Dung Beetles

Dung Beetles

1 Introduction

Dung beetles are insects that feed partly or exclusively on animal faeces. Some species of dung beetles,
known as rollers (teleocoprids), roll dung into round balls which are used as a food source; others, known
as tunnelers (paracoprids), bury the dung where they find it, and a third group, the dwellers
(endocoprids), neither roll nor burrow: they simply live within the manure. Dung beetleS come in many
different colours and sizes, and some functional traits such as body mass and leg length can have high
levels of variability. Dung beetles are found on all continents except Antarctica and live in many
habitats, including desert, grasslands and savannas, farmlands, and native and planted forests. They
are highly influenced by the environmental context, and do not prefer extremely cold or dry weather.
They eat the dung of herbivores and omnivores and prefer that produced by the latter and do not
need to eat or drink anything else because the dung provides all the necessary nutrients.

All the species belong to the superfamily Scarabaeoidea, most of them to the subfamilies
Scarabaeinae and Aphodiinae of the family Scarabaeidae (Scarab Beetles). As most species of
Scarabaeinae feed exclusively on fAeces, that subfamily is often referred to as ‘True Dung Beetles’.
There are dung-feeding beetles which belong to other families, such as the Geotrupidae (the earth-
boring dung beetleS). The Scarabaeinae alone comprises more than 5,000 species. The UK has more
than 40 native species of dung beetles. By tunneling and breeding within dung, feeding upon it and
burying it below ground, dung beetles break down and decompose our animal waste, releasing vital
nutrients for plant growth. Dung Beetles provide ‘ecosystem services’ to the UK cattle industry valued at
over £367 million per anum (Dung beetles direct Factsheet 1). They also fertilise and aerate soils and
may control livestock parasite burdens on pastures (Dung beetles direct FactSheet 2).

Unfortunately, some worming and other parasite control treatments (parasiticides) are toxic to dung
beetles and routine treatment of stock with these chemicals can have a negative impact on dung
beetles and other soil invertebrates. For this reason, as well as to minimise the build-up of resistance to
these drugs, a parasite control plan was introduced to the farm management on Bardsey Island in 2016.
As part of this plan, Faecal Egg Counts (FEC) are used to determine the appropriate timing and type of
worming drug.

The FEC tests have been a helpful addition to stock management on Bardsey, reducing the number of
chemical worming treatments and enabling the choice of worming drugs that are at the lower end of
toxicity to soil invertebrates.

Bardsey is an important and well documented breeding and foraging site for Choughs Pyrrhocorax
pyrrhocorax, a species of European importance. Soil invertebrates, including dung beetles and their
larvae, are an important component of the Chough’s diet. A study undertaken on Bardsey in 1982
(Roberts, 1982) found that the diet of Choughs feeding on the island was quite varied, being composed
of beetles (Aphodius), weevils (Curculionidae), click beetles (Elateridae), ants (Formicoidea), craneflies
(Tipulidae), Swift moth caterpillars (Hepialus), European Earwigs Forficula auricularia, St. Mark's fly (Bibio
marci and B. laniger), Kelp fly Coelopa frigida, sandhoppers Orchestia gammarella (Crustacea), spiders
and harvestmen. Beetles as a whole seemed to be a very important food source for Choughs on Bardsey
for most of the year, especially in spring and autumn. In the survey by Roberts, 50-100% frequency was
noted in faeces from late April to the end of June, in the first half of August, and during September and
October.

The last survey to specifically look at the dung beetle species and abundance on Bardsey was in 1985
by Prof. R.G. Loxton. He was particularly interested in comparing the number of genera and species
present with those on the nearby mainland. He collected species from sheep and horse dung
throughout the season and from different habitats. Only one genus (Aphodius) was found on Bardsey
during the survey, of which seven species were identified. He particularly noted the absence of
Aphodius fimetarius, which had last been recorded on the island in 1967. He suggested that its apparent

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recent extinction was due to the withdrawal of cattle from the island in 1972, as this species favours
cattle dung.

