formicidae

3

The deceptive and tricky Ant-mimicking Crab-spider

There is no doubt that certain species of spiders are quite deceptive and tricky. This is the case of Aphantochilus rogersi (top photo), a neotropical carb-spider in the Thomisidae Family, that convincingly mimics its prey, the turtle ant Cephalotes atratus (middle and bottom photos) or also Zacryptocerus pusillus.

These spiders do not just mimic the appearance of the ant, but also oviposit in close proximity to nests of the model ant. As if that were not enough, Aphantochilus rogersi also has an specialized hunting behavior, this spider uses the bitten and paralyzed ant as a shield, presumably protecting it from attacks by living ants.

So, just in case, the next time you see an ant …. You better count how many legs it has. 

References: [1] - [2]

Photo credit: [Top: ©Pablo Sebastián Padrón | Locality: Pastaza, Ecuador] - [Middle: ©Ricardo Solar | Locality; unknown]  -  [Bottom: ©Ana Jaramillo | Locality: Riomanso Natural Reserve, Colombia]

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Relentlessly, the loathsome thing clambered upwards until it had settled itself firmly on neck and shoulders. The two antennae reached down my cheeks, gripping the corners of my mouth and clamping themselves there… And as I fought to unseat the inhuman rider perched on my shoulders, I knew what I was… I was an inferior animal being conquered, beaten, trained by a superior one.’

Damn right you were. Arthropod master race 4 lyfe.

2

Meat Ant (Iridomyrmex purpureus)

Also known as the Meat-eater Ant or Gravel ant, the meat ant is a species of rainbow ant (Iridomyrmex spp.) that occurs throughout Australia. Like most ants meat ants live in large underground nests that number around 64,000 individuals. Despite what their common name might suggest meat ants are omnivorous scavengers and will forage diurnally for whatever they can manage. Their common name comes from the fact that they are commonly used to clean carcasses. Interestingly meat ants do not have dedicated soldier and worker casts, instead they exhibit age caste polyethism which means they take on different roles in the colony at different ages. Young ants typically care for eggs and older ants form foraging parties.

Classification

Animalia-Arthropoda-Insecta-Hymenoptera-Formicidae-Dolichoderinae-Tapinomini-Iridomyrmex-I. purpureus

Image(s): Fir0002 

The feared and fascinating Jack Jumper Ant - the metazoan with the lowest possible number of chromosomes

The Australian Jack Jumper Ant, Myrmecia pilosula (Formicidae), with its 12 mm length, large eyes, and long mandibles with teeth, is an aggressive ant with a very potent sting. 

The sting is not severe (in terms of pain), but this ant is responsible for greater than 90% of Australian ant venom allergy. In Tasmania stings by M. pilosula (and possible the Inchman ant, M. forficate) caused 21–-25% of the 324 cases of anaphylaxis treated with adrenaline in the Royal Hobart Hospital Emergency Department between 1990 and 1998, compared with 13% caused by honeybee stings.

Moreover, what I personally find fascinating is the fact that ants of the Myrmecia pilosula species complex include some individuals with the lowest possible metazoan chromosome number of 2n = 2, although others in this cluster of sibling species have much higher numbers, the known maximum being 2n = 32.

If we also consider that males are haploid (they have a single set of chromosomes in the nucleus of their cells), as in other Hymenoptera, the somatic cells of males contain only a single chromosome.

Other common names: Jumper Ant, Hopper Ant, Jumping Jack, Bull Ant.

