Chris Gomersall / 2020VISION / Seven spot ladybird (Coccinella septempunctata) on Black knapweed (Centaurea nigra) flower at RSPB's Hope Farm Reserve, Cambridgeshire, England, UK, July

Nick Garbutt / Common knapweed (Centaurea nigra), close up. North Tyrol, Austria, June.

Nick Garbutt / Common knapweed (Centaurea nigra) in ancient alpine meadow with hut. in distance, North Tyrol, Austria. June 2018.

Nick Upton / Colony of Large knapweed aphids (Uroleucon jaceae) feeding on Black / Common knapweed (Centaurea nigra) stem, Mellis Common, Suffolk, UK May.

Phil Savoie / Six spot burnet moth (Zygaena filipendulae) on Black knapweed (Centaurea nigra) Pentwyn farm SSSI, Gwent Wildlife Trust, Monmouthshire Wales UK, July.

Andy Sands / Chalkhill blue butterfly (Polyommatus coridon) male feeding on flower of Knapweed (Centaurea nigra), Hertfordshire, England, UK August

Phil Savoie / Six spot burnet moth (Zygaena filipendulae) in flight over grass meadow with flowering Black knapweed (Centaurea nigra), Cats ear (Hypochaens radicata), Common spotted Orchid (Dactylorhiza fuchsii) f...

Phil Savoie / Six spot burnet moth (Zygaena filipendulae) in flight over meadow with flowering Black knapweed (Centaurea nigra), Cats ear (Hypochaens radicata), Common spotted Orchid (Dactylorhiza fuchsii) flowers...

Phil Savoie / Grass meadow with flowering Black knapweed (Centaurea nigra), Cats ear (Hypochaens radicata), Common spotted orchid (Dactylorhiza fuchsii), flowers, SSSI, Pentwyn Farm Gwent Wildlife Trust, Monmouths...

Sue Daly / Common knapweed (Centaurea nigra) Sark, British Channel islands, September.

Sue Daly / Common knapweed (Centaurea nigra) Sark, British Channel islands, September.

Terry Whittaker / Humming-bird hawk-moth (Macroglossum stellatarum) feeding on Common knapweed (Centaurea nigra). Chalk cliffs, Kent. July