Demography of fan-throated lizard, Sitana ponticeriana (Cuvier) in a cotton field in Dharwad district of Karnataka state, India

The demographic studies on Sitana ponticeriana show that the species is abundant in Gabbur village. The lizards exhibited a diurnal variation in their activity pattern (basking, foraging, seeking refuge, etc.). They were active in the morning hours when air temperature was ≤ 33° C and census yielded maximum numbers (45 ± 2.19 in 18,748 sq m or ~ 1.9 ha area). The study provides a pilot index as well as a reliable and accurate methodology for population survey of the lizard. The pilot index is essential for any large scale monitoring project and population trend analysis in future

Does temporal variation in predation risk affect antipredator responses of larval Indian Skipper Frogs (Euphlyctis cyanophlyctis)?

Predation risk varies on a moment-to-moment basis, through day and night, lunar and seasonal cycles, and over evolutionary time. Hence, it is adaptive for prey animals to exhibit environment-specific behaviour, morphology, and (or) life-history traits. Herein, the effects of temporally varying predation risk on growth, behaviour, morphology, and life-history traits of larval Indian Skipper Frogs (Euphlyctis cyanophlyctis (Schneider, 1799)) were studied by exposing them to no risk, continuous, predictable, and unpredictable risks at different time points. Our results show that larval E. cyanophlyctis could learn the temporal pattern of risk leading to weaker behavioural responses under predictable risk and stronger responses to unpredictable risk. Temporally varying predation risk had a significant impact on tadpole morphology. Tadpoles facing continuous risk had narrow tail muscles. Tadpoles facing predictable risk during the day were heavy with wide and deep tail muscles, whereas those facing predictable risk at night had long tails. Tadpoles facing unpredictable risk were heavy with narrow tail muscles. Metamorphic traits of E. cyanophlyctis were also affected by the temporal variation in predation risk. Tadpoles facing predictable risk during the day emerged at the largest size. However, tadpoles facing predictable risk at night and unpredictable risk metamorphosed earlier, whereas those facing continuous risk metamorphosed later.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Sexual dimorphism in baseline urinary corticosterone metabolites and their association with body-condition indices in a peri-urban population of the common Asian toad (Duttaphrynus melanostictus)

Field endocrinology research through the quantification of glucocorticoids or stress hormones in free-living wildlife is crucial for assessing their physiological responses towards pervasive environmental changes. Urinary corticosterone metabolite (UCM) enzyme-immunoassay (EIA) has been validated for numerous amphibian species as a non-invasive measure of physiological stress. Body-condition indices (BCIs) have also been widely used in amphibians as an indirect measure of animal health. Field endocrinology research on amphibian species in Asia is limited. In this study, we validated a UCM EIA in a peri-urban sub-population of the common Asian toad (Duttaphrynus melanostictus) in Pune, Maharashtra, India. We determined the baseline levels of UCMs in male (n. = 39) and female (n. = 19) toads. Secondly, we used a standard capture handling protocol to quantify changes in UCMs during short-term captivity. We also determined BCIs in the male and female toads using Fulton's index (K) and residual condition index (RCI). The results showed that mean baseline levels of UCMs were significantly higher in male toads than in females. There was no significant change in mean levels of UCMs of males and females between capture and captivity (0-12. h). This highlights plausible habituation of the species to the peri-urban environment. Associations between UCMs with BCIs (K and R) were positive in male toads but negative in females. In conclusion, our UCMs EIA can be applied with BCIs to assess health of the Asian toads. We also suggest that direct fitness parameters such as sperm and oocyte quality, reproductive ecology and immunocompetence measurements should be applied in combination with these conservation physiology tools to quantify the fitness consequences of pervasive environmental changes on native amphibians

Urinary corticosterone metabolite responses to capture and visual elastomer tagging in the Asian toad (Duttaphrynus melanostictus)

