Behavior of the cryptobiotic predaceous antEurhopalothrix heliscata, n. sp. (Hymenoptera: Formicidae: Basicerotini)

Abstract

1. Eurhopalothrix heliscata n. sp. is an Asiatic representative of the little known ant tribe Basicerotini and the first member of the group to be studied intensively. We report evidence that it preys on a variety of termites, but also takes at least some other kinds of insects. Overall, the social behavior is simple relative to that of many other myrmicine ants. 2. Prey are hunted and retrieved singly. But foraging workers are also able to recruit nestmates to the vicinity of groups of prey and as a result accelerate retrieval of termites to the brood chambers. A prolonged exploration of the surrounding area also ensues. 3. With the aid of chemical cues, workers are able to recognize material from the vicinity of their nest. 4. The workers are notably thigmotactic. They use their wedge-shaped heads, hard bodies, and short legs to press into tight spaces. They seize the appendages of termites with their short, sharp-toothed mandibles, clasping these body parts of the prey even more tightly with the aid of their projecting, heavily sclerotized labra. 5. E. heliscata tend to gather in large, broodless groups away from the main part of the colony. This bivouacing behavior, which effectively dispenses the foragers over a wider area, may improve the efficiency of the predation on termites. 6. The workers appear not to practice food exchange, worker oviposition, or alarmdefense behavior, nor do they recruit during colony emigration. 7. Prolonged fighting and dominance-subordinance relations among queens have been observed under laboratory conditions. 8. Other details of nesting behavior and social interactions are described (see,e.g., table I).