Guide to the

Wood Ants

of the UK

and related species

Stew­art Taylor

Wood Ants of the UK

This guide is aimed at any­one who wants to learn more about mound-build­ing wood­land ants in the UK and how to identi­fy the three ​‘true’ Wood Ant spe­cies: South­ern Red Wood Ant, Scot­tish Wood Ant and Hairy Wood Ant. The Blood-red Ant and Nar­row-headed Ant (which over­lap with the Wood Ants in their appear­ance, hab­it­at and range) are also included here. The Shin­ing Guest Ant is depend­ent on Wood Ants for sur­viv­al so is included in this guide to raise aware­ness of this tiny and over­looked species.

A fur­ther related spe­cies, Formica praten­sis is not included in this guide. It has been con­sidered extinct on main­land Bri­tain since 2005 and is now only found on Jer­sey and Guern­sey in the Brit­ish Isles.

Fund­ing by CLIF, Nation­al Parks Pro­tect­ors Pub­lished by the Cairngorms Nation­al Park Author­ity © CNPA 2021. All rights reserved.

Con­tents

What are Wood Ants? 02 Why are they import­ant? 04 The Wood Ant cal­en­dar 05 Colony estab­lish­ment and life cycle 06 Scot­tish Wood Ant 08 Hairy Wood Ant 09 South­ern Red Wood Ant 10 Blood-red Ant 11 Nar­row-headed Ant 12 Shin­ing Guest Ant 13 Com­par­is­on between Shin­ing Guest Ant and Slender Ant 14 Where to find Wood Ants 15 Nest mounds 18 Spe­cies dis­tri­bu­tions 19 Man­aging hab­it­at for wood ants 22 Sur­vey tech­niques and mon­it­or­ing 25 Record­ing Wood Ants 26 Con­ser­va­tion status of Wood Ants 27 Fur­ther inform­a­tion 28

What are Wood Ants?

Wood Ants are large, red and brown-black ants and in Europe most spe­cies live in wood­land hab­it­ats. They are known around the world as thatch or mound ants due to the moun­ded nests they build. There are 13 described spe­cies of these ants in Euras­ia and 19 spe­cies in North Amer­ica. Like all ants they are social and cooper­ate to look after the brood, care for the nest and source food.

Bio­logy and ecology

Wood Ants build large thatched mounds in which to live and aggress­ively defend both their nest and food resources. As their name sug­gests, they are asso­ci­ated with wood­land; con­i­fer­ous forest, mixed and broadleaf wood­land with well drained soils being favoured. Nests are usu­ally south or south-east facing to max­im­ise the amount of sun­light warm­ing the nest.

Nest mounds vary tre­mend­ously in size and shape, ran­ging from fist-sized to 2m tall. What you see above ground is at least mirrored (and some­times exceeded) under­ground. Intern­ally the nest con­tains a series of tun­nels and cham­bers con­tain­ing the queen, a nurs­ery for the brood and food stores. Tun­nel entrances can be opened or closed to main­tain optim­al tem­per­at­ure and humidity.

On the sur­face, the ​‘thatch’ is made of organ­ic mater­i­als such as pine needles, small twigs, moss, heath­er, dried grass and even pieces of lichen. The thatch acts like a sol­ar pan­el to raise the tem­per­at­ure of the nest above that of its sur­round­ings (a high tem­per­at­ure is cru­cial for brood devel­op­ment). The thatch also acts as an umbrella so that rain water trickles away from the nest, keep­ing it dry.

All spe­cies of ants in the UK hibern­ate over the winter. In mound-build­ing ants, they retreat to the under­ground parts of their nests where the tem­per­at­ure is stable and free of frost. The best time to look for act­ive nests is from spring to autumn. Ants emerge from hiberna­tion once tem­per­at­ures are con­sist­ently above freez­ing and ​‘swarm’ on the sur­face of the nest in sunny weath­er to warm them­selves (and boost the tem­per­at­ure of the nest). The move­ment of the ants swarm­ing on the nest sur­face in spring actu­ally makes an aud­ible sound.

Jenni Stockan Swarm­ing beha­viour of Wood Ant work­ers on the nest sur­face in spring. Queens rise to the sur­face at this time and can be iden­ti­fied by their lar­ger size in rela­tion to the work­ers and their large glossy abdomens.

Diet

Wood Ants are omni­vor­ous and prey on a wide range of oth­er inver­teb­rates. Cater­pil­lars, aph­ids, spiders, beetles and many oth­ers (includ­ing oth­er ants) are taken, their diet chan­ging to suit loc­al abund­ances of dif­fer­ent prey. Work­ers sub­due their prey by bit­ing and spray­ing form­ic acid. A small pro­por­tion of their diet includes seeds, tree sap and berry juices. They will also scav­enge on dead invertebrates.

