The Highland Biological Recording Group

The Shining Guest Ant Formicoxenus nitidulus

Photo © Stewart Taylor.
The Shining Guest Ant Formicoxenus nitidulus is a little-known ant which lives only as a commensal in the mounds of the much larger wood ants Formica aquilonia and F. lugubris. It is on the UK BAP priority list. In Highland, it was known until recently from only from 3 hectads in Strathspey and one in S Skye, and had not been recorded here for over 20 years. As part of the HBRG Ant Atlas Scheme, this interesting ant is being targeted. Recent work has discovered it in four 10km squares in Strathspey (green), two of these with no previous records. It is clearly under-recorded, and you can help to correct this situation.
How to recognise it: The Shining Guest Ant is tiny - only 2-3mm long - but it is conspicuously shiny. It moves rapidly and confidently over the surface of the mound among the much larger wood ants. It can be confused with a close relative, the common and slightly larger Slender Ant Leptothorax acervorum, which is occasionally found on wood ant mounds, especially those which have few wood ants and are perhaps failing and close to abandonment. It is not safe, therefore, to assume that any small ant on a mound is the Shining Guest Ant. Conclusive proof can be had from the head, which is smooth and shining in the Guest Ant but dull and sculptured in the Slender Ant.

Shining Guest Ant - the head is smooth and shining .	Slender Ant - the head is dull and grooved.	Shining Guest Ant to scale with wood ant.
Photos from http://www.antweb.org © April Nobile.		Photo © Stewart Taylor.
Where to find it: The Shining Guest Ant lives only in the nest mounds of the two true wood ants we have in Highland. These mounds are easily recognised - the ant is much more difficult to see. Look carefully at the mound, concentrating on areas where the thatch is thinner or missing and the ants easier to spot. You may need to look at a lot of nests to find it - it may not be on more than 1 nest in 10 even in a good area. Records away from Strathspey are especially welcome.
When to find it: The wingless males of the Shining Guest Ant are visible on the mounds between late June and mid-September, and possibly outside that period. They are most likely to be seen on warm humid days. Winged new queens and workers will be seen much less often.
How to report it: If you think you have found the Shining Guest Ant please giving the date and place, a full NGR (10 figures if you have a GPS), and as good a description of the precise location of the nest as you can manage. A photograph showing the setting of the nest (so that it may be easily located) would help. Ideally, a specimen of one guest ant and of the host wood ant should be taken and sent to Murdo Macdonald, 'Tigh nam Beithe', Strathpeffer, Ross & Cromarty IV14 9ET. This will allow confirmation of the identity of the guest and the host.