Silvia Reiche / Oldworld Swallowtail (Papilio machaon) caterpillar on fennel, Netherlands

MYN / Paul Harcourt Davies / Horsefly (Tabanus bovinus) close up of male feeding on fennel flower nectar (the females are blood suckers) Lazio, Italy, July. meetyourneighbours.net project

Wild Wonders of Europe / Lilja / Giant fennel (Ferula communis) flower, Kaplica, Northern Cyprus, April 2009

Wild Wonders of Europe / Lilja / Giant fennel (Ferula communis) plants in flower, Kaplica, Northern Cyprus, April 2009

Wild Wonders of Europe / Bartocha / Giant Fennel (Ferula communis) in flower, Gargano National Park, Gargano Peninsula, Apulia, Italy, April 2008

Jose B. Ruiz / Giant fennel {Ferula communis} at dusk, Spain.

Edwin Giesbers / Giant fennel (Ferula communis) flowering umbels. Cyprus. April.

Edwin Giesbers / Giant fennel (Ferula communis) flowering, Mediterranean sea in background. Cyprus. April.

Paul Harcourt Davies / Common swallowtail larva (Papilio machaon) final instar on larval foodplant Fennel (Ferula communis). The larval body has shortened and it is attached to the stem just before forming the chrysalis.

Paul Harcourt Davies / Common swallowtail larva (Papilio machaon) 2nd instar on larval foodplants Fennel (Ferula communis)

Paul D Stewart / Illustration of Swallowtail Butterfly (Papilio machaon) on Fennel by Maria Sybella Merian 1683, from her book 'Caterpillars, Their Wondrous Transformation and Peculiar Nourishment from Flowers'. Meri...

Nick Upton / Rock samphire / Sea fennel (Crithmum maritimum) flowering on a cliff edge, Ponta de Sagres, Algarve, Portugal, July 2013.