Between 60% and 90% of the diet of the work­ers comes from hon­ey­dew pro­duced by aph­ids feed­ing on the sap of trees and shrubs. This sap is high in sug­ars and as the aph­ids feed they excrete excess sug­ars as hon­ey­dew. Ants ​‘milk’ the aph­ids of their hon­ey­dew, and in return pro­tect the aph­ids from pred­at­ors and even move them to bet­ter feed­ing grounds. The Blood-red Ant is pre­dom­in­antly pred­at­ory on oth­er ants but will also feed on seeds, ber­ries and take hon­ey­dew from aphids.

J.M.S.Robinson A South­ern Wood Ant (Formica rufa) work­er guard­ing a col­lec­tion of aphids.

Ants ​‘milk’ the aph­ids of their hon­ey­dew, and in return pro­tect the aph­ids from pred­at­ors and even move them to bet­ter feed­ing grounds.

Why are they important?

Not only are Wood Ants fas­cin­at­ing and beau­ti­ful insects in their own right, but they per­form a num­ber of import­ant roles in the forest eco­sys­tem, earn­ing them the status of ​“eco­sys­tem engineers”.

Wood Ants:

• Affect tree growth through their rela­tion­ship with aph­ids in the tree can­opy and through remov­al of insect herb­i­vores (e.g. moth caterpillars)

• Accu­mu­late huge amounts of organ­ic mater­i­al and min­er­als in their nests, par­tic­u­larly nitro­gen and phos­phor­us (the nests not only increase the amount of min­er­al nutri­ents but also make them more avail­able to plants)

• Help dis­trib­ute the seeds of plants, includ­ing some plant spe­cies which have sug­ary coat­ings on their seeds to make them attract­ive to ants

• Are used by a range of bird spe­cies to remove para­sites (beha­viour known as ​‘ant­ing’ birds aggreg­ate the sur­face of the nest, caus­ing the ants to spray form­ic acid onto the bird’s feath­ers which kills parasites)

In addi­tion Wood Ants are a food source for ver­teb­rates such as Caper­cail­lie, Badger and Pine Marten to name a few. Some spe­cies spe­cial­ise in feed­ing on Wood Ants, such as the Green Wood­peck­er and the Gal­lows Spider.

The Wood Ant’s nest is home to a unique com­munity of spe­cial­ist inver­teb­rates. This includes the Shin­ing Guest Ant but also spe­cially adap­ted beetles, moths and even wood­lice which live inside ant mounds and nowhere else. There is also a con­cen­tra­tion of micro- organ­isms with­in Wood Ant nests which break­down unwanted food and nest materials.

Hay­ley Wiswell Larva of the beetle Clytra quad­ri­punctata with its case made of plant mater­i­al. The lar­vae wander about on the sur­face of Wood Ant nests feed­ing on plant debris and use their case as pro­tec­tion from the Wood Ant workers.

The Wood Ant calendar

This is gen­er­al­ised across the spe­cies in this guide and tim­ing of events will vary between spe­cies and parts of the UK, nest alti­tude, loc­al cli­mate etc.

Novem­ber – February/​March	June – September
Hiberna­tion	Rais­ing work­er offspring

March – April	May — June
Spring swarm­ing (Wood Ants only, tim­ing depend­ent on ambi­ent tem­per­at­ure and levels of sun­shine). In south­ern UK, Wood Ants can emerge as early as Feb­ru­ary, depend­ing on weath­er. Activ­ity of the work­ers begins when the intern­al nest tem­per­at­ure rises to between 25 – 30°C.	Rais­ing queens and males (from eggs laid in late winter/​early spring).

May – Octo­ber	June — August
Gen­er­al work­er activ­ity – for­aging, aph­id farm­ing, repair­ing and build­ing nest. Num­ber of act­ive work­ers involved in for­aging peaks in mid- sum­mer. Size of indi­vidu­al work­ers var­ies greatly with­in the colony and depends on the qual­ity of diet dur­ing the lar­val stage.	Emer­gence of vir­gin queens and males, mat­ing flights take place. This is usu­ally con­fined to a rel­at­ively short win­dow of 2 – 3 weeks. In south­ern Eng­land can be as early as May, in north­ern Scot­land may be as late as July-August

Colony estab­lish­ment and life cycle

1 Mat­ing

Queens and males under­take mat­ing flights. Queens drop their wings soon after mating.

2 Colony establishment

Social para­sit­ism

Estab­lishes a new colony by para­sit­ising the nest of a dif­fer­ent ant species

Mated queen returns to nat­al nest

Nest bud­ding takes place

When there are mul­tiple queens in a single nest

Queen lays eggs

Hatch into larvae

3 Life­cycle of an ant

Queen

Pupate when fully developed – pupae can be cocooned or ​‘naked’.

Male

Work­er

1 Mat­ing

Newly emerged queens and males take to the wing. Males usu­ally emerge first and dis­perse to reduce chances of mat­ing with queens from their own nests. Takes place in the morn­ing on still, warm days.

