Why Dung Beetles Are the Unsung Heroes of Our Environment
Geetha Iyer
In one example, for livestock farmers, dung beetles increase foraging palatability, check the breeding of pests and help recycle nitrogen through the soil.
Ornithologists kept raising the alarm, yet very little attention was paid till the number of vultures became alarmingly low. The struggle to protect them is turning out to be a stupendous task. Now, the bugle for another species has been sounded – this time by the entomologists. For dung beetles. Like the vultures, the dung beetles are scavengers, coprophagous insects that feed on the faeces of animals (including humans). Their diversity and numbers have been on the decline. Is anyone listening?
In a 2005 paper, the scientist I.C. Mittal raised this issue: “Monitoring the diversity and conservation status of dung beetles is important because they play a critical role in recycling the organic matter in nature, but also because they are on decline now.”
In 2011, Simi Venugopal from Loyola College, Chennai, studied the diversity and community structure of the dung beetles in the semi-urban agricultural lands of the Malabar coast and found a decrease in diversity and a change in their community status. A year later, Sabu K. Thomas, an associate professor from St Joseph’s College, Calicut, and his students recorded species loss in five genera of dung beetles in the moist slopes of the Western Ghats in South India. The team concluded that “ these are vulnerable genera that may disappear due to habitat modifications occurring intensely in the region.”
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Studies in other parts of the globe have also been unraveling a similar story playing out: the dung beetle’s diversity is falling.
Why should we care?
Because of the effects they have on their ecosystem – and ours.
Based on their reproductive habits, the dung beetles are categorised as rollers, tunnellers and dwellers. The rollers make balls from dung pats and then roll them farther away, to a simple underground burrow. Here, the dung balls are buried for other beetles to feed and breed in. The tunnellers build elaborate underground chambers close to or beneath the dung pats using the fibrous parts from the dung. The dwellers live within the dung and breed.
This stratified living helps reduce competition for the precious resource that is the dung, at least to some extent. However, there are as many opportunists in this world of beetles as there are among humans. Some dung beetles are kleptoparasites, stealing dung balls at the first chance. The French naturalist Jean Henri Fabre has documented such behaviour extensively. In one case, according to him, the male that had helped a female roll the dung and had been expected to guard it tried stealing and running away with it. The female was busy digging a burrow to bury it. Watching the dung beetle’s antics can be quite entertaining.