Getting Down and Dirty…
I have been writing blogs about birds of paradise , wines , all the good and pretty things in life ,… life isn’t always that rosy … so this time I decided to get dirty, really dirty and talk about an insect that gained my respect as I read more about it: the dung beetle!
Hence their name, it’s obvious that dung beetles have a bit of a weakness for poo.
Though that might be an understatement in their particular case…seeing how they eat poo and some of them not only eat poo, but live in it as well and deposit their eggs in small packs .The more artistic varieties of dung beetle sculpt chunks of poo into beautifully round balls which they roll away and bury it as a treat for the harsh times and even turn it into a dung beetle nursery.
Once worshipped by the Ancient Egyptians they were linked with Khepri – the Egyptian god of the rising sun – because the Egyptians saw the dung beetles rolling balls of poo across the ground as a symbol of the forces that moved the sun across the sky. Their status has now slipped to that of unsung and forgotten hero… Yet the dung-beetle is truly heroic. It is a well known fact that were it not for the dung-beetle the world would be knee-deep in animal droppings. By burying that waste dung beetles not only remove it from the surface, they improve and fertilise the soil and reduce the number of disease-carrying flies that would otherwise infest the dung. The fertile grasslands we all take for granted we have to thank them for it!
If the modern dung beetle deserves praise for their global sanitation efforts, then the extinct dung beetles of ancient South America deserve a statue. Some 30 million years ago, the continent was home to the South America Megafauna, including some truly giant extinct herbivores: armadillos the size of a small car, ground sloths 6 metres tall and elephant-sized hoofed-mammals unlike anything alive today. And of course, megafauna would have produced mega-dung.
Fossilised dung beetle poo balls have been found proof that our heroes have been around for over 30 million years.
Dung beetles are amongst the most studied subjects of the insect world….it seems there have been 32,000 serious studies into the life, love and universe of a small beetle that eats poo.
And they keep surprising science….
They come in a broad range of colours, sizes and varieties. Many of them roll the poo they find into balls which are used as a food source or a cosy place to lay their eggs. These are imaginatively referred to as “rollers” and they are small but mighty, they can roll up to 20 times their own weight. Other types include “tunnelers”, which bury poo wherever they find it, and “dwellers”, which live in poo giving a whole new meaning to the phrase “I’m in deep shit”. Also there is a group called the robbers, these one are kinda triad beetles who will rob the already dungbeetle balls from passing rollers…. If the original roller of the poo ball can’t make a speedy escape, he is likely to find himself surrounded by an enthusiastic band of robbers all very determined to relieve him of his hard-won ball of poo.
Dung beetles have an excellent sense of smell and use this for sniffing out poo. Once they have found themselves a suitably fragrant pile, the male dung beetle grabs a bit of poo and then sculpts this into a ball which he then runs frantically away in a straight line with it and buries it.
So, why the straight line? He needs to take the most direct escape route possible to guarantee that he doesn’t return to the thieves at the poo pile. If one of the other beetles steals his ball, the original beetle will have to start again from scratch, which is a big investment of energy for a small creature.
The dung beetle will, before rolling its poo ball away from the poo pile, take the time to do a little dance on top of it .
If you look at the image of a dung beetle rolling his poo ball you will see that they do this while practically performing a handstand as they roll it backwards with their hind legs while walking head down on their hind legs, logistically not the easiest…. it turns out that dung beetles have two pairs of eyes, one pointing up and one pointing down. So, even when they are effectively upside down, they can still see the sky .
Scientist knew that the dung beetles used the sun to orient themselves for their straight line dash. It was all very clear how dung beetles got around during the day, but some scientists got to ask themselves how it was that dung beetles still managed to run in a straight line at night when they obviously couldn’t see the sun and given that the moon has a much weaker pattern of polarised light. What they found was puzzling – most dung beetles could still roll a ball in a straight line, even on nights where there was no moon, provided it was an otherwise clear night. However on overcast nights, they were not so successful at establishing a straight line trajectory. They did some tests with little hats avoiding the beetles from looking upat the sky during their little orientation dance,they all got lost!
The study ended up demonstrating that dung beetles can navigate by the stars, and that a particular species of dung beetles (Scarabaeus satyrus) can also navigate by the Milky Way. This is the first proven use of the Milky Way for orientation in the animal kingdom! The dung beetles use the gradient of light to dark in the Milky Way to ensure that they are rolling their poo in a straight line away from the poo . Makes me feel small and disconnected again, I barely find my way in Central after 2 years ….google maps? Hmm
Once thing that you might find surprising but very relevant to know, is that dung beetles are very important for farming. Through their activities of burying and eating livestock poo, they help return nutrients to the soil and keep the pastures clear. they bring up quite some subsoil making their burrows, improving soil structure, drainage etc also by getting rid of the poo lying around in the grasslands the dung beetles also help protect livestock from pests like flies and biting midges which breed in poo, as well as ensuring that the ratio of grass to poo continues to be in favour of the grass.
Of course other animals like earthworms, ants and termites can also breakdown poo, but none of them really have quite the same passion for poo as the dung beetle.
Dung beetles play a really important role in our ecosystems and especially when it comes to healthy soil and fertilising it. The number of different species of dungbeetles is a good indicator of your ecosystem ,In Hong Kong on Lantau island in the Pui O wetlands there is still a herd of around 60 waterbuffalos and 21 species of dung beetles have been recorded, in Mui wo there is a small population of 5 remaining waterbuffalos and only 6 species of dung beetles are present .
Another surprising fact is that dung beetles are actually fuzzy eaters, I hear you think: go away ,they eat poo and love it so if you fine with poo you eat everything…
Wrong,very wrong !
This is something Australia found out the hard way….Australia used to be as we all know inhabited by the Aboriginal people and there were mammals on the continent ,mostly marsupials and their dung was always nicely cleaned up by native dung beetles who evolved alongside these special mammals for thousands of years.
A good 200 years ago settlers from all over the planet moved to Australia and started farming and keeping domesticated animals like cows, horses, sheep etc, so far so good till a good two years later the government got confronted with a huge problem…Australia got literally covered in dung, the native dung beetles weren’t interested at all in ‘the exotic poo’, a real crisis appeared and there was no other solution but to import dung beetles from the countries where the livestock originated from…they all started cleaning up the dung from the for them known animals and reproduced fast.
The same program is now being set up since 2013 in New Zealand.
As it is a great natural way of airing and fertilising the soil dung beetles are getting really popular in permaculture farming as well and well set up programs show really nice results, back to nature seems to be the way to go!
Seems the earthworms will need to share their glorious status with the dung beetles: It’s a dirty job but someone got to do it! All respect !
Abstract from article “Dung Beetles Use the Milky Way for Orientation”, 2013 by Marie Dacke, Emily Baird, Marcus Byrne, Clarke H Scholtz and Eric Warrant.
Dung Beetles in New Zealand (Website)
National Geographic Weird and Wild, “Dung Beetles Navigate Via the Milky Way, First Known in Animal Kingdom” – January 24, 2013 by Christine Dell’Amore
National Geographic Weird and Wild, “Why do dung beetles Dance”? 18 January 2012 by Christine Dell’Amore
Wits University (2013, January 24), “Dung Beetles Follow the Milky Way”