Even local naturalists like myself would automatically assume these were Six Spot Burnet Moths, as that has been the only species of Burnet Moth familiar to us for many years.
During a recent butterfly and moth audit for a client, I counted more than 900Burnet Moths, which I took to be the usual Six Spot Burnet with six spots on each wing.
When I gave a summary of this on the local butterfly enthusists’ website, a fellow naturalist replied telling me Five Spot Burnets had been reported locally.
Jokingly, he suggested I go back and count the spots on every one of the Burnet Moths I had surveyed!
Fortunately, I had taken lots of pictures of flowerheads smothered in Burnet Moths, so thought I would have a quick flick through them to see if there might be a solitary Five Spot Burnet among them.
Imagine my amazement to discover that every last one of them was a Narrow Bordered Five Spot Burnet!
Obviously this species has been staging a silent colonisation of the coastal strip largely unnoticed, as naturalists continued to assume all local Burnet Moths were Six Spots.
This revelation has caused me to flick back through all Burnet Moth pictures I have taken since spring.
It turns out most of those seen in spring were the usual Six Spots, gradually changing to almost entirely Five Spots by July.
So it would seem the old species tends to hatch earlier than the new one.
This explains why I was still seeing so many unhatched cocoons long after there were lots of Burnet Moths on the wing.
It also shows why naturalists should never assume a familiar species is indeed what it appears to be.
So from now on when you see these shockingly pink day flying moths, count the spots.
You may make the acquaintance of the coast’s latest invader – the Narrow Bordered Five Spot Burnet Moth!
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