C. elegans odour discrimination requires asymmetric diversity in olfactory neurons

Caenorhabditis elegans senses at least five attractive odours with a single pair of olfactory neurons, AWC, but can distinguish among these odours in behavioural assays. The two AWC neurons are structurally and functionally similar, but the G-protein-coupled receptor STR-2 is randomly expressed in either the left or the right AWC neuron, never in both. Here we describe the isolation of a mutant, ky542, with specific defects in odour discrimination and odour chemotaxis. ky542 is an allele of nsy-1, a neuronal symmetry, or Nsy, mutant in which STR-2 is expressed in both AWC neurons. Other Nsy mutants exhibit discrimination and olfactory defects like those of nsy-1 mutants. Laser ablation of the AWC neuron that does not express STR-2 (AWCOFF) recapitulates the behavioural phenotype of Nsy mutants, whereas laser ablation of the STR-2-expressing AWC neuron (AWCON) causes different chemotaxis defects. We propose that odour discrimination can be achieved by segregating the detection of different odours into distinct olfactory neurons or into unique combinations of olfactory neurons.     

Resident Utah deer hunters' preferences for management options

A total of 3291 resident deer hunters returned questionnaires distributed at checking stations in fall 1989 and 1990 providing opinions and management data concerning the Utah rifle hunt. Hunters reported hunter crowding and too few big bucks as critical reasons for possibly choosing to quit deer hunting in Utah. Indeed, hunter age structure and measured satisfaction suggested a negative future trend in hunter participation. Results suggested the adoption of several hunter-preferred management options would increase satisfaction, motivation, and success.     

Effectiveness of the global protected area network in representing species diversity

The Fifth World Parks Congress in Durban, South Africa, announced in September 2003 that the global network of protected areas now covers 11.5% of the planet's land surface. This surpasses the 10% target proposed a decade earlier, at the Caracas Congress, for 9 out of 14 major terrestrial biomes. Such uniform targets based on percentage of area have become deeply embedded into national and international conservation planning. Although politically expedient, the scientific basis and conservation value of these targets have been questioned. In practice, however, little is known of how to set appropriate targets, or of the extent to which the current global protected area network fulfils its goal of protecting biodiversity. Here, we combine five global data sets on the distribution of species and protected areas to provide the first global gap analysis assessing the effectiveness of protected areas in representing species diversity. We show that the global network is far from complete, and demonstrate the inadequacy of uniform--that is, 'one size fits all'--conservation targets.