Deal or no deal

Melinopterus

by Darren Mann, Head of Life Collections

In a previous article on this blog I reported the discovery, in an insect collection, of the 21st British specimen of the ‘Regionally Extinct dung beetle Melinopterus punctatosulcatus. And since then, I’ve been on the hunt for more…

Heading out to numerous other museum collections I discovered more specimens, all collected in the same locality – Deal in Kent. In Ipswich Museum there are six, collected by C. Morley in 1896; there are two in the Natural History Museum, London, collected by G.C. Champion; and in the Museum of Zoology, Cambridge there are two collected by G.C. Hall in 1883.

Ipswich Museum
A view through the microscope of Melinopterus punctatosulcatus held in the collections of Ipswich Museum, collected by C. Morley in 1896

But the earliest and most recent finds are both in the National Museum of Scotland – one from May 1871, in the G.R. Waterhouse collection, and one from 1923, in the T. Hudson-Beare collection. So now we know of 42 specimens of this beetle with data and we know that the species occurred at Deal for about 50 years. But why are there no records after this time?

The Deal sandhills in Kent were famous for their insects, but even as long ago as 1900 entomologists* were discussing the negative impact of “summer camping-out stations and the modern craze for the ‘Royal and Ancient Game of Golf'” on beetles and butterflies in the area.

Today, most of the sandhills are gone and there are no grazing animals other than a few rabbits. Most of the surrounding land is either developed as a golf course or under agricultural management. So, is the possible local extinction of this dung beetle due to habitat loss and a lack of dung?

Deal
Deal, Kent: the original locality for Melinopterus punctatosulcatus, with remnants of the sandhills in the distance

To try and answer this question, naturally I went looking for poop in Deal. In a field in Sandwich Bay I could hear sheep bleating in the distance, although poo was scarce. Eventually I found a few old plops and inside were ten Calamosternus granarius, a small dung beetle. This was good, but my main target was Melinopterus punctatosulcatus.

Melinopterus punctatosulcatus edit
A specimen from the Museum of Melinopterus punctatosulcatus, previously listed as ‘Regionally Extinct’ in Britain, but now rediscovered in Deal, Kent

I probed the poop further. To my delight, crowded in the remaining squishy bit were four other species. On close inspection, one of these was hairy, so a male, and much darker than its close relatives. It fitted perfectly with my expectations for Melinopterus punctatosulcatus after seeing so many examples in museum collections. Success! This beetle, misidentified in museum collections for so long, and not seen since the 1920s in Deal, is indeed hanging on in Kent.

Disappointingly, after a further few days of searching, only a handful more specimens were seen. This suggests that either the species exists at low population levels, or that it was it was not the peak emergence period when I was there. Nonetheless, a species not recorded anywhere in the UK for over 70 years is actually still here.

Now hopefully we can encourage local land owners to help conserve this all-important dung fauna and flora.

* Walker, J.J. 1900. The Coleoptera and Hemiptera of the Deal Sandhill. Entomologist Monthly Magazine 36: 94-101.

Going, going… not gone?

by Darren Mann, head of Life Collections

Extinct or not extinct; that is a question raised by a report into the status of the beetles of Great Britain, published last year by Natural England. It may sound easy to determine whether a species is extinct or not, but tiny insects can be very hard to spot, despite the best efforts of many people.

The results of the report were alarming: using the International Union for Conservation of Nature criteria, just over half of our dung beetles are in decline, five have gone regionally extinct, and a further four were classified as Critically Endangered (Possibly Extinct) in Great Britain.

Prompted by this assessment, targeted surveys were made at known historic sites for some of our rarest and possibly extinct species. Over the past two years we have already made some exceptional discoveries, including new sites and new county records for several rare dung beetles.

 

My favourite finds from recent field exploits are the discovery of two new populations in Gloucestershire for the Critically Endangered Aphodius quadrimaculatus, and the rediscovery of Heptaulacus testudinarius in the New Forest, Hampshire after 35 years with no records. But sadly we have failed to find four of our target species at their last known sites.

Finally, after ten years of repeated site visits, we did finally find one of our rarest species, the Ainsdale dung beetle Amoecius brevis. This small beetle, just 3.5-4.5 mm long, was first found in Britain in 1859. It’s restricted to the Ainsdale and Birkdale sand dunes of Lancashire, where there were several records from the early 20th century, one record in 1962, and four records from the 1990s.

