Formica ravida
Temperature
20–26 °C
Humidity
50–70%
Colony size
5,000–30,000
Queen size
8–10 mm
Worker size
4–7 mm
Hibernation temp
6 °C
Diet
Care Guide
Formica ravida is a fascinating and challenging species for experienced ant keepers, best known for its remarkable social-parasitic founding strategy. Unlike typical ants that raise their first brood independently, a newly mated Formica ravida queen infiltrates the nest of a related host species—often a member of the *Formica fusca* group—kills the resident queen, and uses the host’s workforce to raise her own offspring. The host workers continue to tend her brood, unaware that they are rearing the next generation of parasites. Over time, the host workers die off, and the colony becomes entirely composed of *Formica ravida* workers. Queens are moderately sized at 8–10 mm, while workers range from 4–7 mm. Colony size can eventually reach up to 30,000 ants, forming a populous and active nest.
Their diet consists primarily of insect protein, supplemented with sugar water and honeydew. They are eager hunters and excellent scavengers, readily accepting mealworms, fruit flies, and roaches. A constant supply of carbohydrates is essential to keep the colony energetic and growing.
Care difficulty
Keeping *Formica ravida* is considered advanced, primarily due to the complex founding process. Replicating social parasitism in captivity requires access to host workers—usually a colony of *Formica fusca*—or the use of a specialized “host introduction” technique. Even after founding, the colony can be skittish and prone to stress if conditions are not optimal. Hobbyists must have prior experience with other *Formica* species and a solid understanding of colony manipulation.
Housing
A formicarium with moderate to large chamber capacity is needed, as the colony will expand quickly once established. Temperature should be maintained between 20–26°C, with humidity levels of 50–70%. The nest area should have a gradient of moisture; one side kept slightly damp while the other remains dry. These ants are sensitive to light and vibration, particularly during the early stages, so place the setup in a quiet, darkened location. A generous foraging arena is recommended, as they are active foragers and will appreciate space to hunt and explore. Hibernation is mandatory—keep them at a cool 6°C for several months during winter to maintain a healthy annual cycle.
First days after purchase
Upon receiving your colony, whether it is a queen with a few host workers or a larger parasitic colony, place them directly into a pre-prepared nest with a small, quiet arena. Minimize disturbance completely for the first 48 hours. Ensure that fresh sugar water and a small piece of protein (e.g., a half-cricket) are available near the entrance, but do not open the nest itself. Observe from a distance; the ants will need time to accept their new environment. If the colony is in the parasitic phase, avoid adding new host workers immediately—allow the existing dynamic to stabilize first. Patience and a calm hand are the keys to success with this extraordinary ant.