Dominions and desert clickers (Orthoptera:Acrididae): influences of resources and male signaling on female settlement patterns

Summary Previous field work on the grasshopper Ligurotettix coquilletti revealed that females were not evenly distributed among male mating territories, Larrea tridentata (creosote) bushes, but were clustered at particular locations. These sites generally harbored several signaling males simultaneously and also possessed foliage preferred by the insects as a food source, this preference being based on the relative concentrations of various extra-foliar compounds. The clustering of females, therefore, could result from a preference for specific bushes because of the resources (i.e., food) available there and/or an orientation to groups of males per se. Here, we present the results of 3 field experiments in which we controlled the spatial distribution and intensity of male signals using a computer-operated system of loudspeakers and monitored the movement of individually marked females released in the study area. When male song was identical at high and low quality territories (all having single loudspeakers), females still aggregated at the high quality sites, indicating that variability in host plant quality alone may be sufficient to promote a skewed distribution of females. Among high quality territories, females did not discriminate between sites with one versus three loudspeakers (all broadcasting the same signal), but displayed a strong preference for sites (all having single loudspeakers) with a high intensity signal over a low intensity one. Field measurements showed that the songs of grouped males were more intense than those of lone males, implying that the signaling of grouped males may have enhanced the settlement of females at the bushes harboring male groups above and beyond that influenced by territory quality alone. We conclude that female attraction to host plants is influenced primarily by male signaling, whereas their subsequent retention is more dependent on territory quality. An experiment on male settlement failed to show an aggregative tendency, suggesting that male groups form through the passive accumulation of individuals at high quality sites.     

Song as an attractant for male and female European starlings,and the influence of song complexity on their response

Summary We tested the hypothesis that song attracts females and repels males in the European starling. We broadcast recorded song from speakers attached to nestboxes, while paired boxes with silent speakers served as controls. As predicted, females were attracted to the song boxes. Contrary to prediction, males were also attracted to the `song' boxes. Singing by male starlings may be costly because it attracts competitors for limited nesting sites, but the cost cannot be avoided due to the need to attract a mate. In a second experiment simple song (composed of 20 different phrase types) and complex song (40 phrase types) were played simultaneously. More males were captured at boxes where simple song was played. Song complexity may function as an indicator of male quality and be used by male starlings to assess potential competitors.     

Soil sampling and analysis for volatile organic compounds

Concerns over data quality have raised many questions related to sampling soils for volatile organic compounds (VOCs). This paper was prepared in response to some of these questions and concerns expressed by Remedial Project Managers (RPMs) and On-Scene Coordinators (OSCs). The following questions are frequently asked:

1. Is there a specific device suggested for sampling soils for VOCs?
2. Are there significant losses of VOCs when transferring a soil sample from a sampling device (e.g., split spoon) into the sample container?
3. What is the best method for getting the sample from the split spoon (or other device) into the sample container?
4. Are there smaller devices such as subcore samplers available for collecting aliquots from the larger core and efficiently transferring the sample into the sample container?
5. Are certain containers better than others for shipping and storing soil samples for VOC analysis?
6. Are there any reliable preservation procedures for reducing VOC losses from soil samples and for extending holding times?

Guidance is provided for selecting the most effective sampling device for collecting samples from soil matrices. The techniques for sample collection, sample handling, containerizing, shipment, and storage described in this paper reduce VOC losses and generally provide more representative samples for volatile organic analyses (VOA) than techniques in current use. For a discussion on the proper use of sampling equipment the reader should refer to other sources (Acker, 1974; U.S. EPA, 1983; U.S. EPA, 1986a). Soil, as referred to in this report, encompasses the mass (surface and subsurface) of unconsolidated mantle of weathered rock and loose material lying above solid rock. Further, a distinction must be made as to what fraction of the unconsolidated material is soil and what fraction is not. The soil component here is defined as all mineral and naturally occurring organic material that is 2 mm or less in size. This is the size normally used to differentiate between soils (consisting of sands, silts, and clays) and gravels. Although numerous sampling situations may be encountered, this paper focuses on three broad categories of sites that might be sampled for VOCs:

