abstract: The sociobiology of Leptogenys ocellifera especially its predatory behavior and food recruitment was investigated. Leptogenys binghami and Leptogenys diminuta were observed comparatively. L. ocellifera: Colony size, nesting sites, and nest emigration. L. ocellifera lives in large colonies of several tens of thousands workers. It nests in existing soil cavities. The nesting site is changed in irregular intervals. According to our results the nest emigration is released by environmental factors.Trail system. There are several elaborated permanent routes leading from the nest into the surroundings. Those routes can be used continuously day and night over a period of several months. Guard ants are posting along the trails. Mainly in the evening, males were observed on the trails running back and forth. This behavior is interpreted as mating running". In the peripheral surroundings of the nest the routes may change within few hours or even minutes according to the food supply.Recruitment trails. The workers leave the nest singly or in groups. When an ant meets a prey animal it returns to the closest frequented trail rubbing its gaster tip on the ground while the sting is intermittendly extruded. The alarm secretion is released from the venom gland. It works as both orientation and recruiting signal and attracts new workers from the trail. No tactile signals are involved in food recruitment. The new workers in their turn intesify the alarm trail. Prey carrying workers lay trails to the nest which recruit further ants. Once the food source is exploited the alarm effect, even on strong trails, would decrease within half an hour. Recruitment trails which have been used over some time may become permanent routes. Along the permanent routes in addition to the recruiting substance an orientation component could be detected which lasts at least over 5 hrs. Its source is still unknownPredatory behavior. During foraging the workers frequently show digging behavior especially on places with fresh soil. Alarm secretion increases the digging activity. By this method L. ocellifera captures mainly animals which live in the soil, especially termites and earth worms. Other arthropods and snails are also predated. Larger prey objects are hunted and cut into pieces cooperatively. The pieces are transported into the nest by single workers. Killed termites are layed down near or on the trails by the foragers. Such depots are emptied by other workers. L. binghami and L. diminuta: L. binghami lives in natural earth cavities. It forages singly as a rule. Its main prey animals are termites. The trail secretion is mainly used during nest emigration. This is performed in a fast and well organized way. L. diminuta nests near the surface of the soil. It is a typical group prdator. The successful scouts lay recruiting trails while returning into the nest. The observed raids contained three to more than hundred workers led only sometimes by the scout. Prey objects (mainly larger arthropods) are hunted and retrieved cooperatively.
authors.affiliation: Fachbereich Biologie der Universität Frankfurt/M., Frankfurt/M., Deutschland.|Zoologisches Institut der Universität Heidelberg, Heidelberg, Deutschland.
authors.forename: U
authors.initials: U
authors.lastname: Maschwitz
authors.affiliation: Fachbereich Biologie der Universität Frankfurt/M., Frankfurt/M., Deutschland.|Zoologisches Institut der Universität Heidelberg, Heidelberg, Deutschland.
authors.forename: M
authors.initials: M
authors.lastname: Mühlenberg