Other Common Names
Winter ant, in reference to its foraging at temperatures barely above freezing during the cooler months. False Honey Ant is an unfortunate name, since the storage product in the corpulent young workers of these ants is fatty, not sugary.
Synonyms and other taxonomic changes
Currently only one species recognized in this genus in North America, but several varieties and subspecies have been described, and some may eventually prove to be valid species.
Explanation of Names
Prenolepis - inclined (petiolar) scale
imparis - mismatched, referring to the disparity in appearance of winged males and females.
Body lengths: worker 2.5-3.5mm, queen about 8mm, male 3-4mm
mandible triangular, with 5 or 6 teeth (rarely 7); in dorsal view, mesonotum severely constricted giving the mesosoma a distinctive hourglass-like shape; dorsal surface of mesosoma smooth and very shiny
head, thorax, and abdomen very dark brown; legs and antennae of live specimens medium brown at base, smoothly shading to pale yellow at tips (this color arrangement gives the overall impression of an insect that is very dark in the middle, and very pale at the extremities)
most of the United States, plus southern Ontario and Mexico
Usually nest in the soil with some clay content (but variety testacea lives in sand) in wooded situations or occasionally constructing a chamber under a rock or log. This ant is often associated with oak woodlands of various sorts (or scrub oak thickets in the west), but also (beech-)maple.
Often build their nests deep underground, staying inactive during the summer months, and returning to activity when the weather cools. The earliest flying of our cool climate North American ants. A few other, non-native species fly in winter months in subtropical southern Florida or Texas.
Workers feed on honeydew, secretions of floral and extrafloral nectaries, sap flows, exudates from galls, earthworms and arthropods (usually as carrion), and ripened or decaying fruit.
Males and females are reared in late summer, then overwinter in the underground nest, and are among the first of ants to take their nuptial flights in the spring.
Young workers are "overfed" and swell with fat, from which a nutritious glandular secretion is produced that is the main food upon which the year's single brood of workers and alates is reared. After this corpulent stage, the storage workers lose weight and sclerotize to become the forager (temporal) caste.
One of the few ants specialized for cold temperature foraging; they can be found foraging even at near freezing temperatures, where they are often the only ants visibly active. However, their range does not extend into the far north, despite their cold tolerance.
Viewing Prenolepis from above should immediately reveal the distinctive hourglass-shaped mesosoma, a distinguishing feature of the genus, and the anteriorly broad then tapering gaster.
overview of genus
and the single nearctic species (Kye Hedlund, U. of North Carolina)
close-up images of pinned adults
from various angles (AntWeb, California Academy of Sciences)
rank=species&name=imparis&genus=prenolepis&project=calants" class="bb_url">pinned adult image
plus several comparison thumbnail images of other genera (AntWeb, California Academy of Sciences)
pinned adult image
(Insects of Cedar Creek, Minnesota)
pinned adult images
(Tim Linsvayer, Carleton College, Minnesota)