If the answers to the first two questions come back negative, a backup plan has already been floated. Hoverflies taken from larger populations abroad – for example in Sweden or Finland – could be brought in to kickstart a British recovery. But such reintroductions are tricky. “Understanding how genetically differentiated they are would be really helpful,” says Helen.
Unlike other introduced species, the experts aren’t worried that Scandinavian hoverflies would upset Scotland’s ecological balance. Rather, the concern is that imported individuals would struggle in Scotland, meaning serious wasted effort for the conservationists and a poor outcome for the species.
For example, Swedish hoverflies can use spruce trees for their breeding habitat – something their Scottish cousins have never been observed to do. The amount of freezing and thawing that the Scandinavian hoverflies have adapted to could also be incompatible for the Scottish climate.
“Having a (reference) genome means we can look at marked differences in actual genes,” explains Heather. “This might be the case for habitat adaptation, or it might not. We don’t know whether this is a learned behaviour or has a genetic basis. We’re looking for any red flags in the genetic data that suggest bringing them over from Scandinavia would be a bad idea.”
Genomics alone will not cement the Pine Hoverfly’s return to Scottish forests. At every stage of this years-long conservation effort the multi-disciplined team has drawn on a wide range of ecological and behavioural data and expertise. Nevertheless, being able to probe the genetic makeup of these rare insects thanks to a high-quality reference genome is a potential gamechanger. And that applies to many insect species.