Going batty in Southern Africa

The Cohen’s horseshoe species is only found in Mpumalanga in the Sudwala area near Nelspruit.
(Image: Patty Ruback)

Dr Samantha Stoffberg was responsible for the conclusive DNA studies that identified four new horseshoe bat species.

bats-text3 The Mozambican horseshoe bat is a medium-sized species in the complex. It is widespread in Mozambique and northwest Zimbabwe.
(Images: Stellenbosch University)

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A group of South African zoologists and bat experts are part of an international team that has discovered four new species of horseshoe bats in East and Southern Africa.

The discovery puts a spotlight on improving efforts to conserve the continent’s rich and expanding biodiversity, protecting new bat species in South Africa and recognising the important role of these flying mammals in the ecosystem.

Previously scientists thought that there was only one type of large horseshoe bat, Hildebrandt’s horseshoe bat (Rhinolophus hildebrandtii), widespread throughout East Africa, Zimbabwe and South Africa’s Mpumalanga province.

However, after years of research, piecing together clues such as DNA data and the frequency of sonar calls, scientists have found that there are in fact four other species.

They are: Cohen’s horseshoe bat (Rhinolophus cohenae), Smithers’ horseshoe bat (Rhinolophus smithersi), the Mozambican horseshoe bat (Rhinolophus mossambicus) and the Mount Mabu horseshoe bat (Rhinolophus mabuensis).

The study was led by bat experts and evolutionary geneticists Prof Peter Taylor of the University of Venda, Dr Samantha Stoffberg of Stellenbosch University (SU), Prof Ara Monadjem of the University of Swaziland, Dr Corrie Schoeman of the University of KwaZulu-Natal, Dr Julian Bayliss of the Conservation Science Group at the University of Cambridge in the UK and the Mulanje Mountain Conservation Trust in Malawi, SU’s Dr Woody Cotterill and the Africa Earth Observatory Network.

Conclusive DNA evidence

Stoffberg, who is a postdoctoral researcher in the evolutionary genomics research group of the Department of Botany and Zoology at SU, was responsible for the conclusive DNA studies.

“Describing new mammals is not that common, and certainly not four at once,” Stoffberg says. “And there are more on the way.”

She explains that the newly-described flying mammals are good examples of cryptic species, which means that they are difficult to tell apart based on their external appearance.

This is one of the biggest challenges in the study of bats, says Stoffberg. “Because they all fly and echolocate, they look very similar. DNA comparisons have made it possible for us to clearly distinguish between these species.”

The scientists also used other characteristics such as skull shape, genitalia and DNA sequencing to identify and classify the new species.

Distinct sonar calls

Horseshoe bats can all be identified by their horseshoe-shaped noseleaves, which amplify and direct their very distinct echolocation calls.

Echolocation, a biological sonar system, is a fascinating navigation tool used by mammals such as bats and certain birds that enables them to fly in the dark.

Echolocating animals release a call and then listen for the echoes to return from objects near them. The echo of the sound waves helps these animals to determine the shape of surrounding objects.

These specific calls were the first clues that the scientists scrutinised. “We found these differ not only among bats from various parts of Africa, but critically of bats found in the same localities,” said Cotterill.

Renewed efforts to study and protect bats

Stoffberg developed an interest in bats when she was a third-year student at the University of Cape Town. “We were exposed to bats as one of the study animals and I was hooked,” she says.

“There is so much about bats that we don’t know, especially in terms of answering evolutionary questions.”

According to Stoffberg accurate identification of bats is important to ensure that the best conservation efforts are put in place to protect these animals.

“The discovery of the new species is important in terms of conserving South Africa’s biodiversity,” she says, adding that knowledge of a bat’s geographical distribution, particularly if it is limited such as that of the Cohen species, is important for its survival.

“To conserve something you need to know what you have,” she explains.

The Cohen species is only found in Mpumalanga in the Sudwala area near Nelspruit.

Prof Peter Taylor of the University of Venda, lead author of the study, is not aware of any other bat species being endemic to Mpumalanga, which highlights the conservation importance of the Cohen’s horseshoe bat.

Cotterill explains that the Smithers’ horseshoe bat only seems to be found in the northwestern regions of the Zambezi escarpment in Zimbabwe, remote areas of the Kruger National Park in the Pafuri area, and the Soutpansberg Mountains in Limpopo.

These bats have the highest echolocation frequency of all the members of this species-complex.

Pest control and pollination

Bats also have an important role in the ecosystem. “They eat a lot of potentially harmful agricultural pests and keep insect populations in check,” Stoffberg says.

They are also very effective pollinators because unlike birds, they travel further. Fruit bats, for example, are responsible for pollination of baobab flowers.

Stoffberg says that the study of bats has been neglected, but with advancements in technology it is becoming easier to study these fascinating animals.

Slideshow image courtesy of welchlinks.com