1. Open test pit or trench.
2. Surface soils (<5 ft in depth).
3. Subsurface soils (>5 ft in depth).

     

Relevance of radiation compensation litigation to compensation for toxic exposures

Several recent court decisions add to the growing body of law concerning the responsibility of Government in radiation matters and the quantum of proof needed to show causation between radiation exposures and certain types of cancer and leukemia. The courts have also been addressing a wide range of compensation claims for exposures to toxic chemicals with demonstration of causation being a particularly difficult task. Meanwhile, the Congress has been attempting to legislate a far reaching administrative and judicial framework for compensating toxic victims, including an easing of burden-of-proof requirements for demonstrating causation and a broadening of the basis for admissibility of scientific evidence. Drawing parallels between radiation and toxic exposure problems can be both instructive and misleading. Some of the technical issues are quite similar, including the importance of person-specific exposure estimates and of epidemiological studies. However, the uncertainties associated with toxic exposures are usually far greater, and the scientific data base for relating exposures and effects is much more uncertain.     

Problems of correlation of global and local monitoring of air pollution

1. The Air Polluttion Monitoring System has got a significant development of late, which is in direct relation with a considerable extention and improvement of the observation network in cities and industrial areas, with creation of a new network for assessing regional and global background of the atmosphere pollution, as well as with the wide involvement of meteorologists to monitoring organization.
2. While developing a new global monitoring system, it is necessary to take into account its relationship with the local monitoring within the region of air pollution sources, i.e. at the \lsimpact\rs level. The need in such an account is dictated first of all by the physics of pollutant spreading that states: changes in air pollution over large territories must be in a certain agreement with greater changes in the vicinity of emission sources. Methods applied in the global and local monitoring have also a number of common peculiarities. White organizing regional network for observations of the background pollution of the atmosphere twin stations (one of the pair of stations located outside the city boundaries in a small community, and the other, in the nearest city with the population of 200–400 thousand inhabitants) were established in the U.S.S.R. and in a number of socialist countries in Europe.
3. Implementation of the twin-station principles in the U.S.S.R. has contributed to data interpretation and representativity assessment as well as to correction of the station location. Observation results from the Soviet background stations and those abroad have been compared by now according to a number of indices.
4. The correlation of monitoring systems of various scales tells positively both on mutual improvement and completion of observational methods. The methods of obtaining integral characteristics of air pollution were used for the global monitoring, in particular spectral actinometric observations and chemical analysis of the precipitation composition. Now they find still wider employment. Thus methods of spectral actinometric measurements and data processing were used to estimate the degree of aerosol pollution of a number of industrial centres. The theory of solar radiation spreading and aerosol contents determination in urban atmosphere has also been developed. It is a generalization of an earlier developed theory, used to estimate global atmosphere pollution basing on actinometric data. The organization of precipitation collection and analysis on a network of stations around Leningrad and in Donbass area enables us to compare the admixture content in precipitations falling in industrial and agricultural areas.
5. A considerable increase of possibilities to measure microconcentrations of sulphur dioxide, nitrogen oxides and of a number of other pollutants is connected with the use of solid solvents for sampling. Their use will allow to avoid establishment of special laboratories at background stations and only send samples by post for their analysis in centralized laboratories.

They will also allow to considerably increase precision and accuracy of measurements. The international comparisons of methods of air pollution measurements on the background level allow to judge about the effiency of these methods.     

Fractionation of butyltin species during sample extraction and preparation for analysis

Solvent extraction and evaporative concentration steps are often used in procedures for the measurement of butyltins in environmental samples. As part of a larger study utilizing radiolabeled butyltins, the loss and fractionation of butyltins during sample preparation was investigated. TBT, DBT, and MBT were extracted from acidified seawater by hexane with efficiencies of about 95–99, 50–60 and 11% respectively. In addition, losses of about 70% of DBT were found during evaporative concentration of hexane. A variety of sediment extraction procedures were tested and none were found to be highly efficient for total butyltin extraction.