxon, we used C. versicolor sensu lato and its four subtaxa (C. versicolor sensu stricto, C. irawadi, C. vultuosus, C. farooqi) as target species to (1) compute correlative SDMs for C. versicolor s.l. and its subtaxa and project them across the globe to highlight climatically suitable areas of risk for future invasion and (2) based on the ecological niche concept, we investigate if the species complex expanded its realized climatic niche during the invasion process. We use two different SDM approaches, namely n-dimensional hypervolumes and Maxent. N-dimensional hypervolumes are a non-hierarchically ranked approach, which is a useful tool to investigate the expansion in the realized niche, while Maxent, a hierarchically ranked model, is used to focus on potentially suitable areas for future invasion. We calculated two final models for C. versicolor s.l., one based on records from the native range and one based on records from the native and invaded range, as well as one model for each subtaxon. Our results show a geographic expansion into novel climatic conditions as well as an expansion in the realized niche. Our results reveal that C. versicolor s.l. is currently inhabiting 13% of its potential range but could find suitable climatic conditions on a global surface area between 14,025,100 km2 and 53,142,600 km2. Our predictions reveal large areas of highly suitable climatic conditions for the Oriental, Australian, Afrotropical and Neotropical realms, whereas only small regions of the Palearctic and Nearctic realms provide moderately suitable conditions. Further, some localities, especially those with a high amount of human traffic like ports or airports, might act as multiplicators and might therefore be a stepping stone into further areas.

Vertebrate prey handling in the Indian Grey Hornbill Ocyceros birostris (Aves: Bucerotiformes: Bucerotidae)

Most hornbills are omnivorous, but there are few specific records of how vertebrate prey are handled by hornbills, particularly in Asia. I describe an observation of a pair of Indian Grey Hornbills Ocyceros birostris handling a large vertebrate prey item (Garden Lizard Calotes versicolor) which included both manipulation (crushing) in the bill and repeated wiping on the branch of a tree, the latter technique undescribed for this or other species of hornbill. Likely reasons for this behaviour are discussed.

Proteinaceous sperm motility inhibitory factor from the female Indian garden lizard Calotes versicolor.

Female sperm storage is an intriguing adaptation exhibited by a wide array of both vertebrates and invertebrates. The mechanisms underlying female sperm storage have remained elusive. Using the Indian garden lizard Calotes versicolor as a model organism, we investigated the role of low and high molecular weight factors in this phenomenon. Previously, we demonstrated three distinct phases of the reproductive cycle in this animal with live, motile spermatozoa recovered from the uterovaginal region during the reproductive phase. In the present study, we analysed the uterovaginal contents using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified an abundant protein band corresponding to ~55 kDa regardless of the phase of the reproductive cycle. Analysis of the purified protein by liquid chromatography-tandem mass spectrometry suggested a unique protein without any homology to the National Center for Biotechnology Information database. Exogenous addition of this protein to washed spermatozoa derived from the epididymis reversibly inhibited sperm motility in a concentration- and time-dependent manner, suggesting it plays a key role in sperm storage. These studies are likely to offer new avenues to unravel the secrets of female sperm storage seen across the animal taxa and may have novel applications not only in reproductive biology, but also in general cell storage and preserving endangered animal species.

Calcitonin-induced alterations to the ultimobranchial and parathyroid glands in the garden lizard Calotes versicolor

Calotes versicolor specimens were divided into 2 groups of equal quantity (groups A and B). Group A was injected daily with 0.1 mL/50 g bw of vehicle. Group B was injected daily with 0.5 \mug/50 g bw of salmon calcitonin. Lizards in each group were sacrificed 2 h after the last injection on the 1st, 3rd, 5th, 10th, and 15th day of treatment. After collection of blood samples, ultimobranchial and parathyroid glands were fixed. The plasma calcium level in the lizards treated with calcitonin decreased on day 1. This response progressed up to day 5; thereafter the level was elevated, so that on day 15 a normal plasma calcium level was achieved. No change in plasma phosphate levels from day 1 was observed following calcitonin treatment. Progressive hypophosphatemia was observed from day 3 to 5; thereafter the level tended to rise and resulted in normophosphatemia on day 15. The ultimobranchial gland in the lizards treated with calcitonin did not exhibit any histological alterations up to day 5. The nuclear volume of ultimobranchial cells decreased on day 10 and persisted until day 15. Additionally, few degenerating cells were observed after 15 days of calcitonin treatment. The parathyroid gland in C. versicolor was unaffected up to day 3 following calcitonin treatment. A progressive increase in the nuclear volume of parathyroid cells was observed from day 5 until the end of the experiment (day 15); the gland became compact on days 10 and 15. In addition, few degenerating cells were observed after 15 days of calcitonin treatment.

Behavioural ecology of a tea pest, Andraca bipunctata (Lepidoptera: Bombycidae), in the Sub-Himalayan climate of Darjeeling (India)

Behavioural ecology of a tea pest, Andraca bipunctata (Lepidoptera: Bombycidae), in the Sub-Himalayan climate of Darjeeling (India) The summer generation (G1) of Andraca bipunctata Walker in Darjeeling was confined to May-December and the winter generation (G2) extended from August to June. One female laid on average 480 and 526 eggs in G1 and G2, respectively. Larvae fed on Camellia sinensis and C. assamica leaves. Duration of 1st, 2nd, 3rd, 4th and 5th instars were 7, 7, 6, 6 and 6 days in G1, and 20, 20, 24, 72 and 33 days in G2, respectively. Temperature seems to greatly influence the duration of its life stages. A fungus (Paecilomyces tenuipes Samson), garden lizard Calotes versicolor (Daudin), and several bird species (Stachyris nigriceps Blyth, Spelaeornis caudatus (Blyth) and Dendrocitta frontalis Horsefield) were found effective in reducing the population of A. bipunctata.

