Developmental responses to UV‐B radiation in common frogRana temporariaembryos from along an altitudinal gradient

Abstract

Solar ultraviolet radiation (UV) is harmful for developing amphibians. As UV increases with altitude and latitude, it is suggested that high altitude and latitude populations have evolved tolerance to high levels of UV.Using laboratory experiments, we tested the hypothesis that Rana temporaria populations from several altitudes (438-2,450 m above sea level) were adapted to UV by assessing the effects of artificial UV on embryos mortality rate, malformations, and body length at hatching. We also tested the protective role of the jelly surrounding the embryos. Without artificial UV exposure, hatching success decreased with altitude of the population. Malformation rates were low for all populations (mean 1.36%), and hatching size increased with altitude. The artificial UV (UV-B, UV-A, and visible) used was similar to the solar spectrum received at high altitude. Exposed embryos had performance similar to that of embryos without exposure: a decreased hatching success with altitude and a low malformation rate (mean 0.85%). However, hatching size did not vary with altitude, and UV-exposed embryos tended to be smaller at hatching than non-exposed embryos. Removal of the protective jelly envelope greatly decreased the performance of UVexposed embryos: hatching success strongly decreased with altitude and embryos of the highest population (2,450 m asl) did not develop. Malformation reached 4.98%, without population differences, and hatching size of embryos without jelly was smaller than hatching size of non-manipulated embryos with no population effect. This study demonstrates that lowland jellyless embryos were less sensitive (i.e., exhibited a higher survival rate) than highland embryos and, on the other hand, that the jelly envelope was a more efficient protection for embryos in highland than in lowland populations. A trade-off hypothesis is presented to explain this difference in UV tolerance and protection among populations: in a harsh, highland environment (i.e., with a curtailed activity period), embryos have to invest in development and growth and, thus, embryo protection should be a female investment (via the jelly). In a lowland environment, embryonic growth and development are less constrained and embryos are able to invest and use protection or repair mechanisms inherited from their parents.

Are glacial refugia hotspots of speciation and cytonuclear discordances? Answers from the genomic phylogeography of Spanish common frogs

“…The same rationale applies when interpreting biological results from model organisms under a phylogeographic framework. Because of its abundance and broad ecological niche, its wide geographic and altitudinal distribution, as well as its high genomic and phenotypic plasticity, the common frog has been a model system to address fundamental topics in ecological, evolutionary, and conservation sciences, e.g., local adaptation (e.g., Muir, Biek, Thomas, & Mable, ), dispersal (e.g., Dolmen & Seland, ; Palo et al, ), epidemiology (e.g., Duffus, Garner, Nichols, Standridge, & Earl, ), resistance to abiotic stresses (e.g., Marquis, Miaud, & Lena, ), sex determination mechanisms (e.g., Rodrigues, Vuille, Brelsford, Merilä, & Perrin, ), or sex‐chromosome evolution (e.g., Rodrigues, Studer, Dufresnes, & Perrin, ). The present survey thus provides the necessary context to carry out more comprehensive studies on Iberian common frogs, where the overlooked diversity offers a promising playground for future research.…”

Molecular Response to Ultraviolet Radiation Exposure in Fish Embryos: Implications for Survival and Morphological Development

“…Ultraviolet radiation is widely mentioned as a damaging environmental factor for organisms in both terrestrial and aquatic systems (33,34). The effects derived from a deleterious UV exposure are known to cause irreparable effects at different levels from organism survival and reproduction (8–11) to cellular metabolism and viability (13,14). However, the molecular responses triggered in an animal organism after a UV exposure are not yet understood.…”

“…The significant level was P < 0.05. UV exposure are known to cause irreparable effects at different levels from organism survival and reproduction (8)(9)(10)(11) to cellular metabolism and viability (13,14). However, the molecular responses triggered in an animal organism after a UV exposure are not yet understood.…”

Drivers of amphibian declines: effects of ultraviolet radiation and interactions with other environmental factors

“…Perotti and Diéguez [92] also found that the optical properties of the egg jelly envelope surrounding the embryo is also correlated with embryonic melanin concentration: the egg jelly of the species with the lowest embryonic melanin concentration (P. thaul) had the highest UVR absorbance whereas the egg jelly of the species with the highest embryonic melanin concentration (R. spinulosa) had the lowest UVR absorbance. Several additional studies have similarly shown that the UVR absorbance by the egg jelly envelope varies with wavelength and among species [93][94][95][96][97], and also the protective role of the jelly envelope varies among populations within a species along an elevation gradient [98]. Such research indicates that for some species the jelly envelope may provide adequate protection against UVR for the embryo, whereas others may rely on alternative defence strategies such as pigmentation, behavioural avoidance (e.g.…”