Abstract Microtox and Ames bioassays were employed to assess acute toxicity and mutagenicity of water soluble components of class–fractionated oils extracted from one creosote–and four petroleum–contaminated soils. Microtox results revealed that potential acute toxicity resides mainly in the polar class fractions at three sites and indicated potential synergistic and antagonistic effects between compounds in the total extracts at two sites. Ames Salmonella/microsome testing indicated that the polyaromatic fractions at two sites exhibit weak mutagenicity with enzymatic activation, while the polar fractions at two sites are weakly mutagenic without enzyme activation. Further chemical characterization of the polar and polyaromatic fractions is required to fully assess the potential of health and ecological risks at the creosote–and petroleum–contaminated sites exhibiting these toxic responses. 相似文献
Sexual selection can act through female choice and male–male competition. Although both processes can act simultaneously,
they are typically studied independently. Here, we adopt a more integrated approach to studying sexual selection by incorporating
measures of both processes using the western rainbowfish Melanotaenia australis, a freshwater fish endemic to northwestern Australia. We assessed male–male competition and female choice separately while
measuring the performance of individual males under both processes and used paternity analyses to estimate male reproductive
success. We then related the performance of males during each of these stages to their phenotype, which was described using
linear measures of size and color pattern traits, and spectrographic measures of the reflectance of color patches. We found
that female choice favored relatively large males and that these preferences were consistent within individual females and
repeatable between different females. Larger males were also more dominant in the competition trials and sired the majority
of offspring produced when females spawned. There was little evidence to suggest that sexual selection acted on male color
patterns either via female choice or male contest competition or during subsequent post-mating episodes of sexual selection.
We conclude, therefore, that male–male competition and female choice act concordantly to favor relatively large males and
that these patterns of mating success are reflected during post-mating episodes of sexual selection. 相似文献
Facultative traits that have evolved under sexual selection, such as the acoustic ornaments present in the advertisement signals
of male túngara frogs (Physalaemus pustulosus), offer a unique opportunity to examine selection for trait exaggeration with a focus on individual differences amongst signalers.
By contrast, many studies of mate choice use experimental designs that obscure the inter-individual variation amongst signalers
available for selection to act on—through the use of “typical” or average signals from the population. Here, we use dichotomous
female phonotaxis choice tests to determine how the value of male call embellishment varies across 20 individual males frogs
recorded from the wild—a sample which captures the acoustic diversity present in the population. We tested 20 females for
each male call pair (i.e., 400 females). The results show widespread preference amongst females for ornamented calls (“whine–chucks”)
over simple calls (“whines”), yet also demonstrate substantial variation in the relative benefits for individual male frogs—some
males enjoy appreciable benefits by using ornaments while others (30% of males in this study) do not. We also show that the
relative amplitude of the chuck to the whine correlates positively with the value of call elaborations across these 20 males.
Finally, by manipulating the relative amplitude of whines and chucks using both natural and synthetic calls, we demonstrate
directly that this single call parameter is key to determining the relative value of call elaborations across males. 相似文献
We measured the concentrations and depth distribution (0-10, 10-20 cm) of 31 PAHs and 12 OPAHs in soils at eleven equidistant sampling points along a 20-km transect in the Angren industrial region (coal mine, power plant, rubber factory, gold mine), Uzbekistan to gain an insight into their concentrations, sources, and fate. Concentrations of all compounds were mostly much higher in the 0-10 cm than in the 10-20 cm layer except in disturbed soil close to the coal mine. Proximity to one of the industrial emitters was the main determinant of PAH and OPAH concentrations. The ∑31PAHs concentrations correlated positively with the ∑7 carbonyl-OPAH (r = 0.98, p < 0.01), ∑5 hydroxyl-OPAH (r = 0.72, p < 0.05), and with industrially emitted trace metals in the topsoil, identifying industrial emissions as their common source. Concentrations of several OPAHs were higher than their parent PAHs, but their vertical distribution in soil suggested only little higher mobility of OPAHs than their corresponding parent PAHs. 相似文献
In order to understand the processes of stone formation, compositional, spectroscopic, mineralogical and crystallographic characteristics of human urinary stones collected from patients in Sri Lanka were investigated in detail. The data showed that the majority of urinary calculi were calcium oxalate, either whewellite or weddellite. Other solid phases of stones were composed of struvite, uricite and hydroxylapatite. However, mixed compositions were common except for whewellite stones which occur frequently in pure form. Scanning electron microscope observations and associated energy-dispersive X-ray analyses revealed that whewellite or weddellite was well crystalized compared to other stones types, while phosphate stones were mostly cryptocrystalline. The average δ13C and δ18O of stones were − 32.2‰ (− 37.3 to − 17.4‰) and − 24.2‰ (− 26.7‰ to − 8.9‰), respectively. The δ13C values were highly depleted compared to North American and European urinary stones. This may be due to food habits of Asians who consume rice as the staple food.
Social structure emerges from the patterning of interactions between individuals and plays a critical role in shaping some of the main characteristics of animal populations. The topological features of social structure, such as the extent to which individuals interact in clusters, can influence many biologically important factors, including the persistence of cooperation, and the rate of spread of disease. Yet, the extent to which social structure topology fluctuates over relatively short periods of time in relation to social, demographic, or environmental events remains unclear. Here, we use social network analysis to examine seasonal changes in the topology of social structures that emerge from socio-positive associations in adult female rhesus macaques (Macaca mulatta). Behavioral data for two different association types (grooming and spatial proximity) were collected for females in two free-ranging groups during two seasons: the mating and birth seasons. Stronger dyadic bonds resulted in social structures that were more tightly connected (i.e., of greater density) in the mating season compared to the birth season. Social structures were also more centralized around a subset of individuals and more clustered in the mating season than those in the birth season, although the latter differences were mostly driven by differences in density alone. Our results suggest a degree of temporal variation in the topological features of social structure in this population. Such variation may feed back on interactions, hence affecting the behaviors of individuals, and may therefore be important to take into account in studies of animal behavior. 相似文献