A pair of Adetomyrma goblin dracula ants groom a larva. Madagascar; captive lab colony photographed at the California Academy of Sciences

Brachymyrmex patagonicus is a South American rover ant that is spreading rapidly across the southern and western United States. Here, workers feed from a honey bait. Tucson, Arizona, USA

Formica obscuripes nestmate workers engaging in trophallaxis, or the social sharing of liquid food. Wisconsin, USA

Nestmate transport in Camponotus nigriceps sugar ants. It is thought that ant colonies conserve energy by having one worker do the walking for two. Yandoit, Victoria, Australia.

Lioponera ruficornis

A tight column of black raider ants departs on an afternoon raid. Diamond Creek, Victoria, Australia

Lioponera ruficornis

A column of sleek Lioponera ruficornis. Notice that most of these ants carry small red mites on their bodies. Diamond Creek, Victoria, Australia

Alarm posture in a Crematogaster emeryana acrobat ant, gaster held high and sting extruded. Crematogaster ants do not actually use their stinger to sting; rather, the organ is instead employed as a brush to broadcast volatile chemical signals to nestmates and to smear defensive chemicals on attackers. Chiricahua Mountains, Arizona, USA

Ochetellus worker recruit to food. Ants in this subfamily often arrive in large numbers to resources, maintaining trails between their nest and persistent food source. Diamond Creek, Victoria, Australia

Major and minor workers of the turtle ant Cephalotes pusillus engage in trophallaxis food-sharing behavior. Carrancas, Minas Gerais, Brazil

Along an arboreal trail in South Africa, Crematogaster castanea tricolor nestmates exchange a bit of food. St. Lucia, KZN, South Africa

Sonoran desert cacti are frequently covered in ants. Cacti provide ants with nectar- a ready food supply in a harsh environment- in exchange for protection from herbivorous insects. Here, two Crematogaster opuntiae acrobat ants exchange nectar they have gathered from a chain-link cholla. Tucson, Arizona, USA

A subterranean trail of Dorylus helvolus. St. Lucia, KZN, South Africa

Eciton burchelli army ants can form living bridges with their bodies. Captive colony at the California Academy of Sciences

Eciton hamatum workers return from a successful raid bearing captured ant brood. Jatun Sacha reserve, Napo, Ecuador

Eciton burchelli army ants. These large, predaceous ants are ubiquitous in the rainforests of Central and South America. Captive colony at the California Academy of Sciences

Eciton burchellii workers returning from a raid. Maquipucuna reserve, Pichincha, Ecuador

Eciton hamatum Jatun Sacha reserve, Napo, Ecuador

A trail of Argentine ants, Linepithema humile. Davis, California, USA

Formica obscuripes nestmate workers engaging in trophallaxis, or the social sharing of liquid food. Wisconsin, USA

Monomorium dichroum

Panama City, Panama

Monomorium pharaonis

Friend or foe? Two Monomorium pharaonis worker ants briefly touch antennae along a pheromone trail. Icononzo, Tolima, Colombia

A busy trail of Monomorium pharaonis pharaoh ants. This species is now among the most pesty house-inhabitating ants worldwide. Icononzo, Tolima, Colombia

Neivamyrmex melanocephalus army ants initiating a live-ant bridge with their own bodies. Here two ants lean against each other while a third starts to climb. Sycamore Canyon, Arizona, USA

Neivamyrmex opacithorax. Army ants carrying brood. Notice how the ants carry their pupae, slung under their bellies in typical army-ant style. Chiricahua Mountains, Arizona, USA

Oecophylla smaragdina, the green tree ant of northern Australia. Cape York Peninsula, Queensland, Australia

Friend or Foe? Oecophylla longinoda workers encounter each other on a tree branch and take a quick sniff of the other's scent. St. Lucia, KZN, South Africa

Nestmate transport in Oecophylla longinoda weaver ants: a major gives a lift to a minor worker. This form of transport is thought to be more energy efficient than if both ants were to walk individually. St. Lucia, KZN, South Africa

Oecophylla longinoda patrol a tree trunk. St. Lucia, KZN, South Africa

Formica obscuripes nestmate workers engaging in trophallaxis, or the social sharing of liquid food. Wisconsin, USA

Mesoponera elisae

Follow the leader! Here, Mesoponera elisae workers engage in "tandem running" behavior, where a leading ant paves the way for a nestmate to follow. Notice the following ant's antennae making tight contact with the abdomen of the lead ant. St. Lucia, KZN, South Africa

Among the most damaging pest ant species is Solenopsis invicta, a fire ant native to South America. This species has been accidentally imported to the southern United States, eastern Australia, China, and elsewhere. Here a worker fire ant is shown in stereotypical defensive posture, her sting extruded, waving a droplet of venom in the air. Austin, Texas, USA

Her nest disturbed by the photographer, a Solenopsis thief ant worker exudes a droplet of venom on her stinger and waves it in the air. This behavior is known as "gaster-flagging". Morretes, Paraná, Brazil

Nylanderia sp. recruiting in large numbers to an insect carcass. Cape York Peninsula, Queensland, Australia

A Simopelta queen with attendant workers running in a column. Her abdomen apparently exudes an attractant that keeps the attention of the following ant whose mouthparts are held open above abdominal segment 4. Parque Nacional Henri Pittier, Venezuela

Two nestmates of the odorous house ant (Tapinoma sessile) share a granule of sugar. Champaign, Illinois, USA.

Friend or foe? Two Wasmannia auropunctata meet on a foraging trail and briefly assess each other. Ants from different colonies will attack each other, but these two are nestmates and let each other pass. Gamboa, Panama

Friend or foe? Two Wasmannia auropunctata meet on a foraging trail and briefly assess each other. Ants from different colonies will attack each other, but these two are nestmates and let each other pass. Gamboa, Panama

Technomyrmex jocosus, trail on Eucalyptus trunk. Nhill, Victoria, Australia