At this time of year, there is a particular increase in attention when scanning the road ahead from our game drive vehicles. We are bound to either pass a fresh pile of dung bursting with life from dozens of dung beetles or to come across a perfectly circular ball of dung rolling across the road. And when this happens, it is always entertaining to pause for a few moments to witness snippets into the life of such small creatures.
Dung beetles fight over fresh zebra dung. Wonderfully entertaining insects to watch, I have spent many game drives and bush walks with guests totally enraptured by their antics, whether fighting, rolling balls or just scuttling along. In fact, the presence of dung beetles is probably one of my top 3 favourite things about summer.
Dung beetles vary in size and colour depending on the species. We understand there to be around 800 species of dung beetles in South Africa, 2000 species in Africa, and approximately 6000 in the world. However, the majority of these species we never really see since they bury themselves in the dung and shuffle between the dung and the soil surface, nesting underground.
Here at Londolozi there is an abundance of a particular sub-group known as telecoprids; these are the dung beetles that roll impressive balls of dung. The male dung beetles set out every day in search of fresh dung to build either a nuptial ball (rolled for a female for them to consume and mate in) or a brood ball (rolled as a larder for the dung beetles larvae). A previous blog describes the various types of dung beetles and how they differ in more detail.
In this blog, I want to share some of the research and literature published by Marcus Byrne, a professor at Wits University in Johannesburg, who also happened to win the 2013 Nobel Prize for Biology/Astronomy for his study of these incredible small creatures:
“A dung beetle has a brain the size of a grain of rice, and yet shows a tremendous amount of intelligence when it comes to rolling its food source (animal excrement) home. How? It all comes down to a dance.” – Marcus Byrne.
How do dung beetles orientate themselves?
Dung beetles roll their dung balls head down in a backwards direction, basically doing a handstand and pushing their ball with their back feet. So how do they know which direction to move?
If you ever watch a dung beetle rolling a ball, you will notice every few seconds they pause, climb on top of the ball, and dance in a circle atop the ball before climbing back down to continue rolling in a straight line. Marcus Byrne and his research team have studied the intricacies of the behaviour of these beetles. It has been proven that they depend on celestial cues for their sense of direction (sun, moon, stars as well as the milky way). Every time they are atop the ball they quickly reevaluate their surroundings to orientate themselves before continuing on their journey of rolling the ball towards its intended destination. This action has become known as the “dance of the dung beetle”.
How do the dung balls help with thermoregulation?
Another behaviour we get to observe every now and then is that when the beetles climb on top of the ball, they wipe their face. And on a hot summer’s day when the ground is hot, they dance more often. When they do this particular dance they wipe the bottom of their face. It has been further proven that not only does the dance of the beetle help with their sense of direction, but the dancing on top of the dung also help the beetles regulate their temperature.
When the ground is very hot, dancing on top of the dung ball helps cool the beetle down, particularly its head and front feet. To try to personify this behaviour: just imagine walking along beach sand on an extremely hot summer’s day – the hotter the sand, the more frequently you’d be trying to jump between beach towels to avoid burning your feet. In a similar behaviour, the hotter the environment, the more frequently the beetle dances on top of the cooler ball.
How ecologically important are dung beetles?
Like vultures and hyenas, dung beetles are essentially ‘scavengers’; coprophagous insects that feed on the excrement of animals. They play a critical role in recycling the organic matter in nature as well as nutrients back into the earth’s surface. Once buried in the ground it decomposes, aerating and fertilizing the soil. The removal of dung also minimizes the number of flies (by lowering the number of breeding sites for their eggs), so these beetles are extremely useful in maintaining a healthy environment.
It is believed that dung beetles can bury more than one metric ton of dung per hectare per year, which is an incredible feat given how small the dung beetles are.
So if you happen to be on your next safari during our summer period, keep an eye out for some of the smaller creatures bustling about right next to the road!
Kate Arthur
Source link