Cattle were returned to the island in 1996 and have been present year-round since then. However, in
late 2017 the cattle were taken off the island for the winter months. In the past decade the cattle have
been over-wintered on the Mountain, with the objective being gorse and bracken control to benefit
heathland management. This has been of limited success and so the cattle will be taken off the island
for the winter in 2017, to be returned to graze the Mountain in spring and summer in 2018 when they will
hopefully have more success in bracken and gorse control. This will, therefore, be the first break in the
presence of cattle on the island for over 20 years.

2 Aims

The aims of this study were to:

• record an inventory of dung beetle species on Bardsey prior to the cattle’s departure
• to compare 2017 with the 1985 species list and create a current species baseline
• to continue monitoring the dung beetle population throughout the change in grazing regime

3 Methods

Jo Porter undertook the fieldwork for this study and investigated random samples of cattle and sheep
dung beetles once a month from April to October. The visual search method used is detailed in DUMP,
the Dung beetle UK Mapping Project, which is hosted by the Oxford University Museum of Natural
History:

This simply involves finding a pile of dung and breaking it apart to look inside and find
the beetles. Also look for tunnels at the soil interface under the dung. These can be
large enough to poke in your thumb (Geotrupidae tunnel) or as small as the width of
a pencil (Onthophagus similis, Colobopterus erraticus). The beetle can be very
carefully dug out with a small trowel. Often the best approach is to feel the direction
of the tunnel by poking in a finger, then place a ‘marker’ such as a pea stick in the
tunnel and dig from one side as tunnels can easily collapse.

All the beetles found in/around/underneath a cowpat were collected for identification. The different
species were photographed and preserved for identification confirmation.

The most frequent dung inhabited by dung beetles tended to be 2-3 week-old cowpats and sheep
dung. This determined the locations from which the samples were taken, although samples were taken
from a variety of habitats.

The number of individuals collected was not recorded, nor was the area of the island they were found
in, so we are unable to make quantifiable estimates of the species’ abundance and specific
distribution, however, this is something that we would like to see undertaken in the near future.

All photograhs © Ben Porter – All are Bardsey specimens collected in 2017

294 Rep. Bardsey Bird Fld Obs

Dung Beetles

4 Results

The systematic list below gives a brief summary of the species’ status in the UK and, where relevant, the
records on Bardsey pre-2017, along with a table showing the phenological distribution during 2017 in
each type of dung. The scale lines are approximate ( 20%).

Scarabaeidae

Aphodius ater (Degeer, 1774)
A small (4-6 mm) common species found
throughout England, Wales and Scotland. It is found
in various types of dung as well as decaying
vegetable matter. Adults appear slightly later than
other spring species; they are then found
continuously until autumn.

This species was previously recorded on the island 5 mm
by Askew in 1974 and Loxton in 1977 and 1985 when
it was found to be frequent in sheep dung,
particularly on the Mountain. In 1999 Loxton found it
to be very common.

It was found in both sheep and cattle dung in 2017
from April to July.

AM J J A S O
Cattle
Sheep

Aphodius contaminatus (Herbst, 1973)
A small (5-7 mm) late summer and autumnal species
found throughout England, Scotland and Wales in
various types of dung. From late August this may
become the most common species, and sometimes
the only species, with each dung sample containing
many hundreds. Disturbing dung can attract adults
in swarms, especially so on hot days.

This species was previously recorded on Bardsey in 6 mm
1982 and 1985 surveys and then by P. Hope-Jones in
1992. This species was said to have been very
numerous on Bardsey, but in the autumn of 1985
only moderate numbers were present.

The species was discovered only in cattle dung and
only during September in 2017. Its abundance was
not recorded, however.

