Orientation and recruitment behavior in the ponerine ant Pachycondyla tesserinoda (Emery): laying of individual-specific trails during tandem running

Summary Tandem leaders of Pachycondyla tesserinoda mark their way during nest moving. While scouting and foraging for food in an unknown area, chemical orientation is used as well. The origin of the trail substance could not be identified. Secretions of gastral exocrine glands did not induce trail following behavior. Nor do these secretions elicit tandem-following reactions; rather the latter is released by the general body surface odor. The trail substance and the substance used for marking the nest entrance are colony-specific. Moreover, individual tandem leaders recognize and show a preference for their own trails. This extraordinary effect is independent of the age of the trail. P. tesserinoda workers search individually for food and new nest sites. Targets which are important for the colony are directly shown to nestmates by tandem running. Due to this type of foraging and scouting individual-specific trails may be advantageous for this ant.     

Action and composition of the alarm pheromone of the bedbugCimex lectularius L.

The Science of Nature -     

Biodegradability assessment of several priority hazardous substances: choice, application and relevance regarding toxicity and bacterial activity

Nineteen compounds listed in the category of priority substances (PS) were selected for a biodegradation study using standardized tests. The compounds consist of pesticides, chlorinated solvents and volatile organic compounds (VOCs). In this paper, the choice of the most suitable method is discussed in relation to the physico-chemical properties of each substance. Zahn-Wellens, manometric respirometry and closed-bottle tests are alternatively used. Experimental results are presented and interpreted. Toxicity (Microtox) and bacterial viability (Bac-light) are also used as tools to investigate the influence of each substance on the microbial population (activated sludge). In addition, experimental values are compared with predictive data calculated according to quantitative structure activity relationships (QSARs) models. Biodeg Models were permitted to correctly estimate 17 substances; Survey Models and screening tests also revealed the same behavior for 16 target compounds.     

Ant-gardens of tropical Asian rainforests

Ant-garden (AG) associations are systems of epiphytic plants and arboricolous (i.e., tree-living) ants, in which the ants build fragile carton nests containing organic material. They collect and incorporate seeds or fruits of epiphytes that then germinate and grow on the nest [sensu Corbara et al. (1999) 38:73–89]. The plant roots stabilize the nest carton. AGs have been well-known in the neotropics for more than 100 years. In contrast, reports on similar associations in the paleotropics are scarce so far. After discovering a first common AG system on giant bamboo [Kaufmann et al. (2001) 48:125–133], we started a large-scale survey for AGs in Peninsular Malaysia, Borneo, Java, and southern Thailand. A great variety of AG systems (altogether including 18 ant species and 51 plant species) was discovered and is described in the present paper. The high number of species participating in AG associations was reflected by a great variability in the specific appearances of the nest gardens. Frequently, further groups of organisms (e.g., hemipteran trophobionts, fungi) were also involved. Preference patterns of particular ant and epiphyte species for each other and for particular phorophytes (carrier trees) were detected. We integrate domatia-producing, so-called ant-house epiphytes in our study and compare their phases of establishment, as well as other characteristics, to “classical” AGs, coming to the conclusion that they should be regarded only as a special type of AG epiphyte and not as a separate ecological category.Electronic Supplementary Materials  Supplementary material is available for this article at     

Communal peeing: a new mode of flood control in ants

 The behavioral response of the obligate bamboo-nesting ant Cataulacus muticus to nest flooding was studied in a perhumid tropical rainforest in Malaysia and in the laboratory. The hollow internodes of giant bamboo, in which C. muticus exclusively nests, are prone to flooding by heavy rains. The ants showed a two-graded response to flooding. During heavy rain workers block the nest entrances with their heads to reduce water influx. However, rainwater may still intrude into the nest chamber. The ants respond by drinking the water, leaving the nest and excreting water droplets on the outer stem surface. This cooperative 'peeing' behavior is a new survival mechanism adaptive to the ants' nesting ecology. Laboratory experiments conducted with two other Cataulacus species, C. catuvolcus colonizing small dead twigs and C. horridus inhabiting rotten wood, did not reveal any form of water-bailing behavior. Received: 3 August 2000 / Accepted in revised form: 6 November 2000