Herpetological research involving amphibians is increasingly using mark and recapture methods, employing various techniques such as toe-clipping and visible implant alphanumeric tags. Visual Implant Elastomer (VIE) is a new method available for herpetological surveys, involving a coloured dye inserted into the epidermal skin surface of frogs. Previously, there has been only one study which demonstrated that the VIE method does not generate a significant physiological stress response (using a faecal glucocorticoid method) in a captive amphibian species. Physiological stress can also be quantified non-invasively using urinary corticosterone metabolite (UCM) enzyme-immunoassay in amphibians. In this study, we tested the physiological stress response of a common amphibian species, wild caught Asian toads (Duttaphrynus melanostictus), by comparing UCM responses to capture handling, sham control or VIE marking method. Adult males (n = 38) were captured and sampled for baseline UCM (t = 0 h) then marked either using the VIE or sham (saline control), or only handled during capture. Subsequently, urine samples were collected at t = 2, 12 and 24 h for toads within each group. UCM levels were quantified using an enzyme-immunoassay (EIA) to determine differences among treatment groups and over time following capture. Toads generated acute stress responses to all three groups, showing a change in UCMs between baseline samples, 12 h, and 24 h samples. The mean UCM levels were not significantly different between the VIE method and the control groups (capture handling or sham operated). These results indicate that VIE method of tagging is no more stressful than routine handling of amphibians, hence in this context, the method does not have any additional welfare implications. Future research should explore the limitations of VIE tagging for long-term mark recapture studies, however, our current findings support its application as a minimally-invasive method for marking amphibians

Annual changes in corticosterone and its response to handling, tagging and short-term captivity in Nyctibatrachus humayuni

Glucocorticoids (GCs) are primarily involved in mobilising energy reserves to various physiological processes including reproduction. During situations of stress, GCs also help in coping with stress by diverting energy away from processes such as growth and reproduction. Hence, studying annual and seasonal changes in GCs of wild populations can help in understanding their role in stress management and reproduction. The quantification of GCs in wild animals involves capturing, handling and restraining, which could be stressful. Moreover, different species may exhibit differential sensitivity to different stressors. Hence, determining species-specific sensitivities and responses to different stressors may help in developing effective conservation measures. In this context, we studied the annual and seasonal variations in corticosterone metabolites of the Bombay night frog, Nyctibatrachus humayuni. In addition, the effects of handling, marking and short-term captivity (24 h) on corticosterone metabolite levels of N. humayuni were determined. Our results show that urinary corticosterone metabolites (UCM) varied significantly annually and between the sexes; in males, the levels were highest during the breeding season, whilst in females, the levels were highest just before the breeding season. Interestingly, UCM levels of both the sexes were not affected by tagging with visual implant elastomer (VIE), and by short-term captivity, suggesting that these manipulations were not stressful in terms of corticosterone responses

Growth, sexual maturation and body size dimorphism in the Indian bullfrog, Hoplobatrachus tigerinus (DAUD)

The pattern of growth, age and size at sexual maturity, and sexual size dimorphism were determined for 30 Indian bullfrogs, (Hoplobatrachus tigerinus) reared in out-door terraria, from metamorphosis to 3 years of age. Size and the growth rates for males and females were comparable throughout the study. For SVL, annual mean growth rate was very high in the first year (7.31 cm) but declined in the 2<SUP>nd</SUP> (2.70 cm) and 3<SUP>rd</SUP> (0.53 cm) years. For body mass, annual mean growth rate was similar (∼68 g) for the 1<SUP>st</SUP> and 2<SUP>nd</SUP> years but declined (24.31 g) in the 3<SUP>rd</SUP> year. In general, growth was faster during summer than in winter months. After attaining maturity, growth rate declined for both sexes. Some males attained sexual maturity in the first year (10 months old), while the remaining males and all females matured at the end of 2<SUP>nd</SUP> year. In naturally occurring breeding populations, males tend to be smaller than females. This difference appears to be due to the presence of males and females of different age groups rather than differences in early growth rates

Interrelationship among steroid hormones, energetics and vocalisation in the Bombay night frog (Nyctibatrachus humayuni)