AM J J A S O
Cattle
Sheep

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Porter, Porter and Stansfield 7 mm
10 mm
Aphodius fimetarius (Linnaeus, 1758)
This small (5-8 mm) species is common throughout
the UK in various types of dung and decaying
vegetable matter. Found throughout the year,
sometimes in winter flood refuse, but most
abundant in dung from April and then found
throughout the summer.

This species was previously recorded by Kidd in
1935, then in 1957 and 1958 and then by Morgan
in 1967. The species was obviously common in the
1950s and 1960s, but was not found by Loxton in
1978 or 1985 and was considered extinct following
the removal of cattle in 1972. However, Loxton did
record the species in April 1999, shortly after cattle
had been re-introduced to the island.

In 2017 it was found from June to October, though
none in August.

AM J J A S O
Cattle
Sheep

Aphodius fossor (Linnaeus, 1758)
A medium-sized (9-12 mm) beetle which is
common over much of England and Wales,
though less so northwards and in southern
Scotland. Found usually in horse and cattle dung
from March to October and among food refuse
throughout the autumn and winter.

This species was first recorded in June and August
1999 (Loxton, 2000), with two beetles found in June
and 13 in August. The species was not found in
extensive sampling in 1985, but was common in
cow dung on the mainland.

This species was recorded in cowpats in
September 2017, so it may well have colonized
since the re-introduction of cattle.

AM J J A S O
Cattle
Sheep

296 Rep. Bardsey Bird Fld Obs

Aphodius granarius (Linnaeus, 1767) Dung Beetles
A very small (3-5 mm) beetle that is found across
southern England and a few (c30) sites in Wales; 4 mm
becoming scarcer in the north, its distribution is
widespread, but local. Absent from Scotland. 5 mm
Found in all types of dung and wet decaying
vegetable matter, also under debris in muddy 297
situations. A spring species with adults active in
March, April and May, but also among winter flood
refuse. It is a very cosmopolitan species that has
spread widely around the world.

Previously recorded in 1977 and 1985, but not in
1999 when it was looked for, Loxton (2000)
suggested it may be extinct on Bardsey. It was only
found in sheep dung on the soil near Solfach
previously.

In 2017 specimens were collected from cattle
dung in April.

AM J J A S O
Cattle
Sheep

Aphodius ictericus (Laicharting, 1781)
This is another small (3.5-5 mm) species, that is
classed as Nationally Scarce in the UK, however, it
is likely to be under-recorded in the UK, but within
some well-recorded areas of the region a decline
is indicated. For example, it was recorded from 19
hectads in south-east England before 1990 and
only ten since 1990. It is found in dry sandy areas
mainly on the coast. Up to 2000 there were only five
other known sites in Wales, none of which were
recent.

Previously recorded on Bardsey by Askew in 1974,
and Loxton in 1977 and 1985. In 2017 it was
recorded in cattle dung in April only.

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Cattle
Sheep

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Aphodius pedellus (De Geer, 1774) 6 mm
The British status of this small (5-8 mm) beetle is unclear
as the species was split by Wilson (2001) from
Aphodius fimetarius into two species, A. fimetarius
(Linnaeus) and A. pedellus (De Geer). As a result of
this split it is difficult to assign previous records
between A. pedellus and A. fimetarius. As A.
fimetarius was considered common in the 1950s and
1960s, it is quite probable that this species was
previously overlooked before its split.

In 2017 the first documented records for Bardsey
came from cowpats in April.

AM J J A S O
Cattle
Sheep

Aphodius prodromus (Brahm, 1790)
This is another small (4-7 mm) beetle which is common
and often very abundant across the UK from February
to June and again from September to November. The
species is found throughout England, Wales and
Scotland in a variety of types of dung.

While Jessop (1986) states that it is rarely found in cow 6 mm
dung, the only records from Bardsey in April 2017 were
in cowpats. This species was not discovered in any of
the previous surveys.

