Iskenderov Tavakkyul' Mukhtar ogly, Candidate of biological sciences, associate professor, leading researcher, the terrestrial vertebrates laboratory, Institute of Zoology of the National Academy of Sciences of the Azerbaijan Republic (block 504, passage 1128, A. Abbaszadeh street, Baku, the Republic of Azerbaijan), E-mail: tavakkul@zoology/science.az
Background. In the autumn, the Transcaucasian Levantine viper sometimes mates for the second time, and in captivity, outside the breeding season, some females lay eggs with developed embryos. We discussed the possible causes and the adaptive value of these reproductive acts of the Transcaucasian Levantine viper.
Materials and methods. With the aim of studying the reproductive biology and breeding of the Transcaucasian viper in captivity in the late fall 1983–2014 years in arid areas of Gobustan and Apsheron peninsula had been captured 57 individuals females. Females caught in late autumn were kept in favorable temperature conditions (29–31 °C).
Results. During the study period (1983–2014) in winter 10 out of 57 females (17,5 %) laid 67 eggs with developed embryos inside. The number of eggs in the nests ranged from 3 to 8. Thus, the repeated mating and a favourable conditions of keeping of females in captivity contributed to the off-season laying eggs. In nature, repeated mating of a Levantine viper was repeatedly observed by us and indicated in the literature. Repeated mating, apparently, provides females with sperm material, which is stored in female oviducts for the delivery of new generations in the next season without the participation of males. It is indicated that as result of placing the females in favorable conditions, the maturation of oocytes is likely to accelerate and the fertilization of the spermatozoa re-mating occurs and the process ends with the laying of eggs out of season. Secondly, it is possible that there were fertilized eggs in the oviduct of the female from the autumn. However, due to the absence of favorable temperature conditions in the external environment, these eggs passed into the state of embryonic diapause. By placing the females in favorable conditions, embryonic development is restored and the further formation of eggs takes place, and they are deposited outside the reproduction season.
Conclusions. Thus, for the first time, it is suggested that there is an embryonic diapause in the viper. The facts of off-season egg laying and the reproductive features that contribute to this are of practical importance and can be used to solve the breeding of egg-laying reptiles. The results of the study can be used to solve the problem of breeding egg-laying reptile species in captivity.
1. Shmal'gauzen I. I. Problemy Darvinizma [Problems of Darwinism]. Leningrad: Nauka, 1969, pp. 379–426. [In Russian]
2. Sharifov F. K. Yadovitye zhivotnye Sredney Azii i ikh yady: sb. materialov Sredneaziatskoy konf. AN Uzbekskoy SSR [Poisonous animals of Central Asia and their poisons: proceedings of a Central Asian conference of the Uzbek SSR Academy of Sciences]. Tashkent, 1970, pp. 88–90. [In Russian]
3. Aliev T. R. Yadovitye zmei Azerbaydzhana (ekologo-faunisticheskie issledovaniya): avtoref. dis. kand. biol. nauk [Poisonous snakes of Azerbaijan (ecological faunistic studies): author’s abstract of dissertation to apply for the degree of the candidate of biological sciences]. Baku, 1974, 21 p. [In Russian]
4. Nadzhafov Dzh. A., Iskenderov T. M. Zoologicheskiy zhurnal [Zoological journal]. 1994, vol. 73, iss. 6, pp. 79–84. [In Russian]
5. Bogdanov O. P., Sharifov F. G. Gerpetologiya: mezhvuz. sb. nauch. tr. [Herpetology: interuniversity proceedings]. Krasnodar, 1979, pp. 100–123. [In Russian]
6. Iskenderov T. M. Materialy nauchnoy konferentsii [Proceedings of a scientific conference]. Baku: BGU, 2001, pp. 113–114. [In Russian]
7. Bakiev A. G. Voprosy gerpetologii: materialy III s"ezda Gerpetologicheskogo obshchestva im. A. M. Nikol'skogo [Issues of herpetology: proceedings of III congress of the Nikolsky Herpetological Society]. Saint-Petersburg, 2008, pp. 31–34. [In Russian]
8. Iskenderov T. M. Morfologicheskaya izmenchivost' v rannem embriogeneze nekotorykh vidov reptiliy i ee adaptivnoe znachenie: avtoref. dis. kand. biol. nauk [Morphological variability at the early embryogenesis of certain species of reptiles and its adaptive improtance: author’s abstract of dissertation to apply for the degree of the candidate of biological sciences]. Moscow, 1978, 21 p. [In Russian]
9. Tuniev B. S. Voprosy gerpetologii: materialy III s"ezda Gerpetologicheskogo obshchestva im. A. M. Nikol'skogo [Issues of herpetology: proceedings of III congress of the Nikolsky Herpetological Society]. Saint-Petersburg, 2008, pp. 401–408. [In Russian]
10. Gao Jian-Fang, Qu Yan-Fu, Luo Lai-Gao. Zoological science. 2010, vol. 27, iss. 3, pp. 248–255.
11. Maksudov G. Yu. Dlitel'noe perezhivanie spermatozoidov v polovykh putyakh samok pozvonochnykh: avtoref. dis. kand. biol. nauk [Long-term survival of spermatozoa in female gential tracts of vertebrates: author’s abstract of dissertation to apply for the degree of the candidate of biological sciences]. Moscow, 1996, 26 p. [In Russian]
12. Holt W. V. Reproduction in domestic animals. 2011, vol. 46, append. 2, Special issue: SI, pp. 68–74.
13. Barros V. A., Rojas C. A., Almeida-Santos S. M. Herpetological journal. 2017, vol. 27, iss. 1, pp. 115–119.
14. Fordham D., Georges A., Corey B. Issue Functional ecology. 2006, vol. 20, iss. 4, pp. 670–677.
15. Rafferty A. R., Evans R. G., Scheelings T. F., Reina R. D. The American Naturalist. 2013, vol. 181, no. 2, pp. 245–253.
16. Rafferty A. R., Reina R. D. Proceedings of the Royal Society B: Biological Sciences. 2012, vol. 279, pp. 2299–2308.