Solvin Zankl / Gall wasp (Cynips quercusfolii) emerging from the oak gall. Germany, October.

Duncan Mcewan / Silk button spangle galls on Oak casued by Wasp (Neuroterus albipes). Scotland, UK, Europe

Colin Varndell / Knopper gall of the gall wasp (Andricus quercuscalicis) Dorset, England, UK, September.

Steve Downer / Gall wasp (Biorhiza pallida) emerging from a gall on an Oak (Quercus) tree, UK, June.

Will Watson / Nettle clustercup rust fungus (Puccinia urticata) induced gall on Common nettle (Urtica dioica), Westhope Common, Herefordshire, England, UK, May.

Robert Thompson / Spangle gall wasp (Neuroterus quercusbaccarum) galls on oak leaf, Clare Glen, County Armagh, Northern Ireland, October.

Philippe Clement / Robin's pincushion gall, caused by the gall wasp (Diplolepis rosae) on Dog rose, Luxembourg, August

Will Watson / Artichoke gall caused by a midge (Taxomyia taxi), on Yew (Taxus baccata) Leominster Priory, Herefordshire, England, UK, October 2016.

Melvin Grey / Yellow bishop (Euplectes capensis crassirostris) adult male, calling from a branch covered in Galls. Ngorongoro crater, Tanzania

Colin Varndell / Gall on oak acorn made by larva of Knopper gall wasp (Andricus quercuscalicis), Dorset, UK, August.

Colin Varndell / Silk button galls on the underside of Pedunculate oak leaf (Quercus robur) caused by the Gall wasp (Neuroterus numismalis). Dorset, UK, September.

Colin Varndell / Cherry gall of the Gall wasp (Cynips quercusfolii) on the underside of Pedunculate oak leaf (Quercus robur). Dorset, UK, September.

Colin Varndell / Common spangle galls of Cynipid wasp (Neuroterus quercusbaccarum) on the underside of Pedunculate oak leaf (Quercus robur). Dorset, UK September.

Chris Mattison / Knopper Oak gall remains, caused by the wasp (Andricus quercuscalicis) Forest of Dean, Gloucestershire, UK May

Stephen Dalton / Oak (Quercus robur) apple/ gall caused by a small parasitic wasp, Extermadura, Spain

Nick Upton / Cherry galls caused by Gall wasp (Cynips quercusfolii) on leaves of Pedunculate / English oak (Quercus robur), GWT Lower Woods reserve, Gloucestershire, UK, September.

Alex Hyde / Gall of the Gall Midge (Mikiola fagi) on a Beech leaf (Fagus sylvatica). Plitvice Lakes National Park, Croatia. November.

Solvin Zankl / Gall wasp (Cynips quercusfolii) emerging from gall in oak. Germany. October.

Solvin Zankl / Female Gall wasp (Cynips quercusfolii) emerging from the oak gall, Germany. October.

Solvin Zankl / Gall wasp (Biorhiza pallida) gall on oak tree Niedersechsische Elbtalaue Biosphere Reserve, Elbe Valley, Lower Saxony, Germany, May.

Solvin Zankl / Knopper gall (Andricus quercuscalicis) on oak tree acorn, and Common spangle gall (Neuroterus quercusbaccarum) on oak tree leaf. Bavaria, Germany

Solvin Zankl / Oak spangle gall (Neuroterus numismalis) on oak tree leaf, Niedersechsische Elbtalaue Biosphere Reserve, Elbe Valley, Lower Saxony, Germany

Solvin Zankl / Gall wasps (Biorhiza pallida) mating as they emerge from the oak tree gall. Elbe, Germany, June.

Solvin Zankl / Common spangle gall (Neuroterus quercusbaccarum) on oak tree leaf. Niedersechsische Elbtalaue Biosphere Reserve, Elbe Valley, Lower Saxony, Germany, August.

Solvin Zankl / Gall wasp (Biorhiza pallida) gall on oak tree, Niedersechsische Elbtalaue Biosphere Reserve, Elbe Valley, Lower Saxony, Germany, June.

Alex Hyde / Robin's pincushion gall caused by Gall wasp (Diplolepis rosae) on wild Dog rose (Rosa canina), Peak District National Park, Derbyshire, UK. September.

Colin Varndell / Artichoke galls (Andricus fecundator) on Pedunculate oak. Dorset, UK, August.

Kim Taylor / Oak marble-galls caused by Gall wasp (Andricus kollari). Surrey, England, September.

Rod Williams / Robin's Pincushion gall on Dog Rose, caused by gall wasp (Diplolepis rosae) Hutchinson's Bank, New Addington, Croydon, South London, England, UK, August

Alex Hyde / Pin Cushion Gall caused by Gall wasp (Diplolepis rosae) on wild Dog Rose (Rosa canina), Peak District National Park, Derbyshire, UK. August.

John Abbott / Oak Gall wasp (Andricus quercusflocci) gall, Brackenridge Field Laboratory, Austin, Travis County, Texas, USA.