2 Colony establishment

Social para­sit­ism

A newly mated queen flies from her nat­al nest and estab­lishes a new colony by para­sit­ising the nest of a dif­fer­ent ant spe­cies – in the UK the host spe­cies are Formica fusca, F. lemani and F. cunicu­laria. The Wood Ant queen enters the nest of the host, kills or excludes the queen and then uses the host work­ers to raise her own off­spring. This cre­ates a mixed colony until even­tu­ally the host work­ers die off and only the Wood Ants remain. This meth­od of colony estab­lish­ment is very risky and not always suc­cess­ful. Social para­sit­ism is the only way Nar­row- headed Ant and Blood-red Ant estab­lish new nests.

Mated queen returns to nat­al nest

Wood ant and Nar­row-headed Ant nests can con­tain a single queen (mono­gyny) or mul­tiple queens (poly­gyny). In some parts of their range, nests can be mono­gyn­ous, while in oth­er areas the spe­cies can be poly­gyn­ous. The num­ber of repro­du­cing queens with­in a poly­gyn­ous nest can vary from 2 – 20 in Hairy Wood Ants, or to hun­dreds in Scot­tish Wood Ants. Queens from mono­gyn­ous nests are thought to be bet­ter at long-range dis­pers­al and this strategy can lead to rap­id col­on­isa­tion of new habitats.

Nest bud­ding takes place

Instead of dis­pers­ing, queens can return to their nat­al nest and then estab­lish a new nest by bud­ding. This res­ults in a new nest mound which con­tains work­ers and a queen which is related to the nat­al nest. By form­ing satel­lite nests in this way,

Wood Ants and Nar­row-headed Ants can exist in ​‘super colon­ies’ which com­prise of mul­tiple mounds (known as poly­domy, which means ​‘many homes’). Work­ers mov­ing in between them to exchange resources. Nest bud­ding allows a gradu­al dis­pers­al through a hab­it­at, and allows the colony to be adapt­able to changes in hab­it­at and food resources.

3 Life cycle of an ant

Only queens lay eggs. Eggs hatch into lar­vae and then under­go com­plete meta­morph­os­is to become adult ants. Lar­vae are fed a pro­tein rich diet (insect prey, par­tic­u­larly cater­pil­lars). Work­ers move lar­vae and pupae around the nest to the warmest areas to optim­ise development.

Depend­ing on diet at the lar­val stage and wheth­er the egg has been fer­til­ised, the lar­vae will become one of three adults:

Work­er (fer­til­ised egg)

Work­ers are always female and closely related, being daugh­ters of a queen or queens which them­selves are related. Young work­ers are involved in brood and queen care. As they age, they become involved in nest main­ten­ance and repair. The older work­ers are those that for­age for food away from the nest. Most work­ers live for about a month, though work­ers that over­winter with the queen live for sev­er­al months.

Queen (fer­til­ised egg, spe­cial diet)

Stud­ies sug­gest a single queen can live for over a dec­ade. In poly­gyn­ous nests, queens suc­ceed each oth­er, which allows single nests and colon­ies to sur­vive for sev­er­al decades.

Male (unfer­til­ised egg)

Emerge for only a short peri­od of time to mate and then die shortly after­wards. Queens and males may not be pro­duced every year — only healthy nests are able to sup­port pro­duc­tion of sexu­al stages.

Scot­tish Wood Ant (Formica aqui­lo­nia)

Gen­er­al appearance

Work­er show­ing dis­tinct­ive black-red coloration.

Size and col­or­a­tion var­ies with­in a nest and can­not be used reli­ably for identification.

B A Side view of a work­er when viewed with a x20 hand lens. At least 5 indi­vidu­als should be checked as hairs vary from indi­vidu­al to individual.

Actu­al size of work­ers, show­ing size range

Dia­gnost­ic fea­tures A. Sparse, short hairs around top of head which do not reach the eyes B. Hairs sparse and short along top of thor­ax com­pared to Hairy Wood Ant

There is some evid­ence to sug­gest that Scot­tish Wood Ant can hybrid­ise with Hairy Wood Ant where the two spe­cies occur side by side (Scot­land only in the UK). This means that some colon­ies will have traits of both spe­cies and will be impossible to sep­ar­ate based on mor­pho­lo­gic­al characteristics.

Hairy Wood Ant (Formica lugubris)

C Gen­er­al appearance

Work­er show­ing dis­tinct­ive black-red col­or­a­tion – often appear dark­er com­pared to the oth­er species.

Size and col­or­a­tion var­ies with­in a nest and can­not be used reli­ably for identification.

B A Side view of a work­er when viewed with a x20 hand lens. At least 5 indi­vidu­als should be checked as hairs vary from indi­vidu­al to individual.

Actu­al size of work­ers, show­ing size range

Dia­gnost­ic fea­tures A. Row of short hairs around the top of the head reach­ing the eyes B. Hairs form an almost con­tinu­ous line along the top of the thor­ax to the waist and appear longer than those of South­ern Red Wood Ant and Scot­tish Wood Ant C. Long hairs emer­ging from sides of the thor­ax when viewed from above

There is some evid­ence to sug­gest that Hairy Wood Ant can hybrid­ise with Scot­tish Wood Ant where the two spe­cies occur side by side (Scot­land only in the UK). This means that some colon­ies will have traits of both spe­cies and will be impossible to sep­ar­ate based on mor­pho­lo­gic­al characteristics.

