When it comes to exemplifying the motto “waste not, want not”, dung beetles rule. There are about 6,000 such species that relish fiddling with faeces: rolling it into balls, burying it, laying eggs in it, and feasting on it.

These glossy insects contribute to the smooth running of the planet by, among other things, aerating soil and disposing of dung heaps containing parasites that would otherwise infect livestock. Dung beetles, though, are under threat from habitat loss, pesticides, invasive species and, in tropical areas, climate change. A scientific review published this week also identifies moths and butterflies as especially vulnerable.

At current rates of decline, according to the journal Biological Conservation, about 40 per cent of insect species face extinction within the next few decades. There are implications beyond unprocessed poop: insects are an essential link in the food chain, and their loss would starve the birds and mammals that feed on them.