A specimen of Amoecius brevis from the Museum, collected in 1903

The last known record was of a single specimen caught in 1996. The lack of recordings for the past 20 years, despite a large number of surveys, led us to proclaim it Critically Endangered and ‘Possibly Extinct’ in the Natural England report.

Unlike many of our other dung beetles, which prefer fresh dung, Amoecius brevis breeds in older dung of large herbivores, such as cattle and horses, and rather unusually, in the UK it is also found breeding in rabbit latrines.

So it was in pursuit of rabbit latrines that we spent five days walking up and down sand dunes, covering an area of about 5km2. We then used a fine mesh sieve and tray to search through the dung and sand beneath. When our first beetle appeared it took a few minutes for the euphoria to fade, and then to our delight a further three were found in the next handful of sand and rabbit dung, along with a few more a little way down the coast.

In one sense, proclaiming a small, inconspicuous and evidently hard to find beetle as ‘Possibly Extinct’ is premature, but without that designation who would bother to go and look? Would wildlife conservationists give it any attention?

Since the Natural England Status Review was published, surveys have been commissioned for four rare dung beetles; in the case of the Ainsdale dung beetle at least, this has proven very successful.

I hope that the rediscovery of this very rare beetle will highlight the importance of invertebrate conservation as a whole. In the meantime, our data will feed in to conservation management plans for the Ainsdale site, safegaurding this little beetle’s future.

 

 

Delightful dung beetles

The latest display in our changing Presenting… case showcases a wonderful array of dung beetles. Darren Mann, head of our Life Collections, tells us why they are so important.

Worshipped during ancient Egyptian times, dung beetles have a long history of human appreciation. Jean-Henri Fabre (1823-1915), one of the first to popularise insects in his writings, began his Souvenirs entomologiques series with the Sacred Scarab, and even Charles Darwin appreciated the weaponry adorning many dung beetles.

Dung beetles can be divided into three main groups based on their nesting behaviour. The rollers, often seen on television wildlife documentaries, make a ball out of dung and roll it some distance before burying it. The tunnellers dig directly below the dung pile and bury as much as needed for nest construction. Finally, the dwellers nest within the dung pile.

The South American Phanaeinae is one of most colourful groups of beetles. They are often referred to as Rainbow Scarabs due to their bright metallic bodies. We don’t fully understand why these beetles are quite so colourful.

Dung beetles are one of the more popular groups of insects used in ecological and evolutionary research today. They can help us to understand questions about how biodiversity loss impacts on ecosystems, or act as model organisms in the field of evolutionary development.

Unlike the much-publicised importance of bees and their pollination services, dung beetles are relatively unknown, despite their huge ecological and economic value. Their feeding and nesting behaviours provide many useful ecosystem services such as dung removal, pest fly control, parasite suppression, nutrient cycling, plant growth enhancement, improvement of soil structure, secondary seed dispersal, and a possible reduction of greenhouse gas emissions.

Through these activities, one study calculated that dung beetles are worth around £367 million a year to the UK cattle industry alone.

The largest dung beetles belong to the genus Heliocopris, which can reach up to 69 mm (pictured is Heliocopris dominus). These large beetles specialise on elephant and rhino dung. From around 2 mm in length is the oriental genus Panelus. These small beetles probably feed on the ‘dung’ of other insects and fungi.

Ancient Egyptians believed that the dung beetle kept the Sun moving across the sky like a giant ball of dung, linking the insect to the god of the rising sun Khepri. Some historians believe that it was through observing dung beetle behaviour and biology that Egyptians developed ideas about life after death.

The two most widely depicted species in Egyptian art are Kheper aegyptiorum and Scarabaeus sacer. Nowadays, only Scarabaeus occurs in this region of Africa; Kheper is now a more southern species, possibly indicating climatic changes since Ancient Egyptian civilization.

Kheper aegyptiorum on display in the museum’s Presenting… case

The UK has about 60 species of dung beetle and most of these belong to the ‘lesser dung beetle’ subfamily Aphodiinae. The largest of our dung beetles are the Dor Beetles which can reach 28 mm. Our smallest, Plagionus arenarius, is a meagre 2.5 mm. Sadly, over 50 per cent of our dung beetles are in decline due to agricultural intensification, pesticides and habitat loss.