South­ern Red Wood Ant (Formica rufa)

Gen­er­al appearance

Work­er show­ing dis­tinct­ive black-red coloration.

Size and col­or­a­tion var­ies with­in a nest and can­not be used reli­ably for identification.

A B Side view of a work­er when viewed with a x20 hand lens. At least 5 indi­vidu­als should be checked as hairs vary from indi­vidu­al to individual.

Actu­al size of work­ers, show­ing size range

Dia­gnost­ic fea­tures A. Shows (almost entire) absence of hairs around top of head in between the eyes B. Few, short hairs along top of thorax

Blood-red Ant (Formica san­guinea)

Gen­er­al appearance

Work­er show­ing bright­er orange-red col­or­a­tion com­pared to work­ers of Wood Ants — often lar­ger than the work­ers of the oth­er species.

Size var­ies with­in a nest and can­not be used reli­ably for identification.

Face view using a x20 hand lens

Actu­al size of work­ers, show­ing size range

Dia­gnost­ic features

Blood-red Ant show­ing dis­tinct notch in the middle of the clyp­eus or ​‘lip’

Hairy, Scot­tish and South­ern Red Wood Ant show­ing dis­tinct round ​‘lip’ in comparison

This spe­cies is known as a social para­site; queens raid the nests of smal­ler black ant spe­cies (in the UK Formica fusca and Formica lemani), killing the res­id­ent queen and using the work­ers to estab­lish their nest. In estab­lished Blood-red Ant nests, work­ers carry out ​‘raid­ing parties’ and take lar­vae and pupae of F. fusca and F. lemani to rear and boost num­bers of work­ers in their own nest. When small black ants are seen along­side work­ers of the Blood-red Ant this is the res­ult of these mixed spe­cies colonies.

Nar­row-headed Ant (Formica exsecta)

Gen­er­al appearance

Work­er show­ing black-red col­or­a­tion and dis­tinct­ive shape of the head.

Size var­ies, but on aver­age work­ers are smal­ler and appear more ​‘petite’ than the work­ers of Wood Ants and Blood-red Ant.

Actu­al size of work­ers, show­ing size range

Dia­gnost­ic features

Nar­row-headed Ant show­ing ​‘nar­rowed’ face and dis­tinct notch in top of head

This fea­ture can be seen with the naked eye

Wood Ant show­ing wider, roun­ded head in comparison.

Face view using a x20 hand lens

Stew­art Taylor

Shin­ing Guest Ant (Formi­coxenus nitid­u­lus)

Gen­er­al appearance

Very shiny and smooth all over and uni­form in colour.

Tiny size makes it tricky to spot.

Actu­al size of work­ers, show­ing size range

Shin­ing Guest Ant along­side the work­er of the much lar­ger Wood Ant. The Shin­ing Guest Ant is approx­im­ately a quarter of the size of a Wood Ant worker.

The Shin­ing Guest Ant only lives in the nests of Wood Ants and is entirely depend­ent on them. It devel­ops its own nest with­in the thatch of the Wood Ant’s nest and even for­ages along­side them. Due to its tiny size and secret­ive life­style the bio­logy of this spe­cies is not fully understood.

Indi­vidu­als can be observed on the thatch of the Wood Ant nest, usu­ally in small num­bers but some­times tens of indi­vidu­als. In the UK South­ern Red Wood Ant, Hairy Wood Ant and Scot­tish Wood Ant are host species.

It can be con­fused with a related spe­cies – the Slender Ant (Lepto­thor­ax acer­vor­um) which is very sim­il­ar in size and appear­ance see page 14. The Slender Ant is very com­mon and is also occa­sion­ally seen on the sur­face of Wood Ant nests.

Com­par­is­on between Shin­ing Guest Ant and Slender Ant

Slender Ant

Note dark, dull head and dull thor­ax. The head and thor­ax also appear ​‘wrinkly’.

Shin­ing Guest Ant

Very shiny and smooth all over with a smal­ler, paler head than the Slender Ant.

Actu­al size of work­ers, show­ing size range

Actu­al size of work­ers, show­ing size range

Where to find Wood Ants

Spe­cies	UK dis­tri­bu­tion	Where to look
Scot­tish Wood Ant (Formica aqui­lo­nia)	Scot­land and a single site in Armagh in North­ern Ire­land (which may be extinct). In Scot­land has been recor­ded as far north as Ross and Suth­er­land. Extends west and south of this into the west High­lands and Argyll. Skye and Arran are the only Scot­tish islands with records. Less com­mon than Hairy Wood Ant in the east Highlands.	Gen­er­ally in older, closed can­opy wood­land (pine or birch) where nests are usu­ally situ­ated in pock­ets of sun­shine. More tol­er­ant of shade than the oth­er spe­cies. Builds thatched mounds which can reach large size. Nests can con­tain tens of thou­sands of work­ers which can be observed at the nest, the wood­land floor and mov­ing up and down tree trunks.
Hairy Wood Ant (Formica lugubris)	Eng­land, Wales and Scot­land. As far south as Derby­shire. In north­ern Eng­land and Wales this spe­cies over­laps with South­ern Red Wood Ant. In Scot­land found in cent­ral and north­ern Scot­land but not in south­ern Scot­land. Over­laps in range with Scot­tish Wood Ant.	Wide vari­ety – pine and birch wood­land, also heath­land with scattered trees. Nests are usu­ally con­cen­trated along wood­land edges and in clear­ings. Builds thatched mounds which can reach a large size. Nests can con­tain tens of thou­sands of work­ers which can be observed at the nest, the wood­land floor and mov­ing up and down tree trunks.

