Bug FAQSlender Ant
Leptothorax acervorum · Order: Hymenoptera · Family: Formicidae
Workers are about 3 mm long and queens are roughly 10 % larger. They have a dark head and abdomen with a lighter middle body and are covered in hairs. They live in dry conifer forests, nesting in rotting wood, stumps or under bark across much of Europe from Spain and Italy to northern Scandinavia and Siberia.
Source: Wikipedia
How to recognize it
They have a two-tone appearance: a dark head and abdomen contrasted with a lighter mesosoma, and their body is covered with hairs.
Source: Wikipedia
Size
Workers measure about 3 mm in length, while queens are roughly 10 % larger.
Source: Wikipedia
Life cycle
Colonies are often facultatively polygynous, making them a model for studying multi-queen social structure. At the edges of their range they can also form single-queen colonies.
Source: Wikipedia
When you see it
In Spain they become active one to two hours after morning temperatures rise, and most copulations occur within the first two hours after females start calling.
Source: Wikipedia
Where it comes from
They are native across central, western and northern Europe, from central Spain and Italy up to the tundra-taiga zones of northern Scandinavia and Siberia.
Source: Wikipedia
Lookalikes
They are extremely similar in shape to other Leptothorax ants and share typical ant features such as elbowed antennae, metapleural glands, and a narrowed second abdominal segment.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: Alaska, Utah, Washington, Colorado.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do Leptothorax acervorum ants look like?
They have a dark head and abdomen with a lighter middle body and are covered in fine hairs.
Source: Wikipedia
Where are Leptothorax acervorum found?
They are native to much of Europe, from Spain and Italy up to northern Scandinavia and Siberia.
Source: Wikipedia
When are they active during the day?
In Spain they become active about one to two hours after the morning temperature rises, and most mating occurs shortly after females begin calling.
Source: Wikipedia
Do they live in colonies with multiple queens?
Yes, they often form facultatively polygynous colonies, which are used as a model for studying multi-queen social structures.
Source: Wikipedia
Same family (Formicidae)
Eastern Black Carpenter AntCamponotus pennsylvanicusCan bite
Red Imported Fire AntSolenopsis invictaCan sting
American Winter AntPrenolepis imparis
Argentine AntLinepithema humileNuisance, not dangerous
Immigrant Pavement AntTetramorium immigransCan sting
Odorous House AntTapinoma sessileCan damage your homeSources
- Wikipedia: https://en.wikipedia.org/wiki/Leptothorax_acervorum
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-26 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-26.