Damselflies dismiss distress

Damselflies in Sweden are evolving rapidly to adapt to changing climatic conditions, and, far from being knocked about by rising temperatures, they are expanding their range.

Research published in the journal Molecular Ecology reveals details of multiple genetic changes in the species (Ischnura elegans), including genes associated with tolerance to heat shock and salinity, as well as mate selection. 

The scientists, led by Rachael Dudaniec of Australia’s Macquarie University, identify environmental thresholds beyond which climate strongly influences natural selection for damselflies. They conclude that the evidence shows that the species is “rapidly adapting” to changing climate as it pushes northwards, expanding its range.

“Damselflies, like other aquatic insects, are faced with a dilemma, given the current and unprecedented rate of global warming,” says Dudaniec.{%recommended 5035%}

“Either they perish, move elsewhere or adapt to the new environmental conditions. It’s a classic case of fight or flight.”

To make their findings, Dudaniec and colleagues captured 426 insects from 25 sites across the damselfly range in Sweden. They then sequenced the insects’ genomes and analysed 13,612 instances where small differences – known as single nucleotide polymorphisms (SNPs) – were apparent between individuals.

They found that these gene variants, conditioning the insect to better tolerate specific stresses, changed according to location with the range.

“We examined the degree of turnover from one variant of a gene to another variant,” says Dudaniec. 

“For example, how strongly does one variant of a gene change to another variant as you move to higher latitudes. These patterns show us how natural selection acts upon the damselfly.

“Genes that are more favourable in the new environments become more common, so that the damselfly is better adapted to its surroundings.”

The scientists concluded that the damselfly possesses a wealth of evolutionary strategies to cope with changing conditions – a genetic toolbox that sets the species up well for survival.

Some other species, they add, might not be so fortunate.

“Our research highlights the need to further investigate how different species will cope with climate change,” says Dudaniec.

“Identifying the species that are going to struggle the most in changing environments will allow us to direct conservation actions more appropriately.”