Thomas Marent / Oldworld Swallowtail (Papilio machaon) caterpillar, Switzerland

Paul Harcourt Davies,Paul Harcourt Davies / Common Swallowtail butterfly (Papilio machaon) backlit showing wing structure. Podere Montecucco, Orvieto, Umbria, Italy, October

Paul Harcourt Davies,Paul Harcourt Davies / Apollo butterfly (Parnasius apollo) feeding on flower, Mount Terminillo, Rieti, Lazio, Italy, July 2011

Terry Whittaker / 2020VISION / Swallowtail Butterfly (Papilio machaon britannicus) on hawkbit flower. Strumpshaw Fen, Norfolk, June.

Terry Whittaker / 2020VISION / Swallowtail Butterfly (Papilio machaon britannicus) on hawkbit flower. Strumpshaw Fen, Norfolk, June.

MYN / Paul Harcourt Davies / Caterpillar larva of Southern festoon butterfly (Zerynthia polyxena cassandra) on foodplant (Aristolochia rotundifolia) Italy, May. meetyourneighbours.net project

Konrad Wothe / Cairns birdwing butterfly (Ornithoptera priamus) male on fern leaf and Blue Mountain Swallowtail butterfly in flight, Atherton Tablelands, Queensland, Australia, October

Alex Hyde / Common Swallowtail butterfly (Papilio machaon) resting on Meadow Clary (Salvia pratensis) flowers, on a white background. Nordtirol, Tirol, Austrian Alps, Austria, 1700 metres altitude, July.

Alex Hyde / Common Swallowtail butterfly (Papilio machaon) resting on Meadow Clary (Salvia pratensis) flowers, on a white background. Nordtirol, Tirol, Austrian Alps, Austria, 1700 metres altitude, July.

Alex Hyde / Common Swallowtail Butterfly (Papilio machaon) resting on Viper's Bugloss / Blueweed (Echium vulgare) in alpine meadow. Nordtirol, Tirol, Austrian Alps, Austria, 1700 metres altitude, July.

Alex Hyde / Common Swallowtail Butterfly (Papilio machaon) resting on Viper's Bugloss / Blueweed (Echium vulgare) in alpine meadow. Nordtirol, Tirol, Austrian Alps, Austria, 1700 metres altitude, July.

B&S Draker / Pipevine Swallowtail Butterflies (Battus philenor) pair mating close-up. Sinton, Corpus Christi, Coastal Bend, Texas, USA, June.