Prey concealment and spatiotemporal patrolling behaviour of the Indian tree ant Oecophylla smaragdina (Fabricius)

Oecophylla smaragdina workers conceal prey with leaves and twigs on discovering large prey on their ground territory. The prey concealment behaviour occurs concurrently with prey capture and killing. Ants were observed conducting spatiotemporal patrolling around large prey. The garden lizard Calotes versicolor and at least two predatory ant species were found to forage in the same area as O. smaragdina. It is suggested that the prey concealment behaviour of Oecophylla may be a strategy to prevent prey detection by vertebrate predators which use vision to prey on similar large prey species.

Sex reversal by testosterone and not by estradiol or temperature in Calotes versicolor, the lizard lacking sex chromosomes

AbstractThe garden lizard Calotes versicolor lacks identifiable sex chromosomes. The present study demonstrates that temperature has no apparent effect on the determination of sex. In embryos reared at higher temperature (32°, 34°, 35°C), the gonads differentiate earlier than in controls and the overall duration of embryonic incubation is dramatically reduced. Exogenous administration of testosterone (100 μg/egg) to embryos of stages 28, 30, and 33 results in the majority of them developing into males; no female is encountered. Testosterone also accelerates the differentiation of testes. Estradiol (5, 10, μg/egg), administered at the same stages as testosterone, does not show any effects on gonadal differentiation. These results indicate that in C. versicolor, female is the default sex and the male is heterogametic. Apparently, this is the first report in a reptile in which testosterone has been shown to cause reversal into male sex. © 1995 Wiley‐Liss, Inc.

Effect of methylene blue and cobaltous chloride on the alloxan-induced changes in collagen characteristics in the skin of garden lizard Calotes versicolor

In the present study the effect of two chemicals such as methylene blue and CoCl 2 on the accelerated ageing of collagen in alloxan-diabetic lizards has been tested. Both methylene blue and CoCl 2 have been found to accelerate the ageing of collagen in normal lizards. While methylene blue enhanced the effects of alloxan in alloxanized lizards, CoCl 2 tended to reverse it. It appears that methylene blue acts as a potentiator of alloxan; CoCl 2, on the contrary, showed clear anti-ageing effects.

Seasonal and Sexual Differences in the Effects of Parathyroidectomy in the Indian Garden Lizard Calotes versicolor with a Note on Follicle Formation in Reptilian Parathyroids

AbstractMale and female C. versicolor were parathyroidectomized and/or administered with parathyroid extract during summer and winter. Sexual as well as seasonal differences were noticed in the effects. The results correlate with the often reported seasonal histophysiological changes in the parathyroids, suggesting "physiological parathyroidectomy" in winter lizards. Oestrogen induced hypercalcemiaappears to prevail in female lizards during the breeding season. Seasonal histological studies on the parathyroids ofthis lizard suggest that the often reported parathyroid follicles in reptiles originate due to degeneration of secretory parenchyma and that the follicular luminal content is only a condensate of the material released during degeneration. Though such follicle formation has also been reported in mammalian parathyroids, the causative factors seem to differ.

Age related changes in the Ca/P molar ratio in the bones of the garden lizard Calotes versicolor

There is a gradual shift of Ca/P molar ratio in the bones of the garden lizard Calotes versicolor till they weight about 29 g. At this stage, the Ca/P molar ratio seems to be as in apatite. In older animals the apatitic ratio is maintained with a range of variation from 10 5·1 to 10 6·5 . It is probable that the structure of collagen acting as template for calcification, is not deranged during this phase of life-span of the lizard.

Histochemical studies on the neurosecretory system of the common garden lizard Calotes versicolor (Daudin) under experimental condition

Histochemical localizations of various substances in the hypothalamic neuro-secretory cells as well as neurohypophysis of the normal and stressed (scalded) garden lizards, Calotes versicolor suggest that the neurosecretory materials, secreted by the hypothalamic neurones may be a mucoprotein-lipoprotein complex which is finally stored in the neuro-hypophysis. Only the proteinaceous fraction of this complex appears to be released by the nerve terminals in the neurohypophysis under the stressed condition. Such suggestion implies a chemical transformation of neurosecretory substances after leaving the neurosecretory cell body.

Pars intermedia of the pituitary gland and integumentary colour changes in the garden lizard Calotes versicolor

1. The effect of light and of colour of the background on the secretory activity of the pars intermedia of the garden lizard has been investigated. 2. Absence of light, as well as black illuminated background, produces increased acticity of the pars intermedia, proportional to the duration of the experiment. 3. Pale illuminated background has no effect on the secretory activity of the pars intermedia. 4. The hormone appears to be contained in an acidophilic colloid. 5. The pars intermedia is supplied by numerous branches from the marginal blood vessel. 6. The results have been discussed in the light of available information.