Identification
At first glance Formica sanguinea is similar in appearance to Formica rufa. It can be told apart by the brilliant red head and thorax of large sanguinea workers and the dull grey abdomen. Small workers are darker and more difficult to tell apart from rufa. Sanguinea is a fast moving species and doesn't bend its abdomen between its hind legs to squirt acid at a foe like most wood ants. Sanguinea is the only species of ant that has an indentation between its jaws which serves it's purpose in combat. Workers can reach 10 mm and longer in established colonies when food is readily available.
Diet
Formica sanguinea is a predacious ant species and will eat almost any insect it can get its mandibles around -along with any sweet substance it can find, it can often be observed 'milking' aphids.
Sanguinea, being a slave maker, will invade the nests of other ant species to collect as much protein as it needs in the summer months. Lemani, candida, rufibarbis, cunnicularia, rufa, aquilonia, lugubris, pratensis and exsecta will all be raided by sanguinea for their eggs, larvae, pupae and cocoons. Most often, sanguinea will take these back to their nest to consume.
Other species such as niger, flavus, scabrinodis and rugidnodis may also be raided but are less often allowed to mature into adult ants as they don't make very good auxiliaries because communication with sanguinea is often impossible.
Intelligence
Formica sanguinea is well renowned to take advantage of any situation. This is particularly true when its raiding other ant nests. F. sanguinea carries out slave raids against Formica fusca and its relatives (fusca, lemani, candida, rufibarbis, cunnicularia) and even against the much stronger red wood ants (rufa, aquilonia, lugubris, pratensis and exsecta) and steals their brood (eggs, larvae, pupae and cocoons). These hatch out in the sanguinea nest and the slave workers feed and tend the sanguinea queen and brood. Sanguinea colonies are often established by a mated female invading a nest of fusca or lemani and stealing a supply of cocoons. After the slave ants hatch they consider the sanguinea queen to be their own and look after her and subsequent brood.
Typical habitat
Formica sanguinea prefers to nest in sandy, sunny places, particularly in rotting tree trunks on the borders of established pine woodlands. Their colonies can grow to over 10,000 individuals in their natural environment but much stronger colonies can be established in captivity numbering over 20,000 individuals. In addition to these numbers, the nests usually contains slave or auxiliary ants which often number the same as their masters . Sanguinea will move to a new nest in dense foliage before winter to minimise the effects of frost and moisture.
Raiding
Formica sanguinea scouts go out during July and August and map the terrain for nests to attack. They lay pheromone tunnels back to their own nest which other pseudo scouts follow on the outward journey. Tandem signalling takes place with ants releasing aggregation pheromones right back to the sanguinea nest which causes more ants to come out.
These form into distinct groups and approach the target nest from apposing directions. They outflank it semi circularly and often surround it completely. Depending on the other species being raided, the defenders will often come out in their thousands and position themselves around their nest entrances to meet the threat. The sanguinea attack is made simultaneously from all directions when fusca ants are the target, but with rufa, they usually attack strongly from the opposite side to their own nest and position considerable forces between the two nests at some distance from the rufa nest. Eventually, the rufa flee with as much brood as they can carry right into the blockading sanguinea which wrestle the young off them.
Tags: Formica | sanguinea | Slavemaker
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