It’s the little things

Recently certain little things keep popping up in conversation… ants. It’s a group I don’t know much about, but am becoming increasingly aware of just how interesting they are. We’re talking about huge and exciting group  encompassing an estimated 20,000 species living in groups of a few dozen to a few million individuals on every major landmass except Antarctica, surviving by farming fungus, gathering seeds, hunting insects or even reptiles, and creating amazing architectural structures.

The most recent thing that has brought ants to my attention is this story about the accidental destruction of a rare ant colony on Forestry Commission land in Scotland. It seems the land manager didn’t follow best practice and accidentally allowed a nest containing both hairy wood ants and shining guest ants to be destroyed. Maybe the manager didn’t realise they were there or that they were special? The damage is done, and hopefully lessons have been learnt to prevent something similar happening again. In the spirit of learning, I thought I’d try to find out a bit more about the species of ants who met their untimely demise and share it here. It seems like an interesting system with one big and bold species inadvertently supporting a small and sneaky one…

Hairy wood ants, Formica lugubris, are big, tough aggressive ants that form huge colonies. Their common name comes from the fringe of hairs near the eyes that differentiates them from other wood ants, but you’d need a microscope to get a good look at that. They are the largest British ants at around 1cm in length, and are fearsome predators that work together to take down prey much larger than they are – caterpillars, beetles, and anything else they can get their mandibles on. All this goes to feed the brood back at the nest, while the workers feast on honeydew which they collect from aphids. A hairy wood ant colony can contain 250,000 or more individuals. They build large mounds in sunny clearings using pine needles and other forest debris, which creates a thatch to protect the colony from rain and conserve heat. Having large, exposed colonies means that these ants need to be able to defend themselves, and if biting isn’t enough, they can also spray would-be attackers with formic acid. Due to changes in land management, hairy wood ants are listed as ‘near threatened’ on the IUCN red list. There’s a great article on the arkive website, some good clips of hairy wood ants on the BBC nature site, and a nice article on the Northeast Scotland Biodiversity website, which also mentions guest ants.

Information on shining guest ants, Formicoxenus nitidulus, is a little bit more difficult to come by. These tiny, shiny ants are only about 3mm in length. They may be cute, but they are social parasites, living inside wood ant nests, nicking their food and getting free warmth and protection. They form colonies of around 100 individuals in small spaces, like bracken stems, that the wood ants can’t access. The wood ants mostly seem to ignore the guests as they move freely throughout the nest. Rarely, wood ants will attack these tiny invaders, but release them quickly thanks to a defensive chemical barrier in the guest ant cuticle. It can be difficult to find guest ant colonies even by destroying and searching a wood ant nest (so don’t try!), but males can be seen on nest surfaces between August and November. Shining guest ants are listed as vulnerable on the IUCN red list. Check out this Arkive entry for more details .

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