HYMENOPTERA | Ants

APOCRITA | Aculeata > Formicidae

Ants are taxonomically classified together with bees and non-parasitic wasps within the Aculeata (stinging species) subdivision of the hymenopteran suborder Apocrita. There are somewhere in the region of 15,000 identified ant species worldwide, all within a single family Formicidae, which is broken down into numerous subfamilies.

In Britain we have around fifty native species; a number of which are common, some that are regarded as scarce or rare dependent on where you live, and a few that have dubious status or may even be extinct. They are separated into four subfamilies, Dolichoderinae, Formicinae, Myrmicinae and Ponerinae with virtually all the species that are likely to be encountered in the three main genera; Formica, Lasius and Myrmica, as described below.

My interest is with the species that are known to occur locally in East Dorset and the New Forest. There are quite a few, so I compiled a list and came up with twenty target species; eleven in subfamily Formicinae (Formica x5 and Lasius x6), seven in Myrmicinae (Myrmica x5, plus a couple of nationally scarce species in other genera) and one other scarce species in Dolichoderinae. I certainly don't expect to find all of these, but it's always useful to have some knowledge of the species that may be seen.

Of course, we have the usual problem encountered with most invertebrate groups, in that ants are very difficult to identify from photos. So, whilst the individual 'species accounts' connected to the following thumbnails have been written with care and should be accurate, the associated photos purely represent my best attempt at id's. In some cases, I may have sought advice but, understandably, there's a reluctance to confirm a species unless certain. I have made qualifications where appropriate and have tried to ensure that where an individual can only be regarded as 'likely' the photo is captioned accordingly.

In this respect, it's also worth noting, that in addition to trying to understand the morphological differences between similar species, 'likely' candidates can very often be determined, or at least narrowed down, by their habitat and, in some situations, from their nest and/or general behaviour. I like to take all these factors into account before confirming a name.

Formicinae

Formicine species have a single node-like segment called the 'petiole' that connects the thorax to the abdomen or, to be more precise, the mesosoma to the gaster. The mesosoma is the middle portion of the body incorporating the thorax and the first fused segment of the abdomen. In ant-language, it's more commonly referred to as the 'alitrunk'. The gaster is the bulbous portion of the metasoma; the posterior part of the body less the abdominal segments in the petiole. In the case of formicine ants, the gaster begins with abdominal segment S3. It is smooth without constrictions and has five visible segments when viewed from above. At the tip of the gaster there's a small circular opening called the 'acidpore' from which these particular species are able to spray formic acid. They do not possess a functional sting, instead having venom glands for protection when threatened or defending their nests.

We have twenty-five species of formicine ant in two genera, Formica and Lasius, (excluding Plagiolepis which is only found in the Channel Islands). In general terms, Formica ants are medium-sized and relatively robust, averaging around 5-10mm; most have a large and rounded gaster, and are dark or red-brown in colour. Lasius species are smaller, typically in the region of 3-5mm, and are mainly black, plain brown or yellowish brown. Body length refers to the workers as males and queens are rarely seen.

Some feed on nectar, whilst others are general scavengers foraging on the ground or in vegetation. Nests are often large with hundreds, if not thousands, of sterile female workers attending and caring the eggs and larvae. See below for further general information, particularly relating to wood ants.

Formica fusca

Large Black Ant

Lasius flavus

Yellow Meadow Ant

Lasius cf.alienus

Chalk Ant

Formica rufa

Southern Wood Ant

Lasius niger

Small Black Ant

Lasius cf.psammophilus

Small Sand Ant

Formica sanguinea

Blood-red Slave-making Ant

Lasius platythorax

Humid Ant

Lasius sp.

Unidentified Species

So, apart from obviously wanting further photos of many of these species, and some more interesting and varied shots, I still have three further target species that I'd like to find. They are:

Formica cunicularia - a local, medium-sized, active species that's rather like Formica fusca, but is shade-intolerant and most likely to be found on coastal or near-coastal heaths and downland.

Formica picea - a local very scarce species, known as the Black Bog Ant, which nests in grass tussocks on marshy ground in the New Forest and on some wet heaths around Wareham.

Lasius fuliginosus - a widespread, primarily southern, although locally uncommon, shining glossy black species, known as the Jet or Jet-black Ant. It's an over-looked species most likely to be found foraging above ground in hedgerows or mixed scrub with some trees and bushes.

Myrmicinae

Whereas the formicine ants have a single node-like connecting segment between the mesasoma and the gaster as previously described, myrmicine workers are characterised by having two, the petiole and the postpetiole, both of which are very distinct. The postpetiole is a constriction of abdominal segment S3, so in the case of these species the gaster begins with S4. The first segment that's fused to the thorax is known as the propodeum and, in many species, there are propodeal spines that can assist with identification. Another useful feature when trying to identify some of these species is the construction of the antennae, particularly the shape at the base of the scape. It should also be noted that the females of most species retain a functional sting.

There are around thirty species on the British List in a dozen or more genera, the most relevant being the Myrmica 'red ants’ with twelve species. Nests and colonies are generally much smaller than those of formicine ants. They are permanent and, rather than being constructed in the open, are in soil, rotting wood, under stones or even in trees.

Myrmica rubra

Red Ant

Myrmica ruginodis

Woodland Red Ant

Myrmica cf.sulcinodis

Dark Red Ant

Myrmica sp.

Unidentified Species

Other species from my somewhat ambitious target list include:

Formicoxenus nitidulus - a rather small, uncommon local species, known as the Shining Guest Ant, that has small colonies inside Formica rufa nests. Although the species has been recorded locally it is difficult to find due to its size and the fact that it spends most of the time in the host nest, although individuals may be found on the mound surface on warm, dull, humid days - a case of being in the right place at the right time!

Myrmica sabuleti - a widespread, apparently fairly common in the south, reddish-brown species associated with chalk downland and sandy heaths, so hopefully one that I should be able to find.

Myrmica scabrinodis - a common reddish yellow to dark brown species that typically favours open grassy locations rather than woodland; a species that I'm surprised I haven't yet seen.

Temnothorax interruptus - a rather small, rare, pale yellowish, local coastal species, added to the list as a challenge!

Tetramorium caespitum - another small local species, known as the Turf Ant, again added to the list as a challenge as it has been recorded from the New Forest and Dorset heaths.

Some general life cycle information, typical of Wood Ants

Only queens lay eggs. Eggs hatch into larvae and undergo a complete metamorphosis to become adults, the caste of which is dependent on larval development, diet and whether the egg was fertilised. Workers stem from a fertilised egg, and are always female. Young workers deal with brood care and looking after the queen. Later, as they age, their time is mainly involved with nest maintenance. Older workers forage for food. Most live for about a month, unless they overwinter with the queen. The queen can live for a decade, and in polygynous nests where they succeed each other, the colony can survive for several decades. Males stem from unfertilised eggs and only live for a short time after they emerge, dying shortly after mating with one of the emerging virgin queens – this nuptial flight is an event that’s confined to a short window of just 2-3 weeks usually between June to August subject to conditions. The newly mated queen will shed her wings and then disperse to try to establish a new colony.

Original list created Nov.21 | updated Jan.23 (v.3)