Going, going… not gone?

by Darren Mann, head of Life Collections

Extinct or not extinct; that is a question raised by a report into the status of the beetles of Great Britain, published last year by Natural England. It may sound easy to determine whether a species is extinct or not, but tiny insects can be very hard to spot, despite the best efforts of many people.

The results of the report were alarming: using the International Union for Conservation of Nature criteria, just over half of our dung beetles are in decline, five have gone regionally extinct, and a further four were classified as Critically Endangered (Possibly Extinct) in Great Britain.

Prompted by this assessment, targeted surveys were made at known historic sites for some of our rarest and possibly extinct species. Over the past two years we have already made some exceptional discoveries, including new sites and new county records for several rare dung beetles.

 

My favourite finds from recent field exploits are the discovery of two new populations in Gloucestershire for the Critically Endangered Aphodius quadrimaculatus, and the rediscovery of Heptaulacus testudinarius in the New Forest, Hampshire after 35 years with no records. But sadly we have failed to find four of our target species at their last known sites.

Finally, after ten years of repeated site visits, we did finally find one of our rarest species, the Ainsdale dung beetle Amoecius brevis. This small beetle, just 3.5-4.5 mm long, was first found in Britain in 1859. It’s restricted to the Ainsdale and Birkdale sand dunes of Lancashire, where there were several records from the early 20th century, one record in 1962, and four records from the 1990s.

The last known record was of a single specimen caught in 1996. The lack of recordings for the past 20 years, despite a large number of surveys, led us to proclaim it Critically Endangered and ‘Possibly Extinct’ in the Natural England report.

Unlike many of our other dung beetles, which prefer fresh dung, Amoecius brevis breeds in older dung of large herbivores, such as cattle and horses, and rather unusually, in the UK it is also found breeding in rabbit latrines.

So it was in pursuit of rabbit latrines that we spent five days walking up and down sand dunes, covering an area of about 5km². We then used a fine mesh sieve and tray to search through the dung and sand beneath. When our first beetle appeared it took a few minutes for the euphoria to fade, and then to our delight a further three were found in the next handful of sand and rabbit dung, along with a few more a little way down the coast.

In one sense, proclaiming a small, inconspicuous and evidently hard to find beetle as ‘Possibly Extinct’ is premature, but without that designation who would bother to go and look? Would wildlife conservationists give it any attention?

Since the Natural England Status Review was published, surveys have been commissioned for four rare dung beetles; in the case of the Ainsdale dung beetle at least, this has proven very successful.

I hope that the rediscovery of this very rare beetle will highlight the importance of invertebrate conservation as a whole. In the meantime, our data will feed in to conservation management plans for the Ainsdale site, safegaurding this little beetle’s future.