Surveys for the Red-barbed Ant in Scilly – new adventures in entomology!

Saturday 12th August 2023

…guest blog by Holly Whitehouse.

Never in my life had I taken the time to ponder the great delight that washes over a person who had just found an approximately 4mm by 4mm hole in a sandy bank of soil. And yet, that delight was the principal feeling of my fieldwork trip to St Martins in the Isles of Scilly.

St Martin's - Isles of Scilly - waved heath © BareFoot Photographer
St Martin’s – Isles of Scilly – waved heath © BareFoot Photographer

The first trip up to the site around the Daymark (a large red and white painted cylinder, topped with a cone to aid navigation at sea – for those who are not familiar with the term) brought with it little success; we had spent at least 45 minutes finding ants – but not the ones we were looking for – the Red-barbed Ant (Formica rufibarbis). However this did give us time to “get our eye in” (according to my Dad), and also gave me the time to admire the majesty that was the waved heath. It was (in many senses) much like the ocean- yet dark and green and dotted with hundreds of tiny purple patches of heather. In fact, it would have been a most pleasant experience, and perhaps even an opportunity to locate some of the nests of the Red-barbed Ant, if it were not for the sudden rain that began to pitter patter on the dusty inclines that these ants so commonly inhabited. But yet we pressed on despite the falling temperature and thick mizzle, and eventually found one Red-barbed Ant out foraging – so one morning, one ant, no nests! After that, we decided it was becoming much too cold and wet, and decided to make a dash to the nearest cafe to warm up over some tea and cake – for even the ants hated the bad weather, and would not have been out in the conditions.

Day two began with a light touch of rain – a terrible dampening for both our tent and our spirits, and one that happened again when we met with my Dad’s friend, Nikki, who had brought her dog, Eysa – at which time we hid in the St Martins ferry waiting room for shelter. After the rain had passed, we began our survey walking up the coast path on the other side of the island as we did the day before when we walked up to the Daymark, and soon enough, on a warm dusty slope leading down from the hedge to the footpath, Nikki found one of our ants. Actually, upon closer inspection, it seemed we had found many of our ants! All in one patch – and it certainly didn’t take long after this discovery to find the entrance to their nest. You see, Red-barbed Ants leave very little indication as to where they put their colonies; no raised earth, no pile of thatch, no hundreds of burrowing holes, and often no little piles of earth that would indicate digging (at least by my experience). And thus the only way to successfully locate one of these illusive nests is to watch the ants and find the hole they are going in and out of.

Holly & Andrew with a Red-barbed Ants nest © BareFoot Photographer
Holly & Andrew with a Red-barbed Ants nest © BareFoot Photographer

After that, I found a nest, tucked in beside the path, under a taller patch of grass. My Dad took it upon himself to poke the entrance of the nest with a pencil, causing many of its inhabitants to come pouring out of the tiny cavern to see what was the matter.

After this lively encounter we took to the beach nearby and found an unexpected abundance of nests – in the previous surveys only one nest was found at this spot, but we found five! Often we would find a nest by lifting up a rock and it being underneath – and it was at these times that we got to see the ants exhibiting very interesting behaviour. Now, I’m no expert on ants, nor was I particularly interested in them specifically before this trip – for I find spiders, beetles and slugs much more interesting – but in seeing them work together for a common goal was incredible, and now I feel I have a much greater appreciation for these charming, tiny soldiers. Red-barbed Ants are heat-loving insects, so they will dig their colonies near rocks or near the surface in order to experience the most heat, and (critically) make sure their larvae are getting warmth to help them develop. So, whenever we found a colony under a rock, the ants would have placed their young directly beneath the rock to keep them warmer, and so when we lifted up that rock, all of the worker ants would scramble to take their young deeper into their maze of tunnels to protect them from the elements, and who or whatever had exposed their colony. I took the time to marvel at their organisation – how could such a small creature be so intelligent as to know to keep their young in the hottest part of the nest, or be so loyal as to prioritise their larvae over their own lives? Ants really are one of the most interesting invertebrates – turns out.

Red-barbed Ants (Formica rufibarbis) St Martin's © BareFoot Photographer
Red-barbed Ants (Formica rufibarbis) St Martin’s © BareFoot Photographer

After a spot of lunch and a patch of rain, we had (along with locating many nests along the way) reached the Daymark and the waved heath that sprawled out around it. There, we found our last few nests via a great many methods; following ants, probing the ground (pencil again!), and through the help of Eysa the dog (who dug up an entrance upon accident). In these last hours it was nice to take a moment to admire the work we had done and the positive impact it would hopefully have on learning more about this species and aiding it in the future. And as we waved goodbye to St Martin’s on the boat trip home, I could smile to myself, safe in the knowledge that, even though it would have been nicer to visit some other sites suspected to house colonies (the islands of Nornour and Teän) we had successfully found 25 colonies, all of which with the potential to produce prince and princess ants that could one day fly off to make more, new colonies of their own, and that, my readers, was wondrous enough in itself!

Holly is 16 and from Plymouth in Devon.  Having just finished their GCSE exams, they jumped at the opportunity to spend time helping the conservation of one of the UK’s rarest insects!

Holly was helping with surveys for the Red-barbed Ant on St. Martin’s in the Isles of Scilly.  This is part of a collaboration between Buglife and the Isles of Scilly Wildlife Trust.

Main image credit: Red-barbed Ant (Formica rufibarbis) © Ian Beavis