Hello Bloggers!
I am sure that everyone reading this blog will agree with me when I say that EJ and Odin’s nest is a very impressive work of art. It’s a whopping 5.5ft wide and 6ft tall. That being said, I am sure that they wouldn’t mind me drawing your attention to a different type of nest this week. These nests have been drawing my attention in the past month or so, as the warm weather has been bringing them to life all around Abernethy.
In case you didn’t guess from the title, I am going to write about wood ants. I often over look the smaller residents of the Caledonian Forest as it is so much easier to “ooooh” and “aaaah” at larger fluffier animals such as wildcats and ospreys. When I do occasionally take a closer look at the micro world, I always come away amazed and intrigued. I have been noticing wood ant nests for years but recently realised that I don’t know much about them. If you are in the same boat as me then keep reading and we can learn together.
Video of wood ants nest
Their nests look like a dome shaped pile of pine needles up to 1m high and 2m wide. The ants are extremely clever and are able to control the environment within the nest to make sure it is favourable to raising eggs and pupae. Nests are often built on decaying tree stumps which provide heat. The nests are asymmetrically shaped, with a flatter southern side to allow maximum absorption of heat from the sun. Entrance passages are opened and closed by workers regularly to control heat and humidity within the nest. They arrange the needles like roof tiles to encourage fast run off of water. They also sunbathe outside the nest and then release their body heat in the chambers where the eggs and larvae are kept.
Very tall wood ants nest
There are four different species of wood ant found in Scotland: Formica aquilonia, Formica lugubris, Formica exsecta, Formica sanguinea. F. exsecta and F. sanguinea are the rarest of the four species as they have gone extinct in most pine woodlands in Scotland. F. sanguine is only known to be present in three forests in the highlands: Glen Affric, Abernethy and Migdale.
Worker ants on the nest
Close up wood ant by Jackie Cooper
Wood ants are a very important puzzle piece in a forest ecosystem because they control herbivorous insect populations (e.g. sawfly and pine looper moth caterpillars which eat pine needles) and have unique interactions with many other organism which benefit from the worker ants hard work. I feel that humans could learn a lot from wood ants. They welcome many foreign guests into their nests which are treated as one of their own, being given food and protection... something maybe we could take inspiration from. For example F. sanguine tolerate the beetles, Lomechusa strumosa, in their nests. Outside of their nests they have a symbiotic relationship with many aphid species. The ants feed on the honeydew that the aphids secrete and the aphids receive protection from predators and other sap sucking competitors. Capercaillie also benefit from the presence of ants nests as they like to use them for dust baths... definitely not a relationship that the ants benefit from!
Wood ant colonies in Scotland contain around 100,000 ants. There are three castes of ant. The workers (all female) which live for about a year, maintain the nest, look after the queen and her brood and do not reproduce. The queens which can live for up to fifteen years and produce young. The males only live for a few days or weeks after they are produced in spring as their sole purpose is to mate with the queen. Hundreds of male ants will swarm at the same time and many of them will die without mating at all. I feel like the males have got the short end of the stick in the ant world. But it’s not all doom and gloom, because the birds benefit greatly from this sudden influx of food.
Wood ants are now much scarcer than they used to be in Scotland, mostly due to intense forestry practices, use of pesticides and degradation of ancient forests. The conservation work that the RSPB is doing here at Abernethy to expand and restructure the woodland will benefit the wood ants greatly in the future and help their populations to increase and expand into new areas. Next time you are out for a walk in the forest, keep your eyes peeled for these little guys (or more accurately, girls). There are hundreds of wood ants nest all over the Abernethy reserve. You can find a HUGE one on the Two Lochs trail that goes past Loch Garten and Loch Mallaichie. To help you find it, you can get a free trail map from the Osprey Centre next time you visit!