*There is ongo­ing research into the genet­ics of Formica rufa in the UK as there is evid­ence that the ants believed to be Formica rufa may actu­ally be a hybrid between Formica rufa and anoth­er Wood Ant, Formica polyc­tena. Until this work is com­pleted, to avoid con­fu­sion, this guide is refer­ring to this spe­cies as Formica rufa.

Spe­cies	UK dis­tri­bu­tion	Where to look
South­ern Red Wood Ant (Formica rufa)*	Eng­land and Wales. Evid­ence that this spe­cies is con­tract­ing in range in the north, cent­ral, and east­ern parts of its range. Most com­mon in the south and south-east of Eng­land but may be under-recor­ded in oth­er areas.	Wide vari­ety — pine, oak and birch wood­land, also heath­land with scattered trees. Requires open sunny loc­a­tions with some shel­ter. Builds thatched mounds that can reach a large size. Nests can con­tain tens of thou­sands of work­ers which can be observed at the nest, the wood­land floor and mov­ing up and down tree trunks.
Blood-red Ant (Formica san­guinea)	Eng­land, Wales and Scot­land. In Scot­land, con­cen­trated in cent­ral and east­ern areas (High­lands, Aber­deen­shire and Moray). In Eng­land found in the south only. In Wales there are only scattered records in bor­der counties. Likely to be under-recorded.	Pre­dom­in­antly con­i­fer­ous wood­land. Favours open, south-facing hab­it­at. Usu­ally nests in dead wood — trees that are dry and fri­able. Can also nest in bare ground and under stones. A thatched area is usu­ally present but rarely forms a free-stand­ing dome. Often uses past clear-fell sites but can also be found in small open pock­ets in wood­land where there are dead trees. Always open, sunny sites, mov­ing quickly to altern­at­ive loc­a­tions when nest sites become shaded. Largest ant in the UK, with orange-red appear­ance. Not as dark in appear­ance as the Wood Ants. Work­ers are fren­et­ic in their activ­ity and usu­ally choose to bite rather than spray form­ic acid if threatened.

	UK dis­tri­bu­tion	Where to look
Nar­row- headed Ant (Formica exsecta)	Eng­land and Scot­land. Two dis­tinct pop­u­la­tions in Scot­land: one pop­u­la­tion in the Cairngorms Nation­al Park with a tiny outly­ing pop­u­la­tion in Perth­shire. In Eng­land found in one area in Devon only.	Always open, sunny hab­it­ats: heath­land bor­der­ing wood­land, old wood­land with large glades, even bog wood­land. Inhab­its both pine and birch wood­land. Builds a thatched mound with fine mater­i­als such as grasses, heath­ers and dried moss. Nests typ­ic­ally half a foot­ball in size. A few nests found in Scot­land reach Im across. Nests con­tain smal­ler num­ber of work­ers than that of Wood Ants. Has a more pain­ful bite than the Wood Ants due to the large jaw muscles (which give the ant its dis­tinct­ive shaped-head).
Shin­ing Guest Ant (Formi­coxenus nitid­u­lus)	Eng­land and Scot­land. Scattered records from the regions where its hosts occur. As yet unknown from Wales, North­ern Ire­land and Chan­nel Islands. Likely to be under-recorded.	Asso­ci­ated with South­ern Red, Hairy and Scot­tish Wood Ants in the UK. Not found in all host nests — it is thought to only inhab­it Wood Ant nests that are in a healthy con­di­tion. Septem­ber and Octo­ber is best time to observe this spe­cies. Queens and males are work­er-like in appearance.

Nest mounds

Jenni Stockan Scot­tish Wood Ant Large thatched mound, often has a domed appearance.

Hay­ley Wiswell Blood-red Ant ​‘scruffy’ thatch, often built around dried out tree stumps

Jenni Stockan Hairy Wood Ant Large thatched mound, often has a flat topped appearance.

Jenni Stockan Nar­row- headed Ant Usu­ally smal­ler than Wood Ant nests with a pale, grassy appear­ance, often made from much finer material.

N.A.Robinson South­ern Red Wood Ant Large thatched mound, often built around a rock or tree stump.

Shin­ing Guest Ant Only lives in the nests of Wood Ants and is entirely depend­ent on them. It devel­ops its own nest with­in the thatch of the Wood Ant’s nest.

