Butterflies are not only appreciated for their beauty and grace, but play an important role in the pollination of flowers. There are 56 species of butterfly in the UK, with many of them under threat from environmental change. There have been serious losses of butterfly habitats, such as wildflower meadows, and in recent times climate change is altering the range and distribution of many species. You can help butterfly populations, by providing habitats and food.
- Butterflies do not have any lips or teeth, just a long coiled tongue.
- Most butterflies only lay their eggs on a few selective host plants, with each species having a preference for different plant types.
- Butterflies can select suitable plants by a combination of sight, smell and taste, with the butterfly identifying chemicals from the plant which signals it being a suitable host species for food.
- When an adult butterfly emerges from a pupa, the butterfly pumps fluid into its wings to expand them which is followed by a hardening process to allow the butterfly to fly.
- Butterflies in all stages of their life are preyed on by a wide variety of predators in the form of mammals, birds, spiders and other insects.
- Adult butterflies use colour to attract mates and avoid predation, but also to raise their body temperature by basking and warming up. This is particularly important in British butterflies.
- A butterfly has thousands of lenses in its eyes.
What is the life cycle of a butterfly?
Butterflies are the final manifestation of a four-stage sequence that starts with an egg. The egg (ovum) becomes a caterpillar (larva), which then turns into a chrysalis (pupa) and finally becomes a butterfly (imago). The life span of an adult butterfly depends on the species and, to some extent, on weather conditions. A small species such as a common blue may live for only a few days, whereas the larger peacock may emerge from its pupa in early August and after feeding up, hibernating, mating and laying eggs, it may still be on the wing in early June the following year.
Most British butterflies overwinter as either eggs (the white letter hairstreak and silver washed fritillary), some as caterpillars (small copper and meadow brown), some as pupae (orange tip and holly blue) and some as adults (brimstone and small tortoiseshell). Some species, like the painted lady, cannot withstand our winters and migrate northwards from their breeding areas each spring. The speckled wood can overwinter as either a caterpillar or a chrysalis.
Some species are more mobile than others. Clouded yellow and painted lady can reach the UK from continental Europe. Whilst others are mobile but not migrants – such as the holly blue, brimstone and orange tip which all wander through the countryside. However, most of our species are very localised and live in sedentary colonies, such as the silver-studded, adonis blue and pearl-bordered fritillary.
Protection against predators
Caterpillars and adults have evolved a range of special defences to protect against predation; including spines, chemicals, camouflage and an association with ants which are aggressive and protect caterpillars and some adult species such as the blues. Butterflies and caterpillars can merge with their background to make it harder for predators to see them. Species like green hairstreak are very hard to see when resting on a leaf. Some species use mimicry. The black hairstreak and comma species can look like bird droppings. Some caterpillars, like the large white larva, use warning colours like blacks and yellows – sending a warning to predators “don’t eat me!” And some caterpillars use chemical defences, like the swallowtail which has foul-smelling organs it can push out when danger threatens.
What’s threatening British butterflies?
Butterflies are attractive insects as well as valuable pollinators for plants, fruit and vegetables. They also give nature lovers a great deal of pleasure. In most cases, our butterflies have very specific habitat requirements which are affected by changes in their environment. In a fast changing British landscape, pressure is now causing serious declines in many species. Intensive agricultural practices and woodland management are some of the main factors in this decline. Since the 1940s, 97% of flower meadows have been lost together with large areas of chalk downland and ancient woodland. One example of a species on the edge is the high brown fritillary, which has declined by 94% in recent years.
Some of our butterfly species are legally protected, with species like the heath, marsh and brown fritillaries, large copper, large blue and swallowtail being afforded full protection. Many species cannot be caught in the wild or sold. These include the purple emperor, northern brown argos, pearl bordered and Glanville fritillaries, chequered, silver-spotted and Lulworth skippers, small, silver-studded, chalkhill and Adonis blues, large heath, mountain ringlet, wood white, large tortoiseshell and the black, brown and white-letter hairstreaks.
How can I make my garden butterfly friendly?
Gardens provide essential habitat for butterflies and moths all over the UK and a much-needed source of food through flowers and plants. As well as planting nectar-producing flowers, letting an area of your garden grow wild and allowing the grasses to grow tall could attract a range of regular visitors to your garden – including meadow brown, speckled wood, gatekeeper, small skipper, marbled white and ringlet.
Top tips for butterfly friendly gardens
Have flowers available throughout the season, but particularly in spring when early emerging butterflies need energy and in the autumn when some species need to build up their reserves up for the winter. Prune some of your buddleia in March to ensure late flowering nectar production is greater if plants are kept well watered. Always buy genuine UK wildflower plants and seeds, as exotic species may not be suitable for butterflies. Grow caterpillar plants as well as flowering species. Limit the spread of stinging nettles by growing them in a large container sunk into the ground. Avoid buying commercially produced garden compost, as this is often sourced from peat bog habitats at the expense of wildlife including rare species of butterfly, like the large heath. Go green and avoid using insecticides and herbicides in your garden. This will promote beneficial insects such as butterflies and bees, plus lacewing, ladybirds and even mammals like hedgehogs which control pest species such as aphids and slugs.
What to plant and when, for Butterflies
Spring nectar: Aubretia, bluebell, clover, cuckooflower, daisy, dandelion, forget-me-not, honesty, pansy, primrose, sweet rocket and wallflower.
Late summer/autumn: Buddlea, french marigold, ice plant, ivy, knapweed, lavender, marjoram, michaelmus daisy, mint, red valerian, scabious and thyme.
Planting for Caterpillars
Stinging Nettles: comma, red admiral and moths such as scarlet tiger, spectacle small magpie and stout Holly and Ivy: Holly blue Buckthorn and alder buckthorn: Brimstone Cuckooflower and Garlic Mustard: Orange-tip and green-veined white Hop: Comma and moths such as buttoned snout, angle shades and dark spectacle. Common Bird’s-foot Trefoil: Common blue
Useful Butterfly Contacts
Tel: 01929 400209