Jet Ant Lasius fuliginosus

Also known as Jet-black Ant.

One of the challenges I have faced with keying ants is that the keys differ between workers, queens and males, but the key doesn't tell you how to tell which is which! I think some of my earlier attempts were thwarted by a misunderstanding of ant biology leading to an erroneous assumption that a flying ant away from a colony is likely to be male, the female workers being unwinged and the queens remaining in the colony. But further reading suggests that I might also encounter future queens away from the colony and presumably these are female and will key as queens.

These four all had a projection from the bottom rear of the abdomen which I had a hard time reconciling with female apparatus so I assume they are all males. Certainly this looked very different to the next one I examined which I assume was a female.

winged male Lasius fuliginosus showing propodeal spiracle, genitalia and jaws, Wendling Beck Environment Project (Norfolk, UK), 9th August 2023

second winged male Lasius fuliginosus showing jaws, Wendling Beck Environment Project (Norfolk, UK), 9th August 2023

third winged male Lasius fuliginosus showing jaws, Wendling Beck Environment Project (Norfolk, UK), 9th August 2023

fourth winged male Lasius fuliginosus showing jaws, Wendling Beck Environment Project (Norfolk, UK), 9th August 2023

This one caused me more problems. When I initially looked at it I was undecided whether the propodeal spiracle was on the side face or not, but it certainly seemed to be elongate and slit-like. So I spent quite a lot of time trying to work out what species of Formica it was, eventually getting nowhere and putting it to one side to re-examine on a later date. This I did after examining the above individuals. The first thing I noticed was the very different structure at the rear of the abdomen - a round hole with no dangly bits other than a rim of hairs - surely a female! The next thing I noticed was that if you viewed propodeal spiracle from a different angle it looked round (and yes, it was definitely on the curved surface between the side and the rear). No wonder I couldn't get anywhere keying it as a male Fusca - it was a female Lasius! And as such it swiftly keyed to Lasius fuliginosus.

female Lasius fuliginosus showing abdomen tip, propodeal spiracle (from two angles) and wings, Wendling Beck Environment Project (Norfolk, UK), 20th July 2023