THE PHOTOPERIOD’S EFFECT ON LARVAE OF THE CAUCASIAN TOAD, BUFO VERRUCOSISSIMUS IN LABORATORY CONDITIONS 

Afrin Kirill Aleksandrovich, Postgraduate student, Russian State Agrarian University – Moscow Timiryazev Agricultural Academy (49 Timiryazevskaya street, Moscow, Russia), E-mail: afrin_ka@rambler.ru
Stepankova Irina Vladimirovna, Postgraduate student, Russian State Agrarian University – Moscow Timiryazev Agricultural Academy (49 Timiryazevskaya street, Moscow, Russia), E-mail: stepankova@rgau-msha.ru
Kidov Artem Aleksandrovich, Candidate of biological sciences, associate professor, sub-department of zoology, Russian State Agrarian University – Moscow Timiryazev Agricultural Academy (49 Timiryazevskaya street, Moscow, Russia), E-mail: kidov_a@mail.ru 

597.841:591.16 

DOI

10.21685/2307-9150-2020-3-7 

Background. The effect of the photoperiod on amphibian larvae remains poorly understood. Based on the results of previous studies, it can be noted that the effect of daylight hours differs significantly in amphibians in different taxonomic groups. The Caucasian toad, Bufo verrucosissimus, is common in the forest belt of the Caucasus and the Levant. The species is included in the Red Data Books of the Russian Federation, Azerbaijan and South Ossetia. The technology of zooculture of this species is currently being developed. The optimal conditions for growing the larvae of the Caucasian toad, including density and temperature, have been determined. The present study is devoted to the study of the effect of different daylight hours on the duration of development and survival of B. verrucosissimus larvae, the size of young toads after metamorphosis, and the cost of feed for their rearing. The purpose of this work is to identify the optimal light regime for growing the larvae of the Caucasian toad in zooculture.
Materials and methods. The material for the research was the offspring from the laboratory breeding of a pair of Caucasian toads caught in the Karachay-Cherkess Republic. The larvae were kept in containers 39 × 28 × 14 cm filled with 9 L of water. The containers (400 lux) were illuminated with fluorescent lamps located at a distance of 5 cm from the water surface. When keeping the larvae, five variants of the photoperiod were used: round-the-clock lighting, 18 hours a day, 12 hours a day, 6 hours a day, round-the-clock lack of lighting. Raising animals under each illumination mode was carried out in triplicate.
Results. The length of daylight hours influenced the duration of the larval development of the Caucasian toad. Larvae reared under 24-hour lighting had the longest development before metamorphosis. In other variants, the duration of larval development
was similar; however, the lowest values of this indicator were in the group with a photoperiod of 12 hours. The larvae demonstrated high survival under all illumination options; however, it was maximal in the complete absence of illumination, and minimal, with a photoperiod of 12 hours. The largest were toads raised under 24-hour lighting. All other groups did not differ in terms of size characteristics. The highest feed costs for growing one larva before metamorphosis were under 24-hour illumination, and the lowest – in the dark and under 6-hour illumination. The feed costs per animal were similar in other groups. For an increase in 1 g of toad weight after metamorphosis, most of all was spent on food in the group with a light period of 12 hours, and the least – with a photoperiod of 6 hours.
Conclusions. It is recommended to use 6-hour daylight hours for growing the larvae of the Caucasian toad in the laboratory. During this photoperiod, the larvae had a relatively short period of development (46–58 days), high survival rate (88,9–100 %), body length (10,0–12,4 mm) and weight (0,10–0,20 g ) after the passage of metamorphosis, as well as low feed costs for growing one individual (0,196–0,216 g). 

