🦋

Swallowtail

Papilio machaon

Not yet photographed by the community

UK's largest butterfly; restricted to Norfolk Broads fenland.

Species Profile

UK Red List; Nationally Scarce species and protected under UK wildlife legislation

Lifespan: 2–6 weeks as an adult butterfly; complete life cycle from egg to adult takes approximately 4–6 weeks depending on temperature
Size & Weight: Wingspan 64–100 mm; one of the UK's largest native butterflies
Habitat: Open, sunny areas with fenland, marshland, and coastal habitats where milk parsley and other umbelliferous plants grow.
UK Distribution: Restricted to Norfolk and a few other East Anglian fens; formerly more widespread across southern England. Resident population with occasional continental migrants in summer.
Diet: Adults feed on nectar from teasels, thistles, marjoram, and other flowering plants; caterpillars feed exclusively on umbellifers, particularly milk parsley, fennel, and wild carrot.
Predators: Birds (particularly robins and wrens), spiders, parasitic wasps, and ground predators of caterpillars and pupae
Mating Season: May to August, typically in two broods per year
Breeding: Females lay single eggs on food plants; caterpillars take 2–3 weeks to develop; pupation occurs either as a chrysalis that overwinters or develops into a second brood within 1–2 weeks
Behaviour: Swallowtails are powerful, rapid fliers with characteristic gliding flight; males patrol territories and perch on vegetation in warm sunshine. They are highly territorial and males engage in aerial contests. The species is notably sensitive to habitat disturbance and requires specific wetland conditions.

Did You Know?

•The caterpillar has striking orange eversible tentacles (osmeterium) that release a pungent smell as a defence mechanism against predators
•The hindwings have distinctive tail-like projections that resemble swallows, giving the species its common name
•UK populations are genetically distinct and represent the northern limit of the species' range; continental populations are significantly larger
•Caterpillars undergo a dramatic colour change from black with orange bands to bright green as they mature, providing camouflage on their food plants
•The species is an indicator of high-quality fen habitat and its presence indicates healthy wetland ecosystems

🦋

No photos yet

Be the first to photograph a Swallowtail and share it with the community.