Late last October I found a Lasius claviger queen. After hibernation, I introduced her to host workers I found in a park in Sioux Falls. The workers are dark brown and unusually large, unlike any neoniger, americanus, crypticus, or pallitarsis workers I've seen. After studying the Lasius niger page and Key to North American Lasius species on AntWiki, I believe they are Lasius niger, which are confirmed invasive to North America but not confirmed to be present in South Dakota.
Title:
1. Location: Sioux Falls, SD
2. 5/14/'25
Body:
1. Location of collection: City park, Sioux Falls, SD
2. Date of collection: 4/21/'25
3. Habitat of collection: A small bluff near a creek, deciduous forest
4. Length: 3.5 - 4.5 mm, depending on how physogastric they are
5. Coloration, hue, pattern and texture: Dark brown, with head being darker than the gaster. Body shape looks like a cross between L. neoniger and L. americanus.
8. Nest description: Under a stone
According to the key...
- Medium to dark brown; penultimate and terminal basal teeth of worker subequal in size, gap between them has about the same area as terminal tooth and is constant in shape; occurring in mesic sites . . . . . Lasius niger
My phone camera isn't the best, yet from the picture I was able to get, the teeth best line up with Lasius niger. Again, I can't tell 100%, but the penultimate and terminal teeth look the same size, especially when compared to the images of neoniger, americanus, pallitarsis, and crypticus, which have a long, hook-shaped terminal tooth not present in this specimen. Furthermore, the round head shape fits best with Lasius niger.
Edited by RushmoreAnts, Yesterday, 12:34 PM.
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