The Dung-beetle: insect study highlights brunt of climate change

WINDHOEK, 30 JULY – A Namibian scientist – with the help of funding from the Nedbank Go Green Fund – is investigating the impact of climate change in Namibia through a study of dung beetles that have evolved to become highly sensitive, and underrated, ecosystem watchdogs.

Project leader Heather UJ Nependa, who is pursuing a masters in entomology at the University of Stellenbosch, describes dung beetles as “robust detector species” that could help Namibians better understand the challenges faced by the country’s already fragile ecosystems and landscapes as a result of climate change.

She said while many people are put-off by dung beetles,they should be appreciated more for the instrumental role they play in healthy landscapes and their ability to help scientists answer important questions.
“Though their lifestyles are strange and maybe a little nauseating, the work they do is crucial to the function of ecosystems.”

She added that the Nedbank Go Green Funding was a lifeline to a project few wanted to touch.
“It is difficult to secure funding for a project like this that does not focus on a charismatic and appealing species, however thanks to the Nedbank Go Green Fund and their commitment to sustainable development and an overall holistic view on conservation, I received funding.”
With the guidance of her lecturers in the Entomology Department, she chose to focus her project on dung beetles because of their close links to many mammal species and savanna landscapes.
“They are an environmentally sensitive species and are highly affected by plant density and diversity, and also importantly, to dung resources.”

Consequently this means that they give an indication of habitat quality and how environmental change is impacting landscapes.
Furthermore, changes to their diversity and abundance could affect overall ecosystem health in a landscape “which is a cause for concern”, Nependa said.
She added that apart from measuring the impact of climate change, studying dung beetles could also be a good way to measure whether current conservation efforts are effective.

THE JOB NO ONE ELSE WANTS

“Each day, the animal kingdom produces roughly enough dung to match the volume of water pouring over Victoria Falls, meaning that without the work of dung beetles the planet would be literally covered in poop. Besides clearing this dung, the actions of these animals have considerable ecological importance,” Nependa pointed out.

A tunneler dung beetle, the Copris species. PHOTO: HEATHER NEPENDA

A primary function of the dung beetle is to disperse seeds, which ensures the growth of important forage for other animals.
The seed dispersal role of dung beetles is so important, Nependa says, that one plant (Ceratocaryum argenteum) evolved smelly seeds to trick dung beetles into burying them.
Dung also contains excellent nutrients, which when buried by dung beetles, acts as an important soil fertiliser for plant growth.
Nependa referred to a recent study in the United Kingdom that estimated the value for the work dung beetles do to clear British pastures and fertilising soil as amounting to 370 million British pounds per year.

In Africa, their astounding diversity is underlined by the amount of species, 5 700, found on the continent.
“What is even more remarkable and strange, is their preoccupation with faecal excrements,” Nependa added.
A single elephant dung can attract up to 4 000 dung beetles in only 15 minutes.
Dung beetles operate in three types, namely “rollers, tunnelers and dwellers”.
Rollers shape dung into balls and roll them away from the dung pile, which they then bury and later use to lay eggs in.

Tunnelers “dive right into the dung pile”, usually in male-female teams and dig a tunnel beneath the pile. The female beetle then stays in the tunnel, processing the dung that is delivered by the male who scurries to and fro.
Dwellers on the other hand “simply live in the dung pile”.
Female dwellers lay their eggs there and when their young hatch they “blissfully munch away on the food that surrounds them.”

A tunneler dung beetle, the Copris species. PHOTO: HEATHER NEPENDA

A NAMIBIAN FIRST
Nependa’s project, titled ‘Dung beetles as indicators of ecological disturbance in Namibia across a resource and land-use gradient’ is aimed at chiefly highlighting the importance of “how delicate our ecosystems are and how the disruption of one thing can permeate through entire ecosystems to all Namibians.”
In order to obtain those answers, the project is exploring and evaluating the effects of land-use changes, which require comparing a natural landscape to modified areas such as farms, by analysing Dung beetle diversity and abundances.

A higher species diversity indicates a more stable and intact landscape compared to low species diversity.
Within Nedbank there is a broad consensus on the support of environmental initiatives, such as the Go Green Fund. “The relationship between ecology and economy is not as competitive as many assume and embracing eco-innovation in how we work has become imperative. Within Nedbank our entire mission is to promote sustainability, which is why projects such as the dung beetles in Namibia are important.” Said Gernot de Klerk: Head Marketing and Communications.

“The main aim of the study is therefore to determine whether there truly are huge, deleterious differences between these two landscapes or if they are being equally affected by anthropogenic threats.”
To date, only few studies have looked at dung beetles and their overall status, diversity and ecology in Namibia and as a result Nependa’s work has already begun to improve on the scarce knowledge of the insects in Namibia.

Photo of green beetle – A green dung beetle with a rolled dung ball – Garreta species. PHOTO: HEATHER NEPENDA

Specimens collected to date have unveiled a few species that were previously not thought to be found in Namibia, which has lent the project added taxonomic important for dung beetle ecology in Southern Africa.
She added that the results of her Nedbank Go Green funded project so far have shown a slight loss of species on the farm sites that were sampled, compared to the reserves sampled. – NDN Staffer