Pseudacteon lontrae

A trio of parasitic phorid flies (Pseudacteon lontrae) hover over an ant nest (Linepithema oblongum) looking for targets. Termas de Reyes, Jujuy, Argentina

Pseudacteon lontrae

Wham! A parasitic phorid fly (Pseudacteon) plants her ovipositor between the abdominal sclerites of a Linepithema oblongum worker ant to lay her egg. The oviposition takes less than a second. The hapless ant will later be consumed alive by the developing fly larva. Termas de Reyes, Jujuy, Argentina

Pseudacteon solenopsidis

An Ant-Decapitating Fly (Phoridae, Pseudacteon sp.) attempts to separate a fire ant (Solenopsis macdonaghi) from her nestmates. Lone ants make easier targets. Parque Nacional El Palmar, Entre Rios, Argentina

Ophiocordyceps

This Camponotus worker ant has succumbed to an Ophiocordyceps fungus. The ant's death is peculiarly gruesome. In the early stages of infection the fungus takes partial control over the ant's brain, directing the ant to an area where the humidity is optimal for fungal growth. There, the ant bites down on a leaf vein, anchoring it in place. The fungus then kills the insect, consumes the tissues, and issues a fruiting body. Jatun Sacha reserve, Napo, Ecuador

This Camponotus worker ant has succumbed to an Ophiocordyceps fungus. The ant's death is peculiarly gruesome. In the early stages of infection the fungus takes partial control over the ant's brain, directing the ant to an area where the humidity is optimal for fungal growth. There, the ant bites down on a leaf vein, anchoring it in place. The fungus then kills the insect, consumes the tissues, and issues a fruiting body. Jatun Sacha reserve, Napo, Ecuador

Ophiocordyceps on Camponotus atriceps

Fungal hyphae begin to overtake the carcass of a Camponotus it has killed. Refugio Amazonas, Tambopata, Peru.

Silhouette of an Ophiocordyceps ant-killing fungus. Jatun Sacha reserve, Napo, Ecuador

The enlarged abdomen and shrunken head of this Odontomachus haematodus trap-jaw ant indicates she houses a massive mermithid parasite. These large nematodes infect ant larvae and result in stunted adults. Armenia, Belize

Breaking the abdomen of a parasitized Odontomachus haematodus trap-jaw ant reveals the mermithid nematode coiled within. These worms infect ant larvae and cause stunted adults. Armenia, Belize

Breaking the abdomen of a parasitized Odontomachus haematodus trap-jaw ant reveals a mermithid nematode coiled within. Worms infect the ants as larvae and result in stunted adults. Armenia, Belize

The swollen red abdomen and unusually shrunken head of this Cephalotes porrasi turtle ant suggests she is carrying a parasitic mermithid nematode. Armenia, Belize

An Ant-Decapitating Fly (Phoridae, Pseudacteon sp.) attempts to oviposit on a fire ant (Solenopsis macdonaghi). Parque Nacional El Palmar, Entre Rios, Argentina

One of the defenses fire ants (Solenopsis sp.) employ against parasitic phorid flies (Pseudacteon sp.) is to hide. It is thought that the effectiveness of the flies in controlling pest fire ant populations is due more to disruption of the ants' normal foraging behavior than to the parasitism itself. Parque Nacional El Palmar, Entre Rios, Argentina

A mating flight of Crematogaster cerasi acrobat ants provides a parasitic Pseudacteon fly (at lower right) an opportunity to attack. Urbana, Illinois, USA

Apocephalus sp.

Within minutes of exposing a Pheidole dentata nest, the parasitic phorid flies are so thick they are essentially tripping over each other to attack the ants. Brackenridge Field Lab, Austin, Texas, USA.

Apocephalus sp.

A parasitic ant-decapitating fly takes advantage of a Pheidole dentata nest disturbed by the photographer to plant her eggs in the exposed ants. Brackenridge Field Laboratory, Austin, Texas, USA.

Ant Lion pits

Sapelo Island, Georgia, USA

An ant (Camponotus tortuganus) attempts to climb out of an antlion pit. Archbold Biological Station, Florida, USA

An antlion (not visible) hurls sand at an ant (Camponotus tortuganus) attempting to climb out of the trap. Archbold Biological Station, Florida, USA