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Breeding male of Rana arvalis from the study area.
Photo Credit: Germán Orizaola.
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Gobal warming is altering the reproduction of plants and animals,
notably accelerating the date when reproduction and other life processes occur.
A study by the University of Uppsala (Sweden), including the participation of
Spanish researcher Germán Orizaola, has discovered that some amphibians are
capable of making their offspring grow at a faster rate if they have been born
later due to the climate.
Over recent decades many organisms, both plants and animals, have
experienced a notable advance in the date when many of their life processes
(like reproduction, migration or flowering) occur, attributed to the impact of
climate change. An article published in the journal Ecology examines
the effects that these changes in the reproduction date have on the life cycles
of the amphibians.
"We specifically examined whether changes in the reproduction date
of a common amphibian species in the north of Europe, Rana arvalis, can
condition the growth and development of their offspring," the Spanish
researcher Germán Orizaola, from the University of Uppsala (Sweden) and
co-author of the study, said.
Results revealed that female frogs have the ability to influence both
the growth rate and the development of their offspring, and they adjust it
depending on the date of reproduction.
According to Orizaola, "the mechanism by which the female frogs
can condition the growth of their larvae could be due to the genes associated
with the maintenance of their biological clock being transferred to the embryos
and becoming active even before fertilization. This would provide the larvae
with the exact information regarding the progression of the growing
season."
One of the characteristics associated with climate change is an
increase in the inter-annual variability of climatic conditions, so organisms
are also exposed to greater uncertainty when it comes to determining the right
time to reproduce. This explains why the existence of mechanisms adjusting
growth and development rates depending on the variation in the start of
breeding is highly advantageous for many species.
In particular, as part of this study they observed that by delaying the
date of reproduction (which simulated a time of environmental instability), the
result was an equivalent reduction in the growth period for the larvae.
"That means the later this species of frog breeds, the faster the larvae
develop," explains the scientist.
An interesting aspect of the study is that the acceleration in growth
is produced under constant lab conditions. "The larvae were not exposed to
any outside sign that would indicate the progression of the growing
season," adds Orizaola.
"This result is very novel and demonstrates that the acceleration
in the development of the larvae is conditioned by the breeding females, which
reveals the existence of a 'transgenerational effect' in which the breeding
adults are capable of altering key aspects of the life cycle for the following
generations, to better prepare them to survive the environmental conditions
that they are going to experience," concludes the expert.
Citation
Richter-Boix A, Orizaola G, Laurila A. 2014 Transgenerational
phenotypic plasticity links breeding phenology with offspring life-history.
Ecology, 2014; 95 (10): 2715 DOI:
10.1890/13-1996.1