Geographical variation in sexual behavior and body traits in a sex role reversed wolf spider

Mating partners need to recognize, assess each other, and exchange information through behavioral events that occur before, during, and after mating. Sexual signals, as well as life history traits, are influenced by selective pressures and environmental factors that can vary across distant geographical areas. Allocosa senex is a sand-dwelling wolf spider which constructs burrows along the sandy coasts of Argentina, Brazil, and Uruguay. Females are the mobile sex that searches for males and initiates courtship. They prefer males which construct longer burrows, and males prefer virgin females in good body condition. The objective of this study was to compare sexual behavior patterns, as well as body characteristics and burrow dimensions, between two geographically distant locations of A. senex, one in Uruguay (Uruguayan location) and the other from central Argentina (Argentinean location). We found differences in the number of male abdominal vibrations, male and female touches during mating, and number of erections of male leg spines, which all were higher in matings of Argentinean pairs. On the other hand, male body mass and female body condition were higher in Uruguayan individuals. The wide distribution of A. senex could be determining variations in the biotic and abiotic features that affect the species, generating differences in the strength of selective forces acting on individuals from the two studied locations.     

Moroccan actinobacteria with promising activity against toxic cyanobacteria Microcystis aeruginosa

Environmental Science and Pollution Research - In recent decades, harmful cyanobacterial blooms (HCBs) have become a severe hazard for human health mainly in drinking water resources and are...     

Evaluation of the capacity of the cyanobacterium Microcystis novacekii to remove atrazine from a culture medium

The bioaccumulation of atrazine and its toxicity were evaluated for the cyanobacterium Microcystis novacekii. Cyanobacterial cultures were grown in WC culture medium with atrazine at 50, 250 and 500 μg L^?1. After 96 hours of exposure, 27.2% of the atrazine had been removed from the culture supernatant. Spontaneous degradation was found to be insignificant (< 9% at 500 μg L^?1), indicating a high efficiency for the bioaccumulation of atrazine by M. novacekii. There were no atrazine metabolites detected in the culture medium at any of the doses studied. The acute toxicity (EC₅₀) of atrazine to the cyanobacterium was 4.2 mg L^?1 at 96 hours demonstrating the potential for M. novacekii to tolerate high concentrations of this herbicide in fresh water environments. The ability of M. novacekii to remove atrazine combined with its tolerance of the pesticide toxicity showed in this study makes it a potential biological resource for the restoration of contaminated surface waters. These findings support continued studies of the role of M. novacekii in the bioremediation of fresh water environments polluted by atrazine.     

Bike Networking in Rio: The challenges for non-motorised transport in an automobile-dominated government culture

Rio de Janeiro has developed, since 1992, an 84 km cycling network, more as the outcome of green and NGO lobbying than of clear cut and continuous government choices. The city transport policies are widely dominated by car and bus oriented priorities with insufficient investment in rail, ferryboat and other mass transport options. Bicycle use is potentially part of a new policy aimed at reducing automobile dependence and its social and environmental consequences. The Rio experience was influenced by the Dutch example, especially the Amsterdam achievements. The process of building this cycling infrastructure is also a political and cultural one, sometimes encountering tough resistance from some sectors of the city government and the public, hostile to an investment they consider futile. However, opinion polls conducted in Rio have shown impressive support for bike networking. The main conditions for success are: good integration, maintenance and security; appropriate support infrastructure; and continuity with regular investments and upgrading.     

Analysis of Spatial and Temporal Evolution of Vegetation Cover in the Spanish Central Pyrenees: Role of Human Management

A vegetation cover increase has been identified at global scales using satellite images and vegetation indices. This fact is usually explained by global climatic change processes such as CO₂ and temperature increases. Nevertheless, although these causes can be important, the role of socioeconomic transformations must be considered in some places, since in several areas of Northern Hemisphere an important change in management practices has been detected. Rural depopulation and land abandonment have reactivated the natural vegetation regeneration processes. This work analyses the vegetation evolution in the central Spanish Pyrenees from 1982 to 2000. The analysis has been done by using calibrated-NDVI temporal series from NOAA-AVHRR images. A positive and significant trend in NDVI data has been identified from 1982 to 2000 coinciding with a temperature increase in the study area. However, the spatial differences in magnitude and the sign of NDVI trends are significant. The role of land management changes in the 20th century is considered as a hypothesis to explain the spatial differences in NDVI trends. The role of land-cover and human land-uses on this process has been analyzed. The highest increment of NDVI is detected in lands affected by abandonment and human extensification. The importance of management changes in vegetation growth is discussed, and we indicate that although climate has great importance in vegetal evolution, land-management changes can not be neglected in our study area.     

Populations, longevity, mortality and fecundity of Chrysoperla carnea (Neuroptera, Chrysopidae) from olive-orchards with different agricultural management systems

The influence that different styles of olive-orchard management (conventional, integrated, and organic) exert on the predator Chrysoperla carnea has been studied to strengthen this insect’s role in the integrated management against pests. For this, the adult chrysopid populations were determined by McPhail traps, and laboratory examinations were made of certain biological characteristics of the first generation of adults captured in each of the olive orchards studied. The chrysopid populations increasing significantly during some months in the integrated and organic olive orchard. The most abundant species in all the zones was C. carnea, representing 95% of all captures in the conventional olive orchard. It was found that the larvae from the integrated olive orchard took longer to develop, while the pupae from the organic orchard evolved most rapidly to adulthood. The highest mortality rate was for larvae in the conventional olive orchard. The fecundity of the females from the organic orchards was significantly greater, presumably due to their greater longevity and shorter pre-oviposition period. These results can be used to improve conservation strategies and to increase C. carnea populations and their predatory activity.     

Synchrotron X-ray fluorescence and trace metals in the cementum rings of human teeth

Synchrotron micro X-ray fluorescence has been used to study differences in the trace element concentration between the dentine and cementum rings of human teeth. The results show that metals such as zinc are concentrated in the cementum rings. This suggests that if the rings are deposited annually a temporal record of metal exposure may be extracted from this material.     

Ethanol From Corn: Clean Renewable Fuel for the Future,or Drain on Our Resources and Pockets?

It is shown here that one burns 1 gallon of gasoline equivalent in fossil fuels to produce 1 gallon of gasoline equivalent as ethanol from corn. When this corn ethanol is burned as a gasoline additive or fuel, its use amounts to burning the same amount of fuel twice to drive a car once. Therefore, the fuel efficiency of those cars that burn corn ethanol is halved. The widespread use of corn ethanol will cause manifold damage to air, surface water, soil and aquifers. The overall energy balance of corn conversion to ethanol demonstrates that 65% of the input energy is lost during the conversion. Carbon dioxide sequestration by corn is nullified when corn ethanol is burned, and there will be additional carbon dioxide, nitrous oxides, and sulfur oxide emissions from the fossil fuels used to produce the ethanol. Students in the Spring 2003 CE24 Freshman Seminar offered at U.C. Berkeley by the Civil and Environmental Engineering Department Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.