Phenotypic plasticity of the yellow-bellied toad (Bombina variegata) under habitat drying conditions

[A. Radmilović]

119 str.

Biologija - Zoologija / Biology - Zoology

Ekološki uslovi u prirodi su promenljivi, pa organizmi moraju biti sposobni da se prilagode tim promenama kako bi opstali. Sposobnost jednog genotipa da u odgovoru na promene sredine modifikuje razviće, osobine životne istorije, morfologiju i ponašanje naziva se fenotipska plastičnost. Isušivanje staništa predstavlja jedan od najsnažnijih abiotičkih stresora koji remeti životni ciklus vodozemaca. Mnoge vrste bezrepih vodozemaca imaju sposobnost da ubrzaju razviće i završe metamorfozu pre nego što stanište presuši. U ovoj disertaciji ispitali smo kako isušujući uslovi staništa utiču na osobine životne istorije, morfologiju i fiziologiju žutotrbog mukača (Bombina variegata). Rezultati su pokazali da ispitana populacija nema sposobnost da ubrza razviće u isušujućim uslovima. Naprotiv, larvalni period je bio produžen ili nepromenjen, nezavisno od stadijuma razvića u kom su jedinke bile izložene isušivanju. Isušujući uslovi su negativno uticali na dužinu tela i masu jedinki, što se negativno odrazilo na stopu rasta i kondicioni indeks, na početku (GS 42) i na kraju metamorfoze (GS 46). Međutim, to se nije odrazilo na dužinu i oblik repa niti na skakačke performanse juvenilnih jedinki. Takođe, nisu zabeležene promene u nivou kortikosterona ni u parametrima antioksidacionog sistema. Nepromenjen ili produžen larvalni period u uslovima isušivanja, uz stabilne fiziološke parametre, ukazuju na moguću modifikaciju HPI ose kod ove populacije. Ovi rezultati sugerišu da je populacija žutotrbog mukača sa ispitivanog lokaliteta lokalno adaptirana na specifične hidrološke uslove putem genetičke asimilacije.

Environmental conditions in nature are constantly changing, requiring organisms to adjust in order to survive. The ability of a single genotype to alter its development, life-history traits, morphology, and behavior in response to environmental variation is known as phenotypic plasticity. Habitat desiccation is one of the most severe abiotic stressors that disrupts the life cycle of amphibians. Many species of anurans can accelerate their development and complete metamorphosis before their aquatic habitats dry out. In this dissertation, we investigated how desiccation conditions affect life-history traits, morphology, and physiology in the yellow-bellied toad (Bombina variegata). Our results show that the studied population lacks the ability to accelerate development under desiccation stress. On the contrary, the larval period was either prolonged or unchanged, regardless of the developmental stage at which individuals were exposed to drying conditions. Desiccation negatively affected body length and mass, leading to a reduced growth rate and lower condition index at both the beginning (GS 42) and the end of metamorphosis (GS 46). However, these unfavorable conditions did not affect tail length or shape, nor did they impair the jumping performance of juvenile individuals. Additionally, no changes were observed in corticosterone levels or in parameters of the antioxidant system. The absence of developmental acceleration, along with stable physiological responses under desiccation stress, suggests a possible modification of the HPI axis in this population. These findings indicate that the B. variegata population from the studied locality may be locally adapted to specific hydrological conditions through genetic assimilation.

fenotipska plastičnost, žutotrbi mukač, isušivanje staništa, osobine životne isto rije, morfologija, fiziologija

phenotypic plasticity, yellow bellied toad, habitat desiccation, life history traits, morphology, physiology

591.5:597.825(043.3)

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