I notice a team of researchers have announced in the journal Science that a population of Greenland sharks contains individuals as old as around 400 years. A few people have raised questions (not explored in the paper) about the potential for old sources of the carbon-14 used in the process to have hung around a long time in the stable Arctic environment, making the sharks appear older than they are. Nonetheless, the ages quoted are pretty incredible if true and even if it’s an overestimate these are likely to be the oldest known vertebrates alive.
The good news for would-be explorers of the natural world marooned in rainy-ol’ Britain is that there are plenty of similar mysteries on our doorstep. We simply need to think a bit smaller! Try about 3mm long, for example. That’s the size of the beetle in the right of the picture below, taken in the University of Reading’s ‘Wilderness’ on the 2nd of August. A few more of its kind, Anaspis costai, were hanging out on the same small cluster of fading hogweed flowers.
I walk past the flowers in question twice a day, once in the morning between 8 and 8:30 and again between 5 and 6:30 in the evening. The following day, a few more A. costai had joined the party – about 8 – and a similar number remained present through the rest of the week. I wondered if they’d remain over the weekend. Sure enough, there they were on Monday morning. And Tuesday, Wednesday and Thursday! I say they: how do I know they were the same beetles?! For so many species of insect we don’t even have this kind of basic information. How long do they live, how far will they travel in a day, how far do they disperse over the course of a lifetime?
What I needed to have done was marked as many of them as I could on day 1, perhaps with a tiny blob of enamel paint on the tip of a wing case. That’s what my PhD supervisor Graham Holloway did back in 1987, just around the corner on the same site, with a population of Eristalis pertinax hoverflies. These beetles would make trickier subjects – they’re small and very susceptible to disturbance – so I’d struggle to match the impressive total of 1223 insects marked in the hoverfly study. It would give me some satisfaction just to mark a few, though, and get anywhere towards knowing whether my beetle friends are the same individuals day after day, feeding on the same flower head, or if they represent turnover of newly emerged adults dropping out of the scraggly oak just above. There really are mysteries wherever we look, as insignificant as they may seem in the general scheme of things.