Due to their large number and diversity, myrmecophilous rove beetles occupy an array of behaviors. Myrmecophilous interactions can be generalized into categories, in three of which staphylinids can be found. The synecthrans, or “persecuted guests,” the synoeketes, or “tolerated guests,” and the
symphiles, or “true guests.”
Synecthrans Synecthran staphylinids live on the periphery of the host colony and are not accepted into the colony. The majority are in the subfamily Aleocharinae, having defensive glands on their terminal abdominal segments. Species in this group, such as those in the genus
Pella, commonly lay their eggs in the refuse heaps of their host ant, where the larvae feed on the discarded carcasses of ants. If detected by the host ant, the larvae enters a typical defense position, facing the ant with its abdomen tip raised. Usually this behavior results in the ant palpating the beetle's abdomen and stopping the attack. At least two members of
Pella, P. funestus and
P. humeralis, produce several of their host ant's alarm pheromones to avoid aggression. Other species, like members of
Myrmechusa, Aenictonia, and
Anommatochara, prey on raiding columns or on the nests of driver ants (
Dorylus).
Myrmechusa species attack the ants from the rear before pulling them from the main column. If pursued, they rapidly wave their abdomens through the air, releasing a noticeable scent. Ants encountering this scent seem disoriented and take almost 20 minutes to recover.
Synoeketes Synoeketetic staphylinids live in close contact with their host ants but are not integrated into the colony. These species may be further categorized as neutral, mimetic, loricate, and symphiloid synoeketes. Neutral synoeketes ignore and are ignored by their host, but feed on refuse. There are few staphylinid neutral synoeketes, but some are found in the genus
Athetini, which live in the debris and fungal chambers of leaf cutter ants (
Atta). Syneoketes generally live on or inside of ant nests, where they feed on refuse and may steal food from their hosts. There is some overlap between synoeketes and other categories, especially in loricate species and synecthrans, and symphiloids and symphiles, where the behavior of “true guests” may be difficult to determine.
Symphiles Symphilic staphylinids have been fully integrated into the host ant's society. Symphilic species have undergone complex morphological adaptations, many becoming myrmecoid. Most have developed trichomes, which secrete appeasement pheromones. The most extreme adaptations, found in members of tribe Clavigerini, include the reduction of mouthparts for
trophallaxis and the fusing of many body and antennal segments. While most symphiles use antennal contact to stimulate food giving from their host, at least one member of Clavigerini,
Claviger testaceus, secretes a chemical to induce regurgitation from its host ant
Lasius flavus. Symphiles typically take on many roles in the colony, raising young, feeding and grooming adults, and helping transport food and larvae. Many staphylinids are capable of following ant pheromone trails, although they are not limited to following trails laid by their host ant. This allows symphiles of army ants to migrate with the colony. Most species are
kleptoparasites fed by members of the ant colony, often through
trophallaxis. Almost all species have also been observed feeding on the brood. Some of these species die if kept away from the appropriate ant colonies, and others lay their own eggs in ant brood galleries, effectively making them
obligate parasites. ==Chemical mimicry==