NATURE FOCUS BRIMSTONE BUTTERFLY
AS the days warm up in late March we are often treated to the early sight of butterflies on the wing.
These are adults which emerge from their hibernation to take advantage of the increasing warmth of the sun.
One of these early butterflies is the Brimstone butterfly.
This is easy to identify from the other common but more colourful Peacock, Small Tortoiseshell and Red Admiral butterflies which also hibernate.
Brimstones are medium to large butterflies.
The female’s wings are very pale green, and can be almost white, while the males have yellow-green underwings and yellow upper wings. When resting amongst foliage their angular shaped wings and distinct wing venations provide every effective camouflage due to the resemblance of their wings to leaves.
It is believed that the term “butterfly” originated from the male Brimstone’s sulphur-yellow colouration. Females can often be mistaken for Large White butterflies, but on closer inspection can be distinguished by the distinctive points on their wing tips.
Brimstones can be spotted during most months of the year although their numbers peak in April and May as overwintering adults emerge, and again in August as the offspring of the early population mature into adults.
The adults that emerge in spring feed on the nectar from a variety of flowers such as dandelion, primrose, cowslip, bugle, and bluebell and can live for up to 11 months.
The UK population of the Brimstone butterfly is very stable and is spreading northwards as a result of climate change.
They are a very mobile species and can be found in most habitats in the UK although their larvae only feed on native Buckthorn and Alder Buckthorn.
The planting of these species in gardens will encourage adult females to lay their pale green, skittle-shaped, eggs on the underside of the fresh leaves in spring.
The larvae (caterpillars) hatch after two weeks and undergo four moults as they mature; each of these stages is known as an instar.
The larvae are blueish green in colour with a white stripe and feed on the edges of the leaves, and their presence is given away by the very visible damage they cause to leaves.
They often rest in a characteristic “humped” posture along the midrib of a leaf.
After around four weeks the fullygrown larvae move away from the food plant and pupate on the underside of leaves on nearby foliage, attached by a silk thread.
The pupa (chrysalis) is green with purple markings and shaped like a curled-up leaf, so can be hard to spot.
It only takes a further two weeks for the adult butterfly to develop.
The newly hatched adults show a preference to feed on nectar-rich purple flowers such as thistle and devil’s-bit-scabious.
Due to their long proboscises, they can feed on flowers such as teasel which is not possible by many other butterfly species.
As with other butterflies the proboscis is rolled up out of the way when not in use.
This ability to feed on a wide range of flowers ensures that they build up the appropriate energy reserves to last them through the winter months where they hibernate in the dense foliage of ivy, holly and bramble ready to start the cycle over again.
Keep a look out on warm and sunny spring days for the sight of a Brimstone butterfly or one of the other emerging species which is a real sign that warmer days are not too far away.
If you are interested in identifying other butterflies that can often be seen in our gardens and local parks go to https://www.wildlifetrusts.org/ wildlife/identify-british-butterflies.
EARLIER this week, among the pomp and ceremony of the Queen’s speech were announcements on two pieces of legislation that will be pivotal to our nation’s ability to secure nature’s recovery.
This was the third successive Queen’s Speech to promise to pass an Environment Bill – and with half of all wildlife already in serious decline it is essential that we hold the Government’s feet to the fire to ensure the Bill becomes law this time around.
In the race to turn nature’s decline into nature’s recovery there is no time to lose and it is vital that the Government brings back the Bill as a matter of urgency.
Once it’s back in parliament there must be a determination to deliver it as quickly as possible. We won’t be able to tackle the climate crisis and meet our net zero target without similar ambition to meet the nature crisis head on – the two are inextricably linked and if the Government intends to keep to its commitment of passing the Bill before the COP26 climate change conference in November, it really needs to be back in Parliament before the end of the month.
You have to hope that the Government has used the further delay to the Bill to strengthen it, because despite the Prime Minister’s stated ambition to be a world leader in environmental terms, we live in one of the most naturedepleted countries in the world.
The Bill must enshrine the Prime Minister’s commitment to turn around nature’s decline by 2030 in law.
A straightforward, legally binding target to reverse the loss of nature within the decade would force all parts of Government to take urgent action to help bring nature back.
While we welcome the return of the Environment Bill there are real concerns that the Planning Bill could dramatically undermine its effectiveness by turning back the clock to what the CPRE have described as a “deregulated dark age of development”.
Any new legislation to modernise the planning system must also help focus efforts to tackle the nature and climate crisis, and Government must recognise that the obstacle to house building is not environmental protections, but the shocking delays in turning thousands upon thousands of unused planning permissions already granted into homes for people.
One way the Planning Bill can make a direct contribution to the recovery of nature is through a new Wildbelt – a bold designation which will protect land that’s put into recovery for nature. It would also help tackle climate change and with levelling-up access to green space. As the new session of Parliament gets under way we must see more joined-up thinking from the Government which, on the one hand, is talking up its commitment to world-beating legislation to ensure they leave nature in a better state, whilst also proposing relaxations of planning rules which could lead to further loss of habitat and restrict councils’ ability to protect local sites from developers.
The past year has demonstrated just how much nature means to so many of us and as we move forward we must ensure we have a robust legal framework that not only tackles issues such as climate change and pollution but also provides the safeguards needed to prevent further loss of wildlife habitat and to protect species under threat.
With the impacts of the climate and nature crises racing ahead there really is no time to lose and in the weeks and months ahead the Government must find a way to bridge the gap between the Prime Minister’s public pronouncements on environmental commitments and the decisions his Government actually takes day to day.
To find out more about our efforts to stand up for wildlife and be kept up to date with our latest campaigns visit wildlifetrusts.org/get-involved/ our-campaigns