Brimstone butterfly in flight (Photo By Charles J. Sharp – Own work, from Sharp Photography, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=38298003)
A series following the 72 British mini-seasons of Nature’s Calendar by Kiera Chapman, Lulah Ellender, Rowan Jaines and Rebecca Warren.
Dear Readers, my response to the title of this piece is ‘not around here they ain’t’ – today is cold, windy and grey, with a speckling of raindrops, and I imagine that any self-respecting butterfly is hiding away in a crevice somewhere. But on milder, calmer days you may well spot a Brimstone butterfly scurrying along – Rebecca Warren describes the males as having a ‘wind-tossed sweet-wrapper’ appearance, and I couldn’t put it better myself! The females are not as brightly coloured, and both sexes disappear when they land and close their wings, so closely do they resemble a leaf.
Brimstone at rest (Photo from https://s3.animalia.bio/animals/photos/full/original/2560pxgonepteryx-rhamni-female-04-hs.webp)
Brimstones have very long tongues, which means that they can take advantage of the long corollas of primroses (which most other insects cannot). This is one reason why Brimstones emerge from hibernation so early, and why timing is everything – if there is nothing to feed on, the butterfly will die. Later, the insects will seek out buckthorn or alder buckthorn to lay their eggs on.
Orange tip butterfly at rest (Photo by Sarah Perkins/RES)
Brimstones aren’t the only ‘early flyers’ – Orange Tip butterflies can also be around on mild days in early spring. They don’t hibernate overwinter as an adult butterfly, but appear from their chrysalises, timing their emergence to the flowering of Garlic Mustard and Lady’s Smock. When the females land on a plant they can tell, via sensors on their feet, whether another female has already been there and laid a single tiny egg: if so, the new female will flitter off to find another plant, because sadly the caterpillars of this species are cannibalistic, and will eat the eggs or caterpillars of any subsequent females.
The caterpillars are easy to miss, but are superbly camouflaged to look just like the stems of Garlic Mustard.
Orange-tip (Anthocharis cardamines) caterpillar. Photo (By jean-pierre Hamon (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons)
Garlic Mustard….
On a warm day, all sorts of other butterflies might crop up as well: Peacocks and Red Admirals may emerge from hibernation, and be found sunning themselves on a wall or path. Butterflies have to reach an internal temperature of about 28 degrees Celsius before they can fly – as Rebecca Warren points out, this is why it’s so dangerous for a hibernating butterfly to emerge too early, because they may not be fast enough to escape predators, and there might not be enough nectar to top up their energy stores. More reason to plant some early-flowering nectar sources, lovely gardener friends!
Orange Tip in St Pancras and Islington Cemetery
Peacock sunning itself, April 2021