Proatta butteli

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia. Oriental Region: Thailand, Vietnam.

Biology
Moffett (1987) - Proatta butteli workers scavenge for invertebrate remains and prey on live arthropods. The ants also collect bits of fresh or dried vegetations, wood, and other plant material and recruit to piles of sesame seeds provided near nest entrances. Apparently none of these plant materials are eaten, however, although they are added to the debris the ants let accumulate inside the nest.

Colonies of Proatta butteli are polygynous, with numerous queens present. There is no evidence for aggression between queens or differential treatment of queens by workers. Also, there is no sign of intraspecific aggression: the ants readily acceptted workers transplanted from distant sites.

Workers search for food solitarily, foraging only a short distance (invariably less than a meter) from each nest entrance. Within the limited foraging area worker density tends to be high, and clumps of as many as 5O foragers are sometimes present. This foraging pattern allows for rapid exploitation of discovered food. Recruitment occurs along odor trails formed from a pheromone originating in the poison gland.

In addition to small prey and scavenged arthropod corpses, the ants capture prey larger than themselves. Such prey are taken by an inchoate form of group predation. The first worker to encounter the prey attempts to restrain it. Because of the high forager density, additional workers soon arrive seemingly by chance and aid in pinning the prey in place. Unlike attine ants, Proatta butteli does not feed on fungi.

Although workers vary little in head width (0.51 to 0.70 mm), they show a modest division of labor by size, with smaller individuals being relatively numerous in the brood area.

Nesting Biology
Most nests are near tree bases. Colonies infiltrate rotten roots, abandoned termite nests, and other cavities near the surface, forming within them a labyrinth of chambers and galleries. The ants apparently make use of available spaces, with little additional excavation. The chamber surfaces are lined with detritus such as woody frass and prey' remains. Dealate queens are numerous, with roughly one queen for every 100-500 workers throughout the nest. Nest entrances are scattered on the ground above the chambers, and are unornamented except for strewn debris. The primary study colony is one of the largest I have seen, probably containing several thousand ants, and possibly 10,000 or more. The nest site has been occupied for at least 3 years.

Nomenclature

 *  butteli. Proatta butteli Forel, 1912m: 769 (w.m.) INDONESIA (Sumatra). Crawley, 1924: 401 (q.); Wheeler, G.C. & Wheeler, J. 1986b: 447 (l.). [Also described as new by Forel, 1913k: 86.] See also: Moffett, 1987: 444.

Queen
Moffett (1987) - Total length about 6 mm, with little size variation. Head width of three Singaporean gynes 1.05-1.06 mm; head length 1.08-1.10 mm; cephalic index 96-98. Head similar to that of worker, but roughly triangular in full face view; eyes oval, maximum diameter about 20% of head length; ocelli prominent; mandibles and antennae as in worker. Trunk massive, with full complement of flight sclerites, and only about 25% longer than high; very similar in shape to that of Atta gynes. Metanotum with a single blunt spine medad, as in male. Petiole and postpetiole as in worker. Gaster heavily sclerotized, massive, of a length slightly greater than that of ali trunk. Head and alitrunk areolate-rugose (with alveolate microsculpturing) as in workers but more strongly impressed.