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Week 1-2/2010: Dung and carcasses

Madagascar, a tropical island that has been isolated from the rest of world for tens of millions of years, makes an ideal natural laboratory. Species have been discovered in Madagascar that do not exists anywhere else in the world, such as a hundred native primate species – and 250 native dung beetles that have specialised in eating dung produced by the primates.

“From the perspective of the dung beetles, the amount of dung available has been small and uniform in nature because the island has been completely devoid of ungulate populations, for instance,” says Heidi Viljanen, who defended her doctoral dissertation on the impact of natural history, human inhabitation and cattle rearing on the dung beetle populations in Madagascar at the Faculty of Biosciences on 27 November 2009.

Nature is resourceful

Although scarce, the dung resources have been sufficient to sustain ecologically similar beetle populations, as they have specialised through evolution to live at different altitudes in the forest terrain or to eat at different times of the day. The majority of the beetle species have also expanded their diet to include, for example, carcasses.

Only a week before Viljanen, another young researcher from the Viikki campus, Helena Wirta, defended her doctoral dissertation, which was also on Madagascar dung beetles. She studied the lineage of beetles through reconstructing evolutionary trees using several gene regions.

Both researchers are greatly concerned about the future of dung beetles. “Human beings are the dung beetles’ worst enemy. Some ninety per cent of Madagascar's forests have been destroyed,” says Wirta. “Felling a single stand of trees may cause the extinction of several species, because dung beetles – like many other species – inhabit very small areas,” says Viljanen.

Read more about dung beetle research in HUB.

Text: Pauliina Susi
Translation: AAC Global
Photo: Tuomas Kankaanpää

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