HYMENOPTERA > APOCRITA | Aculeata > Formicidae > Myrmicinae > Myrmicini

A variably coloured reddish-brown ant, with a longitudinally rugose sculptured head, mesosoma and pedicel. Individuals in some colonies are lighter and, to my eyes, better described as brownish-red. The species is very similar to Myrmica rubra, but can be distinguished by the shape of the petiole and the length of the propodeal spines.

The forward part of the junction between the petiole and postpetiole has a notched appearance, best seen in profile, where the flat-topped petiole has a sharp step down at the rear, rather than the smooth transitional curve seen in Myrmica rubra. Although the shape of the petiole is important, it is often difficult to determine from photos particularly when taken from above, so it's necessary to have a good view of the propodeal spines that are noticeably longer and slenderer, and with the length being greater than the gap between the tips. The area between on the propodeum has ridges across it.  

The antennal scapes have the same gently curve at the base as seen in Myrmica ruba as opposed to the more sharply bent base found in some other Myrmica species such as Myrmica scabrinodis and Myrmica sabuleti, which I have not yet seen.

Workers are a tad larger than those of Myrmica rubra averaging 5-6mm. Colonies can be either monogynous or polygynous. In monogynous nests, the single reproductive queen will be marginally bigger than the workers and larger than the smaller queens, known as 'macrogynes', that are found in polygynous colonies where there may be several interconnected nests. The nests may be directly in the ground, in tussocks, under stones or against or under tree stumps. Nest density can be high with several hundred workers. The workers forage both on the ground and in vegetation where they will hunt small invertebrates such as aphids or small flies, as well as feeding on honeydew. They are very aggressive and will ferociously defend their nests but, unlike Myrmica rubra, are less likely to sting. They are also fairly slow moving and curious, which makes them good photographic subjects.   

Myrmica ruginodis is common and widespread across Britain including the Scottish islands where in Shetland it's the only recorded ant species. It occurs in many habitats including heaths and moors, wetlands, parks and gardens but, particularly in the south where it is shade-tolerant, is most frequently found in woodland.