Dispersal and distribution in Leopoldinia (Palmae)

The Amazon palm genus Leopoldinia exemplifies the transition from a terrestrial to an amphibious life-style, accompanied by a switch from synzoochorous dispersal to hydrochory. Leopoldinia piassaba produces heavy fruits with a fleshy, sweet mesocarp and is presumed to be dispersed by terrestrial animals. This species enters aquatic habitats only so far as these are submersed for a short while. The other two species, L. major and L. pulchra , resist long-lasting submersion and have much smaller, buoyant fruits, which are dispersed by water and are produced in proportionately larger guantities. They are eaten and mostly destroyed, but occasionally probably also dispersed by fish. L. pulchra , the species with the smallest fruits, has acquired the widest geographical distribution.     

Dispersal in sub-Saharan baboons.

In most mammalian species, males tend to leave their natal group and disperse farther than females, while females tend to be philopatric. Primates generally follow this rule, although long-term studies of a variety of species are revealing an increasing number of exceptions. This paper reviews dispersal patterns in 3 subspecies of savanna baboons (Papio cynocephalus cynocephalus, P. cynocephalus anubis, P. cynocephalus ursinus) which exhibit very similar patterns of social organization. Males usually disperse from the natal group at 8-10 years of age. Female dispersal is rare but well documented. Inbreeding avoidance as well as enhanced mating opportunities are suggested as ultimate causes of dispersal. Several proximate factors implicated in the timing of dispersal events are also reviewed.     

Dispersal of Acacia cyclops by birds

Summary In South Africa seedlings of the exotic Acacia cyclops grow in clumps. The seedlings occur beneath tall elements, or in bush clumps, of the surrounding indigenous vegetation. The tall shrubs are used as perches by birds, and the pattern of seedling distribution is a result of dispersal of seeds by birds. Germination of A. cyclops seeds was enhanced as a result of passage through the gut of a bird, or by artificial treatments simulating actions taking place in the gut of a bird. We examine properties of the seed, and the funicle which is attractive to birds, in relation to aspects of the life history of A. cyclops and the species' success as an invasive plant in South Africa.     

Prof. Dr. Habil. Klaus Naumann 70 Jahre

In den Jahren 1990 und 1991 wurden Untersuchungen zum Einfluß des Fungizids Furesan (Flusilazol + Pyrazophos) auf räuberische Käfer in Wintergerstefeldern bei Halles/S. mittels Bodenfallen auf Großparzellen durchgeführt. Die Applikation von Furesan fand im Jahre 1990 zum Schossen (DC 37/40) und zum Beginn des Ährenschiebens (DC 49/52), 1991 nur zum Schossen der Wintergerste, aber im Vergleich zu Desmel (Propiconazol) statt. Furesan rief im Jahre 1990 zum Schossen der Wintergerste nur in der ersten Woche nach Behandlung schwache Nebenwirkungen bei Laufkäfern (Carabidae) und Kurzflüglern (Staphylinidae) hervor. Die Applikation zum Ährenschieben beeinflußte die Laufkäfer nicht und die Kurzflügler nur schwach. Im Jahre 1991 fielen die Nebenwirkungen zum Schossen noch geringer als 1990 aus. Nur bei der häufigsten Kurzflüglerart Tachyporus hypnorum (L.) wurden im Jahre 1990 mittlere, 1991 zeitweise sogar starke Minderungen durch die Fungizide hervorgerufen.     

Dispersal distance is influenced by parental and grand-parental density

Non-genetic transmission of information across generations, so-called parental effects, can have significant impacts on offspring morphology, physiology, behaviour and life-history traits. In previous experimental work using the two-spotted spider mite Tetranychus urticae Koch, we demonstrated that dispersal distances increase with local density and levels of genetic relatedness. We here show that manipulation of parental and grand-parental density has a significant effect on offspring dispersal distance, of the same order of magnitude as manipulation of offspring density. We demonstrate that offspring exposed to the same density disperse further if they were born to parents exposed to higher density compared with parents exposed to low density. Offspring dispersal distance also increases when grand-parents were exposed to higher density, except for offspring exposed to low densities, which disperse at shorter distances whatever the grand-parental density. We also show that offspring from mothers exposed to higher densities were overall larger, which suggests that parents in high densities invest more in individual offspring, enabling them to disperse further. We propose that our findings should be included in models investigating the spread rate of invasive species or when predicting the success of conservation measures of species attempting to track changing climates.     

Intercontinental Dispersal of Bacteria and Archaea by Transpacific Winds

Microorganisms are abundant in the upper atmosphere, particularly downwind of arid regions, where winds can mobilize large amounts of topsoil and dust. However, the challenge of collecting samples from the upper atmosphere and reliance upon culture-based characterization methods have prevented a comprehensive understanding of globally dispersed airborne microbes. In spring 2011 at the Mt. Bachelor Observatory in North America (2.8 km above sea level), we captured enough microbial biomass in two transpacific air plumes to permit a microarray analysis using 16S rRNA genes. Thousands of distinct bacterial taxa spanning a wide range of phyla and surface environments were detected before, during, and after each Asian long-range transport event. Interestingly, the transpacific plumes delivered higher concentrations of taxa already in the background air (particularly Proteobacteria, Actinobacteria, and Firmicutes). While some bacterial families and a few marine archaea appeared for the first and only time during the plumes, the microbial community compositions were similar, despite the unique transport histories of the air masses. It seems plausible, when coupled with atmospheric modeling and chemical analysis, that microbial biogeography can be used to pinpoint the source of intercontinental dust plumes. Given the degree of richness measured in our study, the overall contribution of Asian aerosols to microbial species in North American air warrants additional investigation.