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.

 

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