 

Why the world needs Dung Beetles

To celebrate National Insect Week 2016 we thought we would introduce you to the custodians of the Hope Entomology Collection here at the Museum. Our insect collection is made up of a whopping 6 million specimens, so our resident entomologists definitely have their work cut out. However, they have taken a little time out to tell us all about their specialisms and why their favourite insects are the best.

Darren Mann – Head of Life Collections

Darren out in the field collecting Dung Beetles

Dung beetles have been my passion since my late teens. I started with British species and then gradually broadened my interests to encompass the world fauna. But why dung beetles?

Well, they are beautiful insects, exhibiting an array of shapes and colours; they have been around since the dinosaurs, and have interesting biologies and behaviours, from nest-building and parental care, to stargazing. As a group, dung beetles are also very important in the ecosystem, removing dung and recycling nutrients.

Not only that, but dung removal and relocation offers additional ‘ecosystem services’ of fly control, livestock parasite suppression, plant growth enhancement, improved soil structure, reduction of greenhouse gas emissions, seed dispersal, and pollination. Inevitably, they are a source of food for other animals too.

Darren takes a closer look at a collected specimen

Dung beetles are found in all regions of the world, and consist of three main groups: the dor or earth-boring beetles (Family Geotrupidae) of around 600 species; the ‘lesser’ dung beetles (Family Scarabaeidae, subfamily Aphodiinae) of around 3,500 species; and the ‘true’ dung beetles (Family Scarabaeidae, Subfamily Scarabaeinae) of around 6,000 species.

With just over 10,000 species in total you’d think we have found all the dung beetles out there, but not so: it’s estimated that 40 per cent of species new to science are still to be discovered. In the UK we have just 60 species and over half of these are in decline due to agricultural intensification, pollution, use of veterinary drugs, and changes in livestock farming practises. The Dung Beetle Mapping UK Project (DUMP) aims to highlight the importance of this group and promote research and conservation in this area.

Despite their name, not all dung beetles eat dung, with some species preferring fallen fruit, fungi, or even dead animals. The South American roller (Deltochilum valgum) is an avid predator of millipedes and another South American species (Zonocopris gibbicollis) feeds on snail mucus!

So with their high diversity, fascinating ecology, and great economic benefit, perhaps the question really should be ‘why not study dung beetles?’.

Nature’s Waste Management Team

A Spotlight Specimens special for Oxford Festival of Nature

By Darren Mann, Head of Life Collections

One cow can produce over nine tonnes of dung per year. With a population of about 3.4 million cows in the UK alone, that’s a heck of a lot of dung deposited on our grasslands. Just imagine how much dung is produced every year if we include the output of horses, sheep, pigs, and all the wild animals out there.

Dor Beetle – Geotrupes mutator
Dor Beetle – Geotrupes mutator

All of this dung is broken down by a multitude of invertebrates, including flies, worms, and beetles, as well as bacteria, fungi, and weathering. One of the key groups involved in the removal and degradation process is the aptly named ‘dung beetles’.

In the UK there are 61 species of dung beetle, though sadly just over half of these are now in decline and some have already become regionally extinct. UK dung beetles vary in size from just 3 mm to over 25 mm and occur wherever dung is found, though some prefer sandy soils and others like to live in woodlands.

Larvae in dung pile
Dung beetle larvae (Aphodius fossor)

As adults, dung beetles feed on the liquid part of dung. The larvae of most of our species live inside the dung pile and are called the dwellers. These munch their way through the solid matter of the dung pile, gradually breaking it down over a few months. Other species such as Geotrupes mutator, pictured above, excavate a tunnel and bury the dung below ground. These tunnellers construct a brood chamber in which their young develop.

Aphodius fossor
Aphodius fossor

Through their actions, dung beetles perform a number of valuable ecosystem services. The most obvious is dung removal and degradation which leads to improved soil health by nutrient cycling and soil movement. By burying the dung they reduce the amount of available breeding habitat for pest flies and livestock parasites too.

All of these important services have been estimated to save the UK cattle industry £367 million per year. The value of dung beetles doesn’t end there as they also provide an important source of food for farmland mammals and birds. So next time you see a pile of dung in a field, just think of all the hard working beetles within…

Staff and associates of the Museum also run the Dung beetle UK Mapping Project – affectionately abbreviated to DUMP!

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