Key words

amphibians, rare species, conservation, larvae, daylight hours, zoo culture 

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1. Lobachev E. A. Vliyanie kolebaniy ekologicheskikh faktorov na embrional'no-lichinochnoe razvitie zemnovodnykh: avtoref. dis. kand. biol. nauk [Influence of fluctuations of ecological factors on embryonic-larval development of amphibians: author’s abstract of dissertation to apply for the degree of the candidate of biologocal sciences]. Saransk, 2008, 23 p. [In Russian]
2. Ruchin A. B. Pertanika Journal of Tropical Agricultural Science. 2018, vol. 41, no. 4, pp. 1889–1897.
3. Ruchin A. B. Periodico Tche Quimica. 2018, vol. 15, no. 30, pp. 152–159.
4. Lyapkov S. M., Severtsov A. S. Zoologicheskiy zhurnal [Zoological journal]. 1994, vol. 73, no. 1, p. 97. [In Russian]
5. Kidov A. A., Afrin K. A., Stepankova I. V., Gorikov A. A. Izvestiya Gorskogo gosudarstvennogo agrarnogo universiteta [Proceedings of Gorsky State Agrarian University]. 2020, no. 57 (1), pp. 164–169. [In Russian]
6. Nemyko E. A., Kidov A. A., Vyatkin Ya. A. Izvestiya vysshikh uchebnykh zavedeniy. Povolzhskiy region. Estestvennye nauki [University proceedings. Volga region. Natural sciences]. 2019, no. 1 (25), pp. 113–125. DOI 10.18500/1814-6090-2018-18-3-4-125-134. [In Russian]
7. Kidov A. A., Nemyko E. A. Aktual'nye problemy sokhraneniya bioraznoobraziya i ekologicheski sbalansirovannogo prirodopol'zovaniya na Zapadnom Kavkaze [Actual issues of biodiversity conservation and ecologically balanced nature management in the Western Caucasus]. Nalchik, 2019, pp. 76, 77. [In Russian]
8. Nemyko E. A., Vyatkin Ya. A., Kidov A. A. Sovremennaya gerpetologiya [Modern herpetology]. 2019, vol. 19, no. 2-3, pp. 125–131. DOI 10. 18500/1814-6090-2019-19-3-4-125-131. [In Russian]
9. Afrin K. A., Stepankova I. V., Kidov A. A. Izvestiya Gorskogo gosudarstvennogo agrarnogo universiteta [Proceedings of Gorsky State Agrarian University]. 2020, no. 57 (3), pp. 94–98. [In Russian]
10. Ruchin A. B. Biological Rhythm Research. 2019. DOI 10.1080/09291016.2019.15 94126.
11. Pyastolova O. A., Tarkhnishvili D. N. Ekologiya ontogeneza khvostatykh amfibiy i problema sosushchestvovaniya blizkikh vidov [Ecology of ontogeny of tailed amphibians and the problem of coexistence of closely related species]. Sverdlovsk: UrO AN SSSR, 1989, 156 p. [In Russian]
12. Khas Z. T., Vaissi S., Yaghobi S., Sharifi M. Zoology and Ecology. 2018. DOI 10.1080/21658005.2018.1517714.
13. Khas Z. T., Vaissi S., Yaghobi S., Sharifi M. Russian Journal of Ecology. 2019, vol. 50, no. 1, pp. 80–87.
14. Ruchin A. B. Biological Rhythm Research. 2019. DOI 10.1080/09291016.2019.16 31025.
15. Eichler V. B., Gray L. S. Development, Growth and Differentiation. 1976, vol. 18, pp. 177–182.
16. Gutierrez P., Delgado M. J., Alonso-Bedate M. Comparative Biochemistry and Physiology. 1984, vol. 79, pp. 255–260.
17. Edwards M. L., Pivorun E. B. General and Comparative Endocrinology. 1991, vol. 81, pp. 28–38.
18. Jablonski D., Sadek R. A. Herpetozoa [Herpetozoa journal]. 2019, vol. 32, pp. 255–258. DOI https://doi.org/10.3897/herpetozoa.32.e37560.
19. Özdemir N., Dursun C., Üzüm N., Kutrup B., Gül S. Amphibia-Reptilia. 2020, pp. 1–13. DOI 10.1163/15685381-bja10009.
20. Kuz'min S. L. Krasnaya kniga Rossiyskoy Federatsii (zhivotnye) [The Red Book of the Russian Federation (animals)]. Moscow: Astrel', 2001, pp. 318, 319. [In Russian]
21. Qəniyev F. R. Azərbaycan respublikasinin qirmizi kitabi. Nadir və nəsli kəsilməkdə olan fauna növləri [The Red Book of the Republic of Azerbaijan. Rare and endangered species]. 2nd ed. Baku, 2013, pp. 226, 227.
22. Tuniev B. S., Lotiev K. Yu. Krasnaya kniga Respubliki Yuzhnaya Osetiya [The Red Book of the South Ossetia]. Nalchik: Poligrafservis i T, 2017, pp. 219, 220. [In Russian]
23. Kidov A. A., Matushkina K. A., Afrin K. A., Blinova S. A., Timoshina A. L., Kovrina E. G. Sovremennaya gerpetologiya [Modern herpetology]. 2014, vol. 14, no. 1-2, pp. 19–26. [In Russian]
24. Matushkina K. A., Kidov A. A., Seryakova A. A. Izvestiya vysshikh uchebnykh zavedeniy. Povolzhskiy region. Estestvennye nauki [University proceedings. Volga region. Natural sciences]. 2020, no. 1 (29), pp. 36–45. DOI 10.21685/2307-9150-2020-1-4. [In Russian]