Paul Harcourt Davies / Medusa's Head Gall (Andricus caputmedusae) an oak gall caused by a small wasp of the Cynipidae family. Montecucco, Orvieto, Umbria, Italy, September.

Paul Harcourt Davies / Oak Gall caused by Gall wasp (Andricus quercustozae) Podere Montecucco, Orvieto, Umbria, Italy, September.

Paul Harcourt Davies / Purplish brown, sticky oak gall caused by Gall wasp (Andricus dentimitratus) Podere Montecucco, Orvieto, Umbria, Italy, September.

Adrian Davies / Silk button spangle galls on an English oak (Quercus robur) leaf caused by a gall wasp (Neuroterus numismalis), Surrey, England, UK, September.

Adrian Davies / Knopper galls on English oak (Quercus robur) acorns, Knopper galls are chemically induced distortions caused by gall wasps (Andricus quercuscalicis) laying eggs in the acorn buds, Surrey, England, UK,...

Alex Hyde / Cowberry (Vaccinium vitis-idaea), with a gall caused by Cowberry Redleaf fungus (Exobasidium vaccinii). Peak District National Park, Derbyshire, UK. November.

Georgette Douwma / Silk button spangle galls caused by the gall wasp (Neuroterus numisalis) and Common spangle galls caused by another Gall wasp (Neuroterus quercusbaccarumon) on the underside of an English oak leaf (Qu...

Georgette Douwma / Silk button spangle galls caused by the Gall wasp (Neuroterus numisalis) and Common spangle galls caused by another gall wasp (Neuroterus quercusbaccarumon) on the underside of an English oak leaf (Qu...

Georgette Douwma / Close up of Common spangle galls caused by the gall wasp (Neuroterus quercusbaccarum) on the underside of an English oak (Quercus robur) leaf. UK.

Georgette Douwma / Silk button spangle galls caused by the gall wasp Neuroterus numisalis and Common spangle galls caused by the gall wasp Neuroterus quercusbaccarumon on the underside of an English oak leaf (Quercus ro...

Georgette Douwma / Close up of Common spangle galls caused by the gall wasp (Neuroterus quercusbaccarum) on the underside of an English oak (Quercus robur) leaf. UK.

Georgette Douwma / Close up of Common spangle galls caused by the gall wasp (Neuroterus quercusbaccarum) on the underside of an English oak (Quercus robur) leaf. UK.

Georgette Douwma / Silk button spangle galls caused by the Gall wasp (Neuroterus numismalis) and Common spangle galls caused by another (Neuroterus quercusbaccarumon) on the underside of an English oak leaf (Quercus rob...

Georgette Douwma / Silk button spangle galls caused by the gall wasp Neuroterus numisalis on the underside of an English oak leaf (Quercus robur) UK.

Georgette Douwma / Silk button spangle galls caused by the Gall wasp (Neuroterus numisalis) and Common spangle galls caused by another gall wasp (Neuroterus quercusbaccarumon) on the underside of an English oak leaf (Qu...

Georgette Douwma / Silk button spangle galls caused by the gall wasp (Neuroterus numismalis) on the underside of an English oak leaf (Quercus robur) UK.

Georgette Douwma / Close up of Common spangle galls caused by the gall wasp (Neuroterus quercusbaccarum) on the underside of an English oak (Quercus robur) leaf. UK.

Doug Wechsler / Gall (Polystepha pilulae) on Pin Oak (Quercus palustris) Morris Arboretum, Philadelphia, Pennsylvania, USA, August.

Kim Taylor / Beech Pouch Gall Midge (Mikiola fagi) galls of beech leaves (Fagus sp.) Croatia, June,

Denis-Huot / Whistling thorn (Acacia drepanolobium) galls occupied by mutualist ant (Crematogaster sp) Kenya

Mark MacEwen / Patas Monkey / Wadi monkey / Hussar monkey (Erythrocebus patas) eating ant galls, Laikipia game reserve, Kenya, Africa.

Mark MacEwen / Patas Monkey / Wadi monkey / Hussar monkey (Erythrocebus patas) eating ant galls, Laikipia game reserve, Kenya, Africa.

Colin Varndell / Robin's pincushion gall caused by wasp (Diplolepis roase) on dog rose (Rosa canina). Dorset, UK September 2012

Laurie Campbell / Oak spangle gall (Neuroterus quercusbaccarum) on the underside of a sessile / durmast oak leaf, Roxburghshire, Scotland, September

Laurie Campbell / Cherry gall (Diplolepis quercusfolii) on underside of oak leaf with Oak spangle galls (Neuroterus quercusbaccarum) Loch Lomond and the Trossachs National Park, Stirlingshire, October

Simon Colmer / Plant gall (Tetraneura ulmi) on Wych elm (Ulmus glabra) UK

Simon Colmer / Robin's Pincushion / Bedeguar Gall on rose, caused by the tiny Gall wasp (Diplolepis rosae) Levin Down Nature Reserve, Sussex, UK, August

Simon Colmer / Robin's Pincushion / Bedeguar Gall on rose, caused by the tiny Gall wasp (Diplolepis rosae) Levin Down Nature Reserve, Sussex, UK, August

