Acrobat Ant

Crematogaster lineolata — the lined acrobat ant — is one of about 500 species in genus Crematogaster (the acrobat ants — one of the largest ant genera worldwide). The species is widespread across all of eastern North America from southern Canada south through the eastern US to Texas. Workers are 3-4 mm long (small for a typical NA ant), with the species' diagnostic features that define the entire Crematogaster genus: unique 'HEART-SHAPED' ABDOMEN that is FLATTENED LATERALLY and POINTED AT THE TIP (the heart-shape is one of the most distinctive ant body morphologies in NA Formicidae and is the diagnostic field-ID feature for the entire genus); dark brown to black body coloration with darker abdomen; smooth body surface with fine sculpturing. The species is unlike most other NA ants in DRAMATICALLY RAISING the heart-shaped abdomen OVER THE BACK like a small flag when threatened or excited — the 'acrobat' name comes from this dramatic abdomen-raising display. The acrobat display: when colonies are threatened or excited (by colony disturbance, prey discovery, or contact with rival ants), workers EXTEND THE ABDOMEN UPWARD AND OVER THE BACK so the abdomen tip points forward toward the head — the heart-shaped abdomen is held vertically in a dramatic 'banner' position. The display is used for: INTRASPECIFIC SIGNALING (communicating colony alarm and defense recruitment to other workers), PREDATOR DETERRENCE (the dramatic acrobat posture makes the small ants appear larger and more threatening to predators), and PHEROMONE RELEASE (alarm pheromones from the abdomen tip are dispersed more effectively when the abdomen is held in the elevated acrobat position). The acrobat display is unique among NA ants and is one of the most-cited examples of arthropod display behavior. The genus Crematogaster is one of the most ecologically dominant ANT GENERA in tropical forest canopies — many tropical Crematogaster species form ENORMOUS arboreal colonies in tree canopies that aggressively defend the host trees from herbivores (similar to the famous bullhorn acacia ant Pseudomyrmex ferruginea — already in the Wild Files — though the Crematogaster relationships are typically less obligate). The species and genus are featured in essentially every modern textbook discussion of ant morphological diversity. The species is harmless to humans (no significant sting — Crematogaster have small stingers but rarely sting humans, and the sting is medically insignificant) and is a major beneficial generalist predator of small arthropods in eastern NA forests.