bring their prey. Not all are predators: the South

American leaf-cutter ants form huge colonies with

subterranean fungus gardens, where they bring

slices of leaves to rot and grow the fungi that they

consume. They can defoliate whole trees.

Ant colonies represent a great opportunity:

safe, climate controlled, full of stored food and ant

larvae, but any beetle taking advantage of them

needs to get past the ants. Beetles of several

families have developed a suite of adaptations—

above | Limulodes (Ptiliidae)

Featherwinged beetles, these

from the USA, act as cleaners

in ant nests, eating fungi

and spores.

chemical and physical—to persuade ants

to ignore them, mistake them for

food, or even welcome them as

nest mates, as well as other

adaptations such as

shortening of limbs and

antennae, and fusing

of abdomen segments,

to protect them from

damage during rough

handling by the ants.

Animals that have

adapted to live with ants

are called myrmecophiles

(ant lovers) and can be

recognized by characteristics

including clumps of setae called

trichomes that provide food or

chemicals to the ants, fused segments,

short antennae, sometimes loss of pigmentation

or eyes, and, in some extreme cases, structures

that allow the ants to pick them up and carry

them without damage. We can even see such

characters in fossils, and can assume they must

be myrmecophiles without knowing their

actual biology.

Hundreds of species of beetles of many

families have become myrmecophiles, the most

common of these being Histeridae, Carabidae:

Paussinae, some Scarabaeoidea, and particularly

Staphylinidae of the subfamilies Aleocharinae

and Pselaphinae. The Pselaphinae tribe

Clavigerini are almost all compulsory ant

associates. Some myrmecophiles are scavengers

or cleaners, while others consume the ants’

resources, and a few eat the ants themselves

as well as their larvae.

opposite | Paussus

(Carabidae: Paussinae)

This highly modified ground

beetle, almost unrecognizable

compared to its surface-living

relatives, has many chemical

and physical adaptations in

order to survive in ant nests.