Incubation Temperature and Yolk Steroids Regulate Hatching Synchrony in Calotes versicolor (Daud.)

V. Vani, Gopal M. Advi Rao, Laxmi S. Inamdar (Doddamani)

Abstract


The chronology of hatching behavior, hatching success and the significance of maternal yolk steroids (estradiol and testosterone) in hatching synchrony were studied in the lizard Calotes versicolor at male-producing (25.5 ± 0.5 and 34 ± 0.5°C), female-producing (23.5 ± 0.5 and 31.5 ± 0.5°C) and at high (35°C) temperatures. The results reveal that in a given clutch, the embryo that has utilized most of its yolk initiates the pipping behavior first. Hatching success as well as incubation period decreases with increase in incubation temperature and the temperatures from 23.5 ± 0.5°C to 31.5 ± 0.5°C are recorded as optimum viable range for the development and successful hatching of C. versicolor eggs. Hatching is highly synchronous in C. versicolor irrespective of incubating temperature, sex and clutch-to-clutch differences. Significance of maternal steroids in hatching pattern was studied at both male and female-producing temperatures. High interclutch variance, but low intraclutch variance in estradiol and testosterone concentrations found at oviposition as well as at hatching suggest their possible role in the synchronization of hatching by exhibiting similar magnitude of steroid profile within a clutch. It is observed that there is no sex based hatching synchrony in this species. The study indicates that temperature and steroids act synergistically and might play a role in synchronization of hatching in C. versicolor.

Keywords


incubation temperature; hatching behavior; hatching synchrony; estradiol; testosterone

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References


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DOI: http://dx.doi.org/10.30906/1026-2296-2019-17-%25s-207-213

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