This week, the IUCN published the updated Red List, an ever-increasing database of species’ extinction risk. The latest update included assessments for many freshwater molluscs and cuttlefish, that were created, in collaboration with international species experts, by the ZSL’s Indicators and Assessments Unit.

Most people have probably heard about the plight of the giant panda or the tiger (both listed as Endangered on the Red List), but what about the status of species such as Sisyphus caffer or Onthophagus rhinoceros? Why do we care so much about how invertebrates, such as these two species of dung beetle, are faring?

Copyright Patrick Coin

Important as they are for their own intrinsic as well as cultural value (scarab beetles, members of the dung beetle family Scarabaeidae, were sacred to the ancient Egyptians), dung beetles also have crucial economic importance. It has been estimated that in the USA alone, dung beetles prevent the loss of $380 million annually by processing waste from domestic animals, and preventing pest species from breeding on this waste. Without dung beetles, many areas of the world would be piling up waste much faster that it would decompose.

At the Indicators and Assessment Unit, we have been throwing ourselves into this world. With just over 6,000 described species of dung beetle, assessing the threat level of them all would itself become Sisyphean. Instead, using a sampled approach, we are assessing 1,500 randomly selected species from around the world, as a short cut to create a general global view of the health of dung beetles as a group. This data also aids in our understanding of the threats to invertebrates in general, a group that is incredibly diverse but that we are still lacking in knowledge.

While undertaking this project, we have been in contact with experts from all over the globe. So far, we have learnt that not only are they passionate about their scarabs, but that there is an incredible diversity in dung beetle ecology and the threats affecting them. Furthermore, factors that are putting some species at risk are doing positive things for other species, such as a change in the local fauna species composition, changing the types of dung around that these beetles so dearly love. Mimicking trends with other taxonomic groups, species that are able to adapt to many sources of their favourite raw material (those without any particular dung preference) are often doing well for themselves. With the overall increase in cattle pasture land we are seeing world-wide, these generalist species are doing very nicely with all that extra cow dung. Other species, on the other hand, are of a more specialist, or dung discerning, nature and their future often relies on the continuing existence of certain megafauna in their local region, such as elephants and rhinos.

Clearly, to keep the dung balls rolling into the future, we need to understand the overall picture of how dung beetles are faring. So far, we have completed nearly one-fifth of the 1,500 species we aim to assess by the end of the year. While not quite the impossible task of ancient mythology, our friends of genus Sisyphus and co. will no doubt keep us busy into the future.

Dr Monika Böhm & Daniel Hall

Indicators and Assessments Unit, Zoological Society of London (ZSL)