For some time we believed we only had the one species of black ant in the garden, Lasius niger (Black Garden Ant), however in August 2022 we noted several garden ants attacking a much larger and much blacker ant (see below) and we realised we probably had two species.
The above scrap between the more numerous Garden and the lone Jet ant went on for some time, indeed we got bored after 10 minutes and left them to it. However going back over past videos we realised many of them contain Jet Black ants and not Garden ants as we believed at the time.
The video below shows Jet Black Ants attending aphids which provide a source of honeydew to the ants in return for their protection. However you will also notice that many of the aphids are dead. The sepia colour they turn is part of the reason they are called Mummy aphids.
Their deaths were the result of an ichneumon wasp laying her eggs within the live aphids, clearly the ants cannot always guard their charges against such an attack. The developing wasp larvae eats its way clear of the aphid which often swells and turns a light brown husky ‘Mummy’ colour.
So how do you tell a Jet Black Ant, from a Garden Ant when you don’t have one of each stood next to one another for a size/colour comparison. The easiest, although not fool proof way is to look at the back of the head. In Garden Ants the back of the head is relatively straight (left below), where as in the Jet Black Ant it is clearly concave (right below) or heart shaped.
Another incident with Jet Black Ants occurred on 10th September 2021 when we accidentally severely damaged, partially destroyed a large Jet Black Ant nest which had established within a compost bin we had been using to store a large pond liner off cut. Thankfully the nest wasn’t within the part of the off-cut we were looking for and we were able to put everything else back as close to how we found it as possible.
As can be seen from the photographs below, this was clearly a Jet Black Ant nest, the female worker shown below running with a larva, clearly has the distinct concave head shape. By the way the image on the left below shows the larva, not the preceding egg stage. It is the larval stage that sees the only growth phase the ant will undergo. Following from the larval stage will be a pupation stage, before the fully formed adult ant emerges.
The rather poor video below, again of Jet Black Ants, shows what we now believe to be trophallaxis, which is when on worker ant feeds another via regurgitation of sugary liquid. This can often arise due to the different roles workers undertake for the colony. Not all workers venture outside the nest to forage for food. Those that do, often store liquid food in a gizzard and feed their nest bound co-workers.