AM J J A S O
Cattle
Sheep

Aphodius rufipes (Linnaeus, 1758)
This is a medium to large (9-13 mm) shiny dark brown
beetle which lives mainly in fresh cow dung and is very
common throughout the British Isles. Adults fly at night
and readily come to light.

Previously recorded on Bardsey by Kidd in 1935, 11 mm
Morgan in 1967, and Loxton in 1985 and 1999 mainly in
cow dung.

In 2017 it was found in both cow and sheep dung in
July and August.

AM J J A S O Rep. Bardsey Bird Fld Obs
Cattle
Sheep

298

Aphodius rufus (Linnaeus, 1758) Dung Beetles
This small (5-8mm) beetle is a late summer/autumn
species seen from July to early October. Its status 6 mm
in the UK is said to be locally frequent throughout
England and in some areas of Wales and 4 mm
Scotland. 5 mm

This species was found in sheep dung in August 299
1999 (Loxton 2000). This is another species which
appears to have colonized the island since the
intensive survey of Loxton in 1985. In 2017 it was
recorded from cattle and sheep dung in July and
August.

AM J J A S O
Cattle
Sheep

Aphodius sticticus (Panzer, 1798)
Another small (3.5-5.5 mm) beetle that is locally
common across southern England and into Wales,
becoming scarcer further north to Yorkshire. This
species is most numerous in spring and found in
various dung types.

This species has not been recorded on the island
before the records in sheep dung in April 2017.

AM J J A S O
Cattle
Sheep

Aphodius sphacelatus (Panzer, 1798)
A small (4-6 mm) species, widespread and
common throughout England, Wales and Scotland
in various types of herbivorous dung, and in
decaying vegetable matter and decaying fruiting
fungi. Very often found (in dung) with Aphodius
prodromus (Brahm) with which it may be confused.

Previously recorded by Nye in 1957 and Loxton in
1985 and again in 1999. Loxton found this to be
very abundant in 1985. In 2017 it was found in
sheep and cow dung in April, and sheep dung in
May.

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Sheep

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Geotrupidae

Geotrupes spiniger (Marsham, 1802) 20 mm
This is a big (15-25 mm) black and slightly lustrous
dung beetle that is very similar to Geotrupes
stercorarius, but G. spiniger has a distinct lobe on
the outer edge of the mandible. It is found from
May to October and its larvae live in the dung of
herbivores. It is widespread and fairly frequent
across most of Britain.

There is a single previous record from Bardsey by
Kidd in 1935. It was again found in 2017 in cattle
dung in July.

AM J J A S O
Cattle
Sheep

5 Species recorded in previous years but not in 2017

Scarabaeidae

Aphodious merdarius (Fabricius, 1775)
This small (3-5 mm) scarab beetle was recorded by Roberts in 1982 and by Loxton in 1985 (Loxton, 2000).
Only two insects were found on the Mountain in sheep dung in 1985. It is a widespread but local species
that may be declining (Jessop 1986).

Geotrupidae

Typhaeus typhoeus (Linnaeus, 1758) Minotaur Beetle

The Minotaur Beetle is in impressive large glossy black dung-rolling beetle, with ridges running down the

wing cases. Males are unmistakeable, sporting three forward-projecting 'horns' (two long and one short

one in the centre) on their pronotum. The female lacks the horns but has a sharp tubercle at each

anterior angle of the pronotum. The species is local in England and Wales, becoming scarce further north

and is very rare in Scotland.

Minotaurs were recorded by Darlington (1955), Roberts 1978, Heaver (1984) and Loxton in 1985 and 1986.
More recently there were records from the North End of the island by R.J. Else and R.D. Brown (pers.
comm.).

Geotrupes stercorarius (Linnaeus, 1758)
This is a very large shiny blue/violet-black dung beetle that was first recorded as being ‘very much in
evidence’ by Darlington in 1955, and several times since, including Loxton in 1977 and 1985. This beetle
is a widespread and common species in the UK. It often causes problems for ringers who encounter them
in the mistnets at dusk on Bardsey, sometimes in large numbers.

