Assessment of Metal Contamination in Doñana National Park (Spain) using Crayfish (Procamburus Clarkii)

Water quality assessment in the Aznalcollar area was attempted using multivariate methods based on heavy metal concentrations in red swamp crayfish (Procamburus clarkii). Trace levels of four heavy metals, copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), were detected in crayfish from eleven different stations. Principal component analysis (PCA) highlighted a gradient of contamination between the sampling stations. Cluster analysis (CA) distinguished three groups of stations. Discriminant analysis also differentiated three groups. The group centroids of the first discriminant function were used to devise an index that varies according to the source of the crayfish. These standardized values are proposed for use as a water quality index. The ability of this index to successfully predict environmental quality was proved with random samples.     

Environmental and sustainability indicators and the concept of situational indicators. A systems approach

Through a systems approach indicators are shown to have the nature of variables, adopting different values or states, while other associated terms allude to special meanings assigned to specific values of the indicators. Practical implications are discussed. The concept of situational indicators of sustainability is introduced, representing a non-numerical function of both “pressures” or “driving forces” and “state” variables. A cost-effective multi-tiered approach to situational indicators is proposed. The concept of situational indicators is shown to be a particular case of indicators of systems behavior. A general systems formulation of the problem of sustainability highlights the importance of indicators of systems behavior and the central role of models in their definition.     

Non-random nectar unloading interactions between foragers and their receivers in the honeybee hive

Nectar acquisition in the honeybee Apis mellifera is a partitioned task in which foragers gather nectar and bring it to the hive, where nest mates unload via trophallaxis (i.e. mouth-to-mouth transfer) the collected food for further storage. Because forager mates exploit different feeding places simultaneously, this study addresses the question of whether nectar unloading interactions between foragers and hive-bees are established randomly, as it is commonly assumed. Two groups of foragers were trained to exploit a different scented food source for 5 days. We recorded their trophallaxes with hive-mates, marking the latter ones according to the forager group they were unloading. We found non-random probabilities for the occurrence of trophallaxes between experimental foragers and hive-bees, instead, we found that trophallactic interactions were more likely to involve groups of individuals which had formerly interacted orally. We propose that olfactory cues present in the transferred nectar promoted the observed bias, and we discuss this bias in the context of the organization of nectar acquisition: a partitioned task carried out in a decentralized insect society.     

Synthesis and structure-activity relationship of diene modified analogs of<Emphasis Type="Italic"> Matsucoccus</Emphasis> sex pheromones

The biological activity of the Matsucoccus spp. sex pheromones and diene modified analogs has been tested in forests of Israel and Portugal in order to explore the structure-activity relationship of the pine bast scale pheromone/kairomone system. The response of the adult predatory bugs, Elatophilus hebraicus and E. crassicornis and of the brown lacewing, Hemerobius stigma is more selective than that of the conspecific Matsucoccus males. The removal of the terminal methyl group from the diene terminus of both pheromones 1 and 2 eliminates all kairomonal activity but retains moderate pheromonal activity. Addition of a methyl group to the diene terminus of pheromones 1 and 2 sustains full pheromonal and kairomonal activities of the Elatophilus spp. but eliminates entirely the kairomonal activity of H. stigma. Subtle designed alterations in the structure of the diene group, typical of all Matsucoccus pheromones, change the mode of the kairomonal activity markedly.