Spe­cies distributions

The maps show vice counties where the spe­cies occur, not pre­cise dis­tri­bu­tions. Based on records from 1980 onwards, using pub­lic records from the Nation­al Biod­iversity Net­work atlas.

North­ern Ire­land is not included on the maps there is only a single pop­u­la­tion of Scot­tish Wood Ant in Armagh and this is the only record.

Scot­tish Wood Ant (Formica aqui­lo­nia)

Hairy Wood Ant (Formica lugubris)

South­ern Red Wood Ant (Formica rufa)

Blood-red Ant (Formica san­guinea)

Nar­row-headed Ant (Formica exsecta)

Shin­ing Guest Ant (Formi­coxenus nitid­u­lus)

Hay­ley Wiswell

Man­aging hab­it­at for wood ants

Wood Ants are not leg­ally pro­tec­ted. How­ever some of the spe­cies are of con­ser­va­tion con­cern and are lis­ted as pri­or­ity species.

* Pub­lic bod­ies have a duty to take neces­sary steps to con­serve biod­iversity and this includes all wild­life, not just those sites and spe­cies which are protected.

It is con­sidered good prac­tice to avoid delib­er­ately harm­ing Wood Ants and their nests, par­tic­u­larly in light of their import­ant roles with­in wood­land ecosystems.

Shin­ing Guest Ant is depend­ent upon Wood Ants for its exist­ence. Its list­ing as a pri­or­ity spe­cies in Eng­land and Scot­land there­fore implies pri­or­ity status to its UK host spe­cies: South­ern Red Wood Ant, Hairy Wood Ant and Scot­tish Wood Ant. See page 27 for an over­view of the con­ser­va­tion status of each species.

As well as inhab­it­ing semi-nat­ur­al wood­land hab­it­ats Hairy Wood Ant, Scot­tish Wood Ant, South­ern Red Wood Ant and the Blood-red Ant can all occur in forests man­aged for com­mer­cial purposes.

The Nar­row-headed Ant can exist on open moor­land hab­it­at sub­ject to graz­ing or burn­ing as long as there are some scattered trees for foraging.

Wood Ants and their related spe­cies need rel­at­ively large hab­it­at patches of well con­nec­ted hab­it­at with stable food resources in order for colon­ies to flour­ish. Cohes­ive man­age­ment sens­it­ive to the needs of these spe­cies is required across large areas to cre­ate a land­scape where these spe­cies can thrive.

Mosa­ics of wood­land hab­it­at, from young scattered trees to mature wood­land will bene­fit dif­fer­ent spe­cies of ants. Com­mer­cial forestry can be bene­fi­cial to these spe­cies if planned and man­aged in a way sens­it­ive to their needs.

* Nat­ur­al Envir­on­ment and Rur­al Com­munit­ies Act (2006) in Eng­land and Wales, Nature Con­ser­va­tion (Scot­land) Act (2004), and Wild­life and Nat­ur­al Envir­on­ment Act (North­ern Ire­land) 2011

Below are guid­ing prin­ciples to fol­low when under­tak­ing man­age­ment in hab­it­ats that sup­port the spe­cies in this guide:

• Tra­di­tion­al sil­vi­cul­tur­al meth­ods using a shel­ter­wood sys­tem are more sens­it­ive to the needs of ants — i.e. thin­ning rather than clear-felling. Remov­ing large num­bers of trees removes aph­ids, prey resource and changes the micro­cli­mate (essen­tial for rear­ing brood). Clear- felling, if required, should only be done in small coups and should avoid areas with large num­bers of nests. Sur­viv­al of nests in clear-fell areas is improved when nests are loc­ated close to forest edges

• To pro­tect nests from dir­ect dam­age dur­ing forestry man­age­ment, it is good prac­tice to record and clearly mark nests pri­or to felling. Make con­tract­ors aware of the pres­ence of nests so that they can be avoided by machinery

• Hab­it­at con­nectiv­ity is import­ant to allow Wood Ants to dis­perse through the land­scape. Blocks of wood­land should be no more than 200m apart (this is thought to be the max­im­um dis­tance that nests can ​‘bud’)

• Scal­loped edges on wood­land bound­ar­ies, rides and track-sides facing south and south-east cre­ates more hab­it­at com­pared to straight edges

• Pheas­ants are likely to pred­ate on ants so it is not advis­able to intro­duce pheas­ants and part­ridges into wood­land where there are nests

• Low graz­ing levels can become an issue for the par­tic­u­larly heat- depend­ent spe­cies (South­ern Red Wood Ant, Blood-Red Ant and Nar­row-Headed Ant) where hab­it­at suc­ces­sion can res­ult in shad­ing of nests. How­ever low graz­ing levels are needed in oth­er areas to allow tree regen­er­a­tion so that these wood­land depend­ent spe­cies can dis­perse across the landscape

• Cre­at­ing mosa­ics of hab­it­at from mature wood­land to scattered trees and open heath­ery and grassy glades will bene­fit a wider range of spe­cies. Scot­tish Wood Ant is more suited to long-ter­m/per­man­ent wood­land while Hairy Wood Ant and Blood-Red Ant can bene­fit from forest rejuvenation

• Muir burn of moor­land should be avoided where there is risk of dir­ectly dam­aging ant colonies

• Trans­lo­ca­tion of Wood Ant nests should not be under­taken lightly and should only be done as a last resort where dam­age to nests is unavoid­able or pop­u­la­tions are at risk of extinc­tion. There is also scope to trans­lo­cate Wood Ant nests when rein­tro­du­cing key­stone spe­cies into unoc­cu­pied hab­it­at but this requires care­ful consideration.

