Biochemical evidence accumulates across neurons to drive a network-level eruption

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Modelling biological invasions over homogeneous and inhomogeneous landscapes using level set methods

The establishment, spread and subsequent degradation of existing environments by invasive species is a worldwide problem affecting native and agricultural ecosystems. The phenomenal cost to governments as a result of research and eradication or control drives the need to understand invasion characteristics. In this paper we develop a method for modelling the boundary of an invasion over time with model inputs being the initial distribution of the invasion and the speed at which the invasion front moves over time. This speed function can depend on the topography of the ground cover and we consider examples of homogeneous and inhomogeneous spread. The possibility of a long-distance dispersal event occurring is also considered. In particular, examples of the spread of emergent weeds and weeds which favour creeks and river beds in New Zealand are presented.     

Taylor's law and body size in exploited marine ecosystems

Taylor's law (TL), which states that variance in population density is related to mean density via a power law, and density‐mass allometry, which states that mean density is related to body mass via a power law, are two of the most widely observed patterns in ecology. Combining these two laws predicts that the variance in density is related to body mass via a power law (variance‐mass allometry). Marine size spectra are known to exhibit density‐mass allometry, but variance‐mass allometry has not been investigated. We show that variance and body mass in unexploited size spectrum models are related by a power law, and that this leads to TL with an exponent slightly <2. These simulated relationships are disrupted less by balanced harvesting, in which fishing effort is spread across a wide range of body sizes, than by size‐at‐entry fishing, in which only fish above a certain size may legally be caught.     

<Emphasis Type="Italic">PLP1</Emphasis> Gene Variation Modulates Leftward and Rightward Functional Hemispheric Asymmetries

Molecular neurobiological factors determining corpus callosum physiology and anatomy have been suggested to be one of the major factors determining functional hemispheric asymmetries. Recently, it was shown that allelic variations in two myelin-related genes, the proteolipid protein 1 gene PLP1 and the contactin 1 gene CNTN1, are associated with differences in interhemispheric integration. Here, we investigated whether three single nucleotide polymorphisms that were associated with interhemispheric integration via the corpus callosum in a previous study also are relevant for functional hemispheric asymmetries. To this end, we tested more than 900 healthy adults with the forced attention dichotic listening task, a paradigm to assess language lateralization and its modulation by cognitive control processes. Moreover, we used the line bisection task, a paradigm to assess functional hemispheric asymmetries in spatial attention. We found that a polymorphism in PLP1, but not CNTN1, was associated with performance differences in both tasks. Both functional hemispheric asymmetries and their modulation by cognitive control processes were affected. These findings suggest that both left and right hemisphere dominant cognitive functions can be modulated by allelic variation in genes affecting corpus callosum structure. Moreover, higher order cognitive processes may be relevant parameters when investigating the molecular basis of hemispheric asymmetries.     

Smell the change: On the potential of gas‐chromatographic ion mobility spectrometry in ecosystem monitoring

Plant volatile organic compounds (pVOCs) are being recognized as an important factor in plant–environment interactions. Both the type and amount of the emissions appear to be heavily affected by climate change. A range of studies therefore has been directed toward understanding pVOC emissions, mostly under laboratory conditions (branch/leaf enclosure). However, there is a lack of rapid, sensitive, and selective analytical methods, and therefore, only little is known about VOC emissions under natural, outdoor conditions. An increased sensitivity and the identification of taxon‐specific patterns could turn VOC analysis into a powerful tool for the monitoring of atmospheric chemistry, ecosystems, and biodiversity, with far‐reaching relevance to the impact of climate change on pVOCs and vice versa. This study for the first time investigates the potential of ion mobility spectrometry coupled to gas‐chromatographic preseparation (GC‐IMS) to dramatically increase sensitivity and selectivity for continuous monitoring of pVOCs and to discriminate contributing plant taxa and their phenology. Leaf volatiles were analyzed for nine different common herbaceous plants from Germany. Each plant turned out to have a characteristic metabolite pattern. pVOC patterns in the field would thus reflect the composition of the vegetation, but also phenology (with herbaceous and deciduous plants contributing according to season). The technique investigated here simultaneously enables the identification and quantification of substances characteristic for environmental pollution such as industrial and traffic emissions or pesticides. GC‐IMS thus has an enormous potential to provide a broad range of data on ecosystem function. This approach with near‐continues measurements in the real plant communities could provide crucial insights on pVOC‐level emissions and their relation to climate and phenology and thus provide a sound basis for modeling climate change scenarios including pVOC emissions.     

Antennale Rezeptoren für Queen Substance und Sterzelduft bei der Honigbiene

Zusammenfassung Auf den Antennen aller drei Kasten von Apis mellifica konnten elektrophysiologisch 2 Typen von Riechzellen identifiziert werden, die auf Pheromone der Biene antworten. Der eine Typ ist auf Queen substance (9-Oxo-trans-2-decensäure), der andere auf den Sterzelduft der Arbeiterin spezialisiert. Beide Zelltypen werden bei Ableitungen von Porenplatten gefunden.

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Antennal receptors for queen substance and scent gland odour in honeybees

Summary Electrophysiologically, we could identify two types of olfactory receptor cells, which respond to pheromones of the honeybee. These cells are associated with the poreplates on the antennae of all three castes of Apis mellifica. One of the cell types is specialized for the queen substance (9-oxo-trans-2-decenoic acid) while the other responds to the scent of the Nasanov gland.