Subfamily Myrmarachninae

Family Salticidae 蠅虎科
Subfamily Myrmarachninae
蟻蛛屬
Ant mimicking spiders

The Family of Salticidae has 18 Subfamilies. Myrmarachninae is one of the Subfamilies.

Myrmarachne is a genus of jumping spiders which imitate an ant by waving their front legs in the air to simulate antennae. Some species also look strikingly like ants.
Spiders in this genus are commonly called antmimicking spiders, although there are many other spiders that mimic ants.

Myrmarachninae has 8 Genus :
1) Bocus Peckham & Peckham, 1892 — Borneo, Philippines (3 species)
2) Damoetas Peckham & Peckham, 1886 — Borneo, Australia (3 species)
3) Myrmarachne MacLeay, 1839 — worldwide (205 species)
4) Panachraesta Simon, 1900 — Sri Lanka (1 species)
5) Rhombonotus L. Koch, 1879 — Australia (1 species)
6) Ligonipes Karsch, 1878 — Australia, New Guinea (6 species)
7) Arachnotermes Mello-Leitão, 1928 — Brazil (1 species)
8) Belippo Simon, 1910 — Africa (7 species)

Myrmarachne assimilis is the only Myrmarachne species that resembles the aggressive weaver ant Oecophylla smaragdina, with which it lives in close contact. Cosmophasis bitaeniata uses chemical mimicry to be accepted by the same ant species. It is suggested that M. assimilis uses a similar technique. Thus, its ant mimicry is twofold: in visual appearance to trick predators, but also evading to be hunted by the ants themselves.[3]

Several spiders (eg., most Myrmarachne) undergo transformational mimicry: because the spiderlings are too small to mimic the ant species the adult copies, they use other ant species as a model.

The overall body of spider myrmecomorphs is much narrower than non-mimics, which reduces the number of eggs per eggsac, compared to non-mimetic spiders of similar size. They seem to compensate by laying more eggsacs in their lifetime.
Ant-mimics usually use their first or second pair of legs to fake ant antennae, such reducing the number of functional legs to six.

Sometimes, the sexes each mimic a different model. There are also spiders where several morphs occur, each mimicking a different morph of the model ant species, or different ant species. For example, light yellow to brown morphs of Synemosyna aurantiaca mimic Pseudomyrmex flavidulus and P. oculatus, while black morphs mimic P. gracilis and P. sericeus.

In Micrathena, only males and juveniles resemble ants. This may be mimesis rather than mimicry.

It should be noted that even within a closely related group of taxa ant mimicry might have originated several times independently. This is demonstrated in the Salticidae subfamily Ballinae

80% of spiders with Batesian mimicry mimic ants, comprising more than 100 species. Ant-mimicking spiders can be found in the following spider families:

There are Twelve spider families have species that mimic ants in the world. Eight families are found in Borneo Island.

	Ant-mimicking Spider Family :	Ant-mimicking Spider Species :
1	Araneidae	(e.g. Micrathena)
2	Corinnidae	(e.g. Apochinoma, Castianeira, Myrmecium, Corinna vertebrata, Mazax pax, M. spinosa, Myrmecotypus, Sphecotypus, Otacilia, Phrurolithus)
3	Dysderidae	(Harpactea hombergi preys on ants, behavioral mimic, not morphological)
4	Eresidae	(Seothyra schreineri males mimic small Camponotus castes)
5	Gnaphosidae	(e.g. Micaria, Callilepis nocturna)
6	Prodidomidae	(Myandra)
7	Linyphiidae	(Linyphia furtiva, Meioneta beata)
8	Oonopidae	(Diblemma donisthorpei mimics Wasmannia auropunctata)
9	Salticidae	(e.g. Agorius, Augustaea, Belippo, Bocus, Chalcolecta, Consingis, Corcovetella, Cosmophasis, Enoplomischus, Judalana, Leptorchestes, Martella, Marengo, Myrmarachne, Paradamoetas cara, Peckhamia picata, Philates, Sadies, Sarinda, Synageles, Synagelides, Synemosyna, Tutelina, Uluella, Zuniga)
10	Theridiidae	(e.g. Anatea formicaria, Cerocida strigosa, Coleosoma floridanum (only males), Coleosoma acutiventer, Helvibis brasiliana, H. chilensis, Heleosoma floridanum, Melychiopharis cynips, Cerocida strigosa)
11	Thomisidae	(e.g. Amyciaea, Aphantochilus, Bucranium, Strophius nigricans)
12	Zodariidae	(e.g. Storena, Zodarion)

Some spiders (e.g. Zodariidae or some Myrmarachne) use their ant disguise to hunt ants, although most use their disguise to escape predators. In salticids, the latter can be discerned from the ants from the movements they make in order to keep the ants at an acceptable distance. Ant hunters often do not resemble ants as much.

Ant mimicry is mimicry of ants by other organisms. Ants are abundant all over the world, and insect predators that rely on vision to identify their prey such as birds and wasps normally avoid them, either because they are unpalatable, or aggressive. Thus some other arthropods mimic ants to escape predation (protective mimicry). Conversely, some species (e.g. Zodariidae spiders) use their anatomical and behavioral ant mimicry to hunt ants (aggressive mimicry). Other cases are also known.[1] The term myrmecomorphy is also used to describe ant mimicry.

Ants are the most abundant group of insects and have powerful defense mechanisms such as acid taste, aggressive biting, painful sting, and group defense.
Ants are generally not subject to predation. They are the ideal models in mimicry rings. Many insects and spiders have different ways to resemble ants. This is known as Myrmecomorphy.

Myrmecomorphy highlights an important aspect of mimicry - the behavior. Predators use different aspects of prey appearance when making a decision to attack. Behavior is an important part of multi-modal signals. Constant waving of antennae is a common feature of ants. Ants are also characterized by their jerky and zigzag movements. Those ants behavior are commonly seen in the ant mimics.

The more common Mymarachne species have a long waist (pedicel) and an elongated cephalothorax with a constriction dividing the higher cephalic region and the lower thoraxix part. The jaws of Myrmarachne spider, especially the males, are enormously enlarged and project in front making the spider appear to be a soldier ant.
These Jumping Spiders assume the appearance of an ant by having long and slender legs. These spiders' fore-legs are often raised in the air like a pair of antennae of the ant.

By mimicking ants, the spiders deceive their ant-models and prey either on the ants themselves, or on the homopteran bugs "tended" by the ants.
And by copying the physical appearance of ants, the ant-mimicking Jumping Spiders are for self-protection, since spider-hunting wasps, birds and other spider-predators generally avoid ants which secrete the distasteful formic acid when attacked.
All images of Ant mimicry spiders in this page are taken in Sabah, Malaysia.