Jenni Stockan Com­mer­cial forestry can provide good hab­it­at for Wood Ants, or it can cre­ate unsuit­able hab­it­at and even frag­ment pop­u­la­tions. Here a nest of the Scot­tish Wood Ant is sur­roun­ded by dense Sitka Spruce plant­a­tion, likely planted on a site which was form­ally nat­ive wood­land — the nest is asso­ci­ated with an old Scots Pine which stood before the spruce was planted. This nest is able to sur­vive because a clear­ing con­tain­ing the pine tree has been retained, but the sur­round­ing spruce is too dense to be suit­able for the ants to use. Wood Ants are often strongly asso­ci­ated with semi- nat­ur­al wood­land but can quickly spread into planted wood­land where it meets their needs: close enough for exist­ing Wood Ant pop­u­la­tions to dis­perse into, some open­ings in the can­opy to provide sun­light for nests and not over grazed so that a healthy ground cov­er develops.

Sur­vey tech­niques and monitoring

Depend­ing on the size of an area to be sur­veyed and the resources avail­able, there are two sur­vey options:

1 Aim to record all of the nests in an area

With a team of sur­vey­ors, a wood­land can be sur­veyed by work­ing across the hab­it­at in a line, each sur­vey­or spaced about 5m. One sur­vey­or uses a com­pass to dir­ect the team along a bear­ing. The line of sur­vey­ors stops each time someone finds a nest and then resumes once a record of the nest is made.

2 Take a sample by using a focused transect

A single sur­vey­or walks a fixed tran­sect through a chosen area and records nests along the tran­sect and with­in a fixed buf­fer either side (say 5m) of the tran­sect. The tran­sect can cross through dif­fer­ent hab­it­at types to com­pare nest densities/​loc­a­tions in dif­fer­ent areas.

Look­ing for Shin­ing Guest Ants

The most reli­able and least destruct­ive way to find Shin­ing Guest Ant is to sit beside a Wood Ant nest and simply observe the thatch. Shin­ing Guest Ants are more obvi­ous at par­tic­u­lar times of year the ideal time is Septem­ber and Octo­ber when males come to the sur­face (though they have been observed as early as June). Since Wood Ants are some­times less act­ive at this time, any Shin­ing Guest Ants on the sur­face can be easi­er to spot. For the same reas­on, observing a nest in the morn­ing, par­tic­u­larly on a cool­er, over­cast day when Wood Ant work­ers are less likely to be act­ive is usu­ally more productive.

Mon­it­or­ing

As well as search­ing for nests and record­ing their dis­tri­bu­tion, it is use­ful to repeatedly vis­it the same areas where Wood Ants live in order to record how they change over time, par­tic­u­larly if they are in a wood­land that is act­ively man­aged. Mon­it­or­ing can simply involve repeat­ing a sur­vey along a fixed tran­sect every 3 – 5 years. Mon­it­or­ing the before and after phases of hab­it­at man­age­ment, such as forest thin­ning or wood­land plant­ing can be par­tic­u­larly use­ful for assess­ing the impact, pos­it­ive or neg­at­ive, on Wood Ants and their related species.

Record­ing Wood Ants

It is import­ant to record the fol­low­ing inform­a­tion when you have found a Wood Ant nest:

• Spe­cies (see below)

• A grid ref­er­ence using the UK Nation­al Grid (10 fig­ure grid ref­er­ence is best)

• Date

• Loc­a­tion or site

• The name of who is mak­ing the record.

For the iden­ti­fic­a­tion you will need:

Ross John­ston 20x hand lens To dis­tin­guish the spe­cies in this guide, some prac­tice is needed!

At least 5 spe­ci­mens per nest Indi­vidu­als can vary and work­ers often lose their hairs as they age.

Records of spe­cies will nor­mally only be accep­ted when checked by an expert. If the spe­cies is not known, a grid ref­er­ence of the nest togeth­er with a pho­to­graph is still very use­ful. Records of absence are also valuable.

If you have found a nest, use the fol­low­ing to sub­mit your record:

i‑Naturalist

www​.uk​.inat​ur​al​ist​.org

Con­nects with a com­munity of over a mil­lion sci­ent­ists and nat­ur­al­ists. By record­ing and shar­ing your obser­va­tions you’ll cre­ate research qual­ity data for sci­ent­ists work­ing to bet­ter under­stand and pro­tect nature.

iRe­cord

www​.brc​.ac​.uk/​i​r​e​cord/

Inspect­ing a Wood Ant work­er through a hand lens

Please Note:

Ants defend their nests aggress­ively – ants can bite if handled and also spray form­ic acid as a deterrent, so beware of this when observing nests and hand­ling work­ers. It’s import­ant not to dis­turb the thatch of the nest — although wood ants are very good at repair­ing their nests, this requires addi­tion­al resources and if dam­aged over winter, can expose the ants to harsh weather.