In vertebrates, the increase in plasma androgens and corticosteroids is essential for the expression of reproductive behaviour. In male anurans, the interaction between hypothalamus-pituitary-gonadal and hypothalamus-pituitary-interrenal axes plays a pivotal role in calling behaviour and energy mobilisation through the secretion of testosterone and corticosterone respectively. To explain the association among body condition, testosterone, corticosterone and calling behaviour the energetic-hormone-vocalisation (EHV) model has been proposed. The model predicts that with continued participation in chorus activity within and across nights, levels of circulating androgens, corticosterone and vocal effort tend to increase and should be positively correlated in calling males. Consequently, decreasing energy reserves should be inversely correlated with corticosterone level in calling males. Depleted energy reserves lead to the peaking of circulating corticosterone, which suppresses androgen production and calling behaviour. In the present study, we used . Nyctibatrachus humayuni with unique reproductive behaviour to test the model by quantifying calling behaviour and urinary metabolites of testosterone and corticosterone. We also computed the body condition index (BCI) to assess the association among energetics, levels of testosterone, corticosterone and calling behaviour. The results show that calling males had higher levels of urinary testosterone metabolites (UTM) than non-calling males indicating the importance of testosterone in controlling the calling behaviour. Surprisingly, urinary corticosterone metabolite (UCM) levels were comparable between calling and non-calling males. Further, calling males had higher body condition estimates than non-calling males. The vocal effort was neither associated with UTM, UCM nor BCI. However, a positive association was observed between UTM and UCM levels in calling males indicating the requirement of higher energy for advertisement. Analysis of UTM and UCM levels throughout the breeding season revealed that breeding basal of UTM was significantly higher than that of UCM. Interestingly, UCM levels were maintained at a lower threshold during the breeding season. These observations are in line with some of the predictions of EHV model

Relative Influence of kinship and density on metamorphic traits of Tomopterna breviceps

Tadpoles of Tomopterna breviceps from five different sibships were subjected to pure (siblings) or mixed (kin and nonkin) rearing conditions at varying densities to determine relative influence of kinship and density on metamorphic traits of larval growth, larval period, and size at metamorphosis. Individual rearing of 50 tadpoles from five different parental lines revealed no significant difference in any metamorphic traits among sibships. At a given density, metamorphic traits were comparable between sibling and mixed groups indicating an absence of kinship influence. However, progressive increase in the number of tadpoles (density) affected severely the metamorphic traits regardless of the kinship/mixed rearing conditions. This resulted in an increase in larval period, decrease in the size of metamorphs in comparison to those reared at a lower density or uncrowded conditions. Our study shows that in T. breviceps density of rearing rather than kinship plays a major role in affecting the metamorphic traits

Kin recognition in Bufo scaber tadpoles: ontogenetic changes and mechanism

Ontogenetic changes in kin-recognition behavior, effect of social environment on kin-recognition ability, and use of visual and chemical cues in kin recognition have been studied in tadpoles of Bufo scaber after rearing them with kin, in mixed groups, or in isolation from Gosner stage 12 (gastrula). By use of a rectangular choice tank the tadpoles were tested for their ability to choose between (a) familiar siblings and unfamiliar non-siblings, (b) unfamiliar siblings and familiar non-siblings, and (c) unfamiliar siblings and unfamiliar non-siblings. When tested without any stimulus groups in the end compartments of the tank, random distribution was observed for the tadpoles and no bias for the apparatus or the procedure. In the presence of kin and non-kin in the end compartments, significantly more tadpoles spent most of their time near kin (familiar or unfamiliar) rather than near non-kin during early larval stages, up to stage 37. After stage 37 (characterized by the differentiation of toes), test tadpoles showed no preference to associate with kin, suggesting an ontogenetic shift in the kin-recognition ability in B. scaber. In experiments involving selective blockade of visual or chemical cues the test tadpoles preferentially associated near their kin on the basis of chemical rather than visual cues. These findings suggest that familiarity with siblings is not necessary for kin recognition and that kin-recognition ability is not modified after exposure to non-kin by mixed rearing. The findings for B. scaber indicate a self referent phenotype matching mechanism of kin recognition which is predominantly aided by chemical rather than visual cues