References: [1] - [2] - [3]

Photo: ©Arthur Chapman

Locality: Falcons Lookout Track, Werribee Gorge State Park, near Ballan, Victoria, Australia 

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“Pirate Ant” (Cardiocondyla pirata)

…a species of Myrmicine ant that was discovered in the province of Laguna in the Philippines. C. pirata gets its common name from the black steak that occurs across the eyes of females, this pattern occurs in no other ant and is thought to be reminiscent of a pirate’s eye-patch. C. pirata was discovered fairly recently (~2013) and as such very little is known about its biology. It likely behaves fairly similarly to other members of the genus Cardiocondyla

Classification

Animalia-Arthropoda-Insecta-Hymenoptera-Formicidae-Myrmicinae-Cardiocondyla-C. pirata

Image: Seifert B, Frohschammer S

Meranoplus mayri

…a species of Myrmicine ant that is distributed throughout the drier regions of Madagascar from the Southwestern region Andohahela National Park north into the province of Mahajanga. Meranoplus mayri are typically encountered at elevations of 20-1,345 m above sea level. Not much is known about the biology of M. mayri except that it is commonly found in urban gardens, grasslands, and deciduous and spiny forests. They are also thought to possibly occur in the High Plateau region as well. 

Classification

Animalia-Arthropoda-Insecta-Hymenoptera-Formicidae-Myrmicinae-Meranoplini-Meranoplus-M. mayri

Image: © AntWeb.org

5

Acacia, A Hairstreak and Ants: An Amicable Association

It is well-known that ants entertain all sorts of relationships with other invertebrates and even cultivate fungi: one of these relationships is that between ants and many lycaenid butterfly larvae.

The Lycaenidae is a large family of butterflies, second here in Victoria-Australia, only to the skipper family Herperiidae, but globally to the Nymphalidae reflecting the importance of this latter group in the tropics. The adults of many species are commonly known as ‘blues’ or ‘coppers’ indicating the importance of these hues to the overall colouration of the group.

Like almost all butterflies, lycaenids mostly feed relatively narrowly on a particular plant species or genus. In the case of the species shown here it is a wattle (Acacia), a tree/shrub genus that is diverse and widespread in the Australian region and also in Africa. In this case, the foliage of Silver Wattle (Acacia dealbata) is visible in the third picture.

The ants in these images are certainly not attacking or trying to eat the lycaenid larva, rather they are attending it. Glands on lycaenids are known to produce food that the ants harvest (like sugar and protein-based substances) and potentially also chemicals that pacify the ants. The ants, as a result, will tend the larvae and protect it from predators that otherwise would be problematic.

The ant that is associated with the butterfly larva shown here (Silky Hairstreak - Pseudalmenus chlorinda zephyrus) is apparently a species of Anonychomyrma. Ross P. Field, in his lovely little book on Victoria butterflies, lists the attendant ant of this butterfly as Anonychomyrma biconvexa - although knowing something of ants, my limited knowledge doesn’t allow me to confirm whether the ant in my pictures is indeed that species. Not all lycaenids have ant attendants, some have only one, and others may be attended by a range of different species.

Is their anything better than entomology?

One of the Many Little Things Has Formicid-Friends!

2

Ant-mimic spider, Myrmecotypus rettenmeyeri, and Gold Carpenter Ant, Camponotus sericeiventris

Spiders of the genus Myrmecotypus  (Corinnidae) are known for being morphological and behavioral mimics of ants (ant-mimicry or mirmecomorphy). This genus currently includes nine species from the New World, which occur from the United States (one species) to Argentina (one species), but most (seven species) occur from Mexico to Panama.

Myrmecotypus rettenmeyeri (top-left), native to Panama, mimics the Golden Carpenter Ant, Camponotus sericeiventris (top-right and bottom) which occurs in the same habitat. 

In this case, the medial dorsal keel on Camponotus sericeiventris is mimicked by a medial dorsal band of hair on Myrmecotypus rettenmeyeri. The active behavior of this spider also accurately mimics the antennal movements in the ants, keeping the first pair of legs raised when stopping, and often moving about. Other similarity is that the black surface of both spider and ant has yellow or golden-white pilosity with high reflectance.

References: [1] - [2] - [3]

Photo credits: [Top: ©Jeremy Gatten | Locality: Altos Del Maria, Panama, 2012] - [Bottom: ©Seig | Locality: Lapa Rios Ecolodge, Osa Peninsula, Costa Rica, 2014]

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