Simon Colmer / Robin's Pincushion / Bedeguar Gall on rose, caused by the tiny Gall wasp (Diplolepis rosae) Levin Down Nature Reserve, Sussex, UK, August

Simon Colmer / Lime nail / bugle galls on Lime leaf caused by Gall mite (Eriophyes tiliae) Sussex, UK, July

Simon Colmer / Lime nail / bugle galls on Lime leaf caused by Gall mite (Eriophyes tiliae) Sussex, UK, July

Simon Colmer / Lime nail / bugle galls on Lime leaf caused by Gall mite (Eriophyes tiliae) Sussex, UK, July

Colin Varndell / Common spangle galls of the Gall wasp (Neuroterus quercusbaccarum) on underside of oak leaf, Dorset, UK, September

Colin Varndell / Common Spangle Galls of the Gall Wasp (Neuroterus quercusbaccarum) on underside of oak leaf. Dorset, UK, September.

Ross Hoddinott / Marble galls of Oak marble gall wasp (Andricus kollari) on twig of English oak (Quercus robur). Broxwater, Cornwall, UK, August

Stephen Dalton / Common oak gall wasp (Cynips quercusfolii) exposed inside oak gall, UK

Paul Harcourt Davies / Galls forming on Holm oak (Quercus coccifera) Italy

Ross Hoddinott / Spangle galls on oak leaf caused by Spangle gall wasp {Neuroterus quercusbaccarum}, Cornwall, UK. October.

Mark Moffett / Millipede (Narceus americanus) with galls and mold inside acorn, Massachusetts

Paul Hobson / Oak "apples" on Oak tree leaf (Quercus sp) caused by larva of gall wasp, UK

Jason Smalley / Common spangle galls on oak leaves caused by Spangle gall wasp {Neuroterus quercusbaccarum} Lancashire, UK

Doug Wechsler / Round Goldenrod gall caused by larva of Goldenrod gall fly {Eurosta solidagnis} Pennsylvania, USA

Duncan Mcewan / Smooth pea galls on Dog rose leaves {Rosa canina} caused by gall wasp {Diploepis eglanteriae} UK

Chris O'Reilly / Silk button and Common spangle galls of Gall wasps {Neuroterus spp} on oak leaf. UK

Chris O'Reilly / Silk button spangle galls (Neuroterus numismalis) on oak leaf, UK

Jason Smalley / Common spangle galls on oak caused by wasp (Neuroterus quercusbaccarum) Lancashire, UK

Chris O'Reilly / Cherry galls on Oak sapling caused through parasitism by {Cynips quercusfolii} gall wasp, Mixed woodland, Spring, Derbyshire, UK

Chris O'Reilly / Cherry galls on oak sapling caused through parasitism by {Cynips quercusfolii} gall wasp, Mixed woodland, Spring, Derbyshire, UK

Duncan Mcewan / Spangle galls, early development on Oak leaf caused by Spangle gall wasp {Neuroterus quercusbaccarum} UK

Chris O'Reilly / Artichoke gall {Andricus fecundator} on Oak tree, Derbyshire, UK

Chris O'Reilly / Artichoke gall {Andricus fecundator} on Oak tree, Derbyshire, UK

Chris O'Reilly / Robin's pincushion gall {Diplolepis rosae} on Dog rose {Rosa canina} Derbyshire, UK

Philippe Clement / White spruce tree {Picea glauca} showing burl, a spherical woody growth caused by fungi, insects or bacteria, Denali NP, Alaska, USA

Philippe Clement / Cherry gall on oak leaf caused by Gall wasp {Cynips quercusfolii} Belgium

Kim Taylor / Oak marble gall section showing larva of gall wasp {Andricus kollari} UK.

Kim Taylor / Oak marble gall section showing larva of gall wasp {Andricus kollari} UK.

Adrian Davies / Pin cushion gall caused by Gall wasp {Diplolepis rosae} on wild dog rose, UK.

Anup Shah / Patas monkey feeds on galls of Whistling acacia tree, Kenya 2002 {Erythrocebus patas}

Anup Shah / Patas monkey feeds on seeds of Whistling acacia tree, Kenya 2002 {Erythrocebus patas}

Anup Shah / Young Patas monkey feeds on galls of Whistling acacia tree, Kenya 2002 {Erythrocebus patas}

Kim Taylor / Larva of Oak Marble Gall wasp (Andricus kollari) in gall, cross-section, UK.

Brian Lightfoot / Cherry Gall on Oak leaf caused by gall wasp, Cynips quercusfolii, Scotland

Duncan Mcewan / Cherry Gall cut away to show Gall wasp larva (Cynips quercusfolii) inside. On oak tree leaf.

Duncan Mcewan / Cherry gall cut away to see wasp larvae (Cynips quercusfolii). Scotland, UK, Europe

Duncan Mcewan / Cherry galls developing on young oak leaf caused by gall wasp (Cynips quercusfolii). Scotland, UK, Europe