Con­ser­va­tion status of Wood Ants

Scot­tish Wood Ant

• IUCN status: ​“Near Threatened” (last assessed 1996)

• North­ern Ire­land Pri­or­ity Spe­cies (Wild­life and Nat­ur­al Envir­on­ment Act (North­ern Ire­land) 2011)

• Sub­ject to an action plan in the Cairngorms Nation­al Park (2019−2024)

Hairy Wood Ant

• IUCN status: ​“Near Threatened” (last assessed 1996)

• Sub­ject to an action plan in the Cairngorms Nation­al Park (2019−2024)

South­ern Red Wood Ant

• IUCN status: ​“Near Threatened” (last assessed 1996)

• Included in some Loc­al Biod­iversity Action Plans in Eng­land (check your loc­al author­ity area).

Blood-red Ant

• IUCN status: Not assessed

• Sub­ject to an action plan in the Cairngorms Nation­al Park (2019−2024)

Nar­row-headed Ant

• GB Red List: ​“Endangered”

• Nat­ur­al Envir­on­ment & Rur­al Com­munit­ies Act (2006) Sec­tion 41 (Eng­land) – lis­ted under ​“Spe­cies of Prin­ciple Importance”

• Nature Con­ser­va­tion (Scot­land) Act 2004 — lis­ted as a pri­or­ity spe­cies on the Scot­tish Biod­iversity List under the cat­egor­ies ​“Con­ser­va­tion Action Needed” and ​“Avoid Neg­at­ive Impacts”

• Sub­ject to an action plan in the Cairngorms Nation­al Park (2019−2024)

• Sub­ject to an action plan under Devon Loc­al Nature Partnership

The Shin­ing Guest Ant

• IUCN status: ​“Vul­ner­able” (last assessed 1996)

• Nat­ur­al Envir­on­ment & Rur­al Com­munit­ies Act (2006) Sec­tion 41 (Eng­land) – lis­ted under ​“Spe­cies of Prin­ciple Importance”

• Nature Con­ser­va­tion (Scot­land) Act 2004 – lis­ted as a pri­or­ity spe­cies on the Scot­tish Biod­iversity List under the cat­egory ​“Watch­ing Brief Only”

• Sub­ject to an action plan in the Cairngorms Nation­al Park (2019−2024)

Fur­ther information

For more inform­a­tion visit

www​.wood​ants​.org​.uk

Digit­al cop­ies of this guide and guid­ance on trans­lo­ca­tion of Wood Ant nests can be found at this website.

Use­ful resources:

• Stockan, J. & Robin­son, E. (Eds.). (2016). Wood Ant Eco­logy and Con­ser­va­tion (Eco­logy, Biod­iversity and Con­ser­va­tion). Cam­bridge: Cam­bridge Uni­ver­sity Press

• Mac­don­ald, M. (2013). High­land Ants: Dis­tri­bu­tion, Eco­logy and Con­ser­va­tion. High­land Bio­lo­gic­al Record­ing Group. Can be down­loaded free from: www​.hbrg​.org​.uk/​A​n​t​A​t​l​a​s​/​D​o​w​n​l​o​a​d​A​n​t​A​t​l​a​s​.html

• Skin­ner, G. J. & Allen G.W. (2015) Nat­ur­al­ists Hand­books 24: Ants. Pela­gic pub­lish­ing (due to be updated in 2021)

• AntWiki www​.antwiki​.org/wiki

• Brit­ish Wasps and Ants Record­ing Soci­ety www​.bwars​.com

Acknow­ledge­ments

CLIF Nation­al Parks Protectors

Thanks to CLIF for their sup­port of Nation­al Parks Pro­tect­ors through which this pub­lic­a­tion was funded.

Thanks to Elva Robin­son and Josie Mon­aghan (Uni­ver­sity of York) for their advice and sup­port in the pro­duc­tion of this guide.

Thanks to Jenni Stockan, Joan Beaton and Stew­art Taylor for the use of their photographs.

Illus­tra­tions Liz­zie Harp­er – www​.liz​zieharp​er​.co​.uk

Text Hay­ley Wiswell

Scot­tish Wood Ant Joan Beaton

CAIRNGORMS NATION­AL PARK AUTHOR­ITY ÙGH­DAR­RAS PÀIRC NÀISEANTA Α’ MHON­AIDH RUAIDH

Pub­lished by the Cairngorms Nation­al Park Authority

Con­tact us Cairngorms Nation­al Park Author­ity 14 The Square, Grant­own-on-Spey PH26 3HG @ enquiries@​cairngorms.​co.​uk 01479 873535 www​.cairngorms​.co​.uk

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