Seasonally adaptable species may face greatest risk from climate change

March 8, 2018, Wageningen University
Credit: Wageningen University

A species of butterfly that changes its appearance through the seasons lacks the genetic variation needed to quickly evolve a different response to more unpredictable environmental conditions, such as those expected under a changing climate, according to an international study including researchers from Wageningen University & Research.

The study, published 8 March 2018 in Nature Communications, uses and genomic analysis of an African savannah butterfly, Bicyclus anynana, to suggest that that have different traits depending on the time of year may be especially vulnerable if the climate changes and their seasonal cues are no longer reliable.

Phenotypic plasticity and adaptation

"A general assumption in evolutionary biology is that species where individuals have the ability to adjust how they look and spend their energy in response to short-term changes in their environment, are also those most likely to adapt to . Such environmentally induced changes in the appearance and functioning of individuals, known as , are a common adaptation of insects in seasonally variable environments," said the study's lead author, Dr. Vicencio Oostra (University College London UCL Genetics, Evolution & Environment; Wageningen University & Research, Laboratory of Genetics).

"But there are theoretical predictions that this plasticity could be a hindrance to climate change adaptation, and we are now providing the first empirical support to those predictions that species specialised to changing seasons could face greater extinction risk due to climate change," he said.

Gene expression in a butterfly as an example

The researchers studied the butterfly Bicyclus anynana from Malawi which is a textbook example of seasonal plasticity. If an individual is born in the warm wet , it will live a short life of fast growth and maximal reproduction; if born in the cool dry season, its life history is one of inactivity, postponed reproduction, and long lifespan.

The authors analysed the RNA of 72 butterflies, in a split-brood, full factorial analysis investigating heritable and environmental effects, and found pervasive differences in how their are expressed between the dry and wet seasons. Within the abdomen and the thorax, close to half of their genes showed significant differences in how they are expressed between the two seasons. In addition, butterflies exhibited significant differences between families in the expression of many genes.

In contrast, they found that within the population, there was very little for the seasonal plasticity itself, as only 1% of genes were dependent on the interaction between genetic background (family) and season. While there was lots of heritable variation in gene expression, this almost entirely disappears when the researchers looked at the genes involved in how individuals reacted to seasonal change – in terms of seasonal adaptation, every butterfly does the same thing.

"These butterflies have adapted to respond to very specific environmental cues on the savannah, mainly temperature during development, that highly accurately predict each season. Any deviation in how they change their phenotype to tune it to the prevailing season is maladaptive. Therefore, it appears that what we see in the genetic variation for the plasticity genes is a very strong legacy of natural selection against deviations from these seasonal responses," said co-author Professor Bas Zwaan (Wageningen University & Research, Laboratory of Genetics).

"If their environment changes only very slowly, then this species could gradually adapt as potential beneficial mutations may come along, but in a rapidly changing climate, this is likely to be a problem. Seasonal changes are becoming less reliable, so being stuck in a specific seasonal response could put this species at risk of extinction," said co-author Dr. Christopher Wheat (Stockholm University).

While the researchers only looked at one particular species, they are planning to compare this butterfly to other species that live in less predictable environments to see if others might have more genetic variation that could help them adapt to climate change.

Potential consequences for biodiversity

"To gauge how climate change will affect biodiversity, it is crucial to identify which species are most at risk and which can adapt. There are many species with seasonal plasticity, so we suspect there could be numerous species like this that are more vulnerable to change than previously believed," added co-author Dr. Marjo Saastamoinen (University of Helsinki).

Thus, on the one hand the study indicates that there is genetic variation for phenotypic plasticity that can be exploited in nature for adaptation, and potentially also in an agricultural setting. On the other hand, the result of such adaptation is a depletion of variation and an increased vulnerability to rapid environmental change.

Explore further: Butterflies' wing patterns change with the seasons

More information: Vicencio Oostra et al. Strong phenotypic plasticity limits potential for evolutionary responses to climate change, Nature Communications (2018). DOI: 10.1038/s41467-018-03384-9

Related Stories

Butterflies' wing patterns change with the seasons

July 7, 2016

Tropical butterflies adapt to their environment to improve their chances of survival. The changes are triggered by hormone signals that transmit information about temperature to the butterflies' tissues. Biologist Ana Rita ...

How bird genetics adapt to climate change

January 5, 2018

As Earth's climate changes, species must adapt, shift their geographical ranges or face decline and, in some cases, extinction. Using genetics, UCLA biologists involved in the Bird Genoscape Project are racing against time ...

Birds outpace climate change to avoid extinction

July 9, 2013

A new study has shed light on the potential of birds to survive in the face of climate change. In the analysis, based on more than fifty years' detailed study of a population of great tits near Oxford, UK, a team of scientists ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

EPA adviser is promoting harmful ideas, scientists say

March 22, 2019

The Trump administration's reliance on industry-funded environmental specialists is again coming under fire, this time by researchers who say that Louis Anthony "Tony" Cox Jr., who leads a key Environmental Protection Agency ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.