Anoplotrupes (Geotrupes) stercorosus (Hartmann in Scriba, 1791)
The adults of Anoplotrupes (Geotrupes) stercorosus can grow up to 20 mm in length and therefore they
do not reach the size of the similar species Geotrupes stercorarius. The body is blue-black, while the

300 Rep. Bardsey Bird Fld Obs

Dung Beetles

underside is metallic blue. This is another widespread species, most common in sheep dung in the
uplands of the north and west of Britain. On Bardsey it was recorded by Kidd in 1953, Askew in 1974 and
Loxton in 1985.

6 Discussion

All seven of the Aphodius species documented by Loxton (1986) were found in 2017. Two species which
have been recorded since Loxton’s survey were also found in 2017: A. fossor and A. rufus, both of which
were found in 1999 (Loxton, 2000). Additionally, three new species were found: A. pedellus, A. prodromus
and A. sticticus. Only one species of Geotrupes was found in 2017: G. spiniger.

This gives a total of 12 Aphodius species, and three species of the genus Geotrupes. It would appear
that the island habitats, and the continuous presence of dung, have favoured the colonisation of an
increased variety of dung beetles since the last study in 1985.

Loxton (1986) comments that the species of Aphodius are well adapted to colonisation: the females
mate before dispersal (which is unusual in insects) so that a single female is potentially a coloniser. Also,
these insects are capable of extended flight and can move several miles when dispersing. Bardsey is
only 3km from the nearest point on the mainland and is therefore well within the dispersal range of all
the species.

Roberts (1982) states that most beetles overwinter as larvae, and are then taken in abundance by
Choughs when they emerge in the spring. The question remains as to whether some of these species
with a preference for cow dung will persist during a break of five months without fresh cow dung.
Continued monitoring will hopefully provide an insight into some of these questions.

7 Acknowledgements

Thanks to Darren Mann from DUMP for help with identification of specimens.

8 References

Askew, R.R. 1974. Insects from Bardsey Island. Entomologist’s Gazette, 25, 45-51.
Darlington, A. 1955. Ecological notes on some insects of Bardsey during August 1954. Rep. Bardsey Bird

Fld. Obs., 2,35-38.
Heaver, D.J. 1986. The diet of the Little Owl on Ynys Enlli. Rep. Bardsey Bird Fld. Obs., 29,81-95.
Jessop, L. 1986. Dung Beetles and Chafers. Coleoptera: Scarabaeoidea (New Edition). Handbooks for

the Identification of British Insects 5, 1–53.
Loxton, R.G. 1986. Ynys Enlli dung beetles of the genera Colobopterus, Aphodius and Onthophagus; a

comparison with the mainland fauna. Rep. Bardsey Bird Fld. Obs., 30,105-115.
Loxton, R.G. 2000. An annotated list of the freshwater and terrestrial invertebrates of Bardsey. Bardsey

Bird Observatory.
Roberts P.J. 1982. Foods of the Chough on Bardsey Island, Wales. Bird Study, 29,155-161.
Wilson, C.J. 2001. Aphodius pedellus (DeGeer), a species distinct from A. fimetarius (Linnaeus)

(Coleoptera: Aphodiidae). Tijdschrift voor entomologie, 144, 137–144.
Dung Beetles Direct Factsheet 1 available at:

http://www.drbeynonsbugfarm.com/CMSDocuments//Fact%20sheet%201_Dung%20Beetles_
Aug%202016.pdf
Dung Beetles Direct Factsheets available at:
http://www.drbeynonsbugfarm.com/CMSDocuments//Fact%20sheet%202_Parasiticides_Aug
%202016.pdf

Dung beetle UK Mapping Project- Find, Identify and Record Dung Beetles available at:
https://dungbeetlemap.wordpress.com/finding-and-recording-dung-beetles/

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