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31.
Rickey D. Cothran Andy R. Stiff Kristopher Chapman Gary A. Wellborn Rick A. Relyea 《Behavioral ecology and sociobiology》2013,67(8):1357-1367
Many species experience reproductive interference defined as interspecific mating interactions that reduce the fitness of individuals in at least one of the species. We examined reproductive interference among three cryptic amphipod species that co-occur in the vegetated zone of lakes. Because these animals form precopulatory pairs and males commonly have indiscriminant mating behavior, we predicted that (1) there would be interspecific pairing, (2) interspecific pairing would be more common when conspecifics were rare, and (3) interspecific pairing would be more common in species combinations where males are larger than females. Using color phenotypes to distinguish species, a novel discovery reported here, we conducted experiments to evaluate patterns of interspecific pairing. In a no-choice experiment (i.e., amphipods had access to mates of only one species), we observed a low rate (5 %) of interspecific pairing and 80 % of these cases involved males that were larger than females. In a second experiment where individuals had access to conspecific mates at varying relative abundance, only 0.04 % of the pairs observed were between heterospecifics, suggesting that the interspecific pairing observed in the no-choice experiment was an artifact of not having access to conspecific mates. Our results suggest that at least one sex has sufficient species-recognition abilities to circumvent the formation of interspecific pairs; therefore, reproductive interference may be minimal in these species. 相似文献
32.
Ben B. Chapman Lesley J. Morrell Jens Krause 《Behavioral ecology and sociobiology》2009,63(12):1757-1763
The environment is profoundly important in shaping many aspects of animal phenotype, including courtship and mating behaviours.
Courtship displays rely upon the transmission of visual information from the signaller to the receiver, which means they are
likely to be less effective in visually poor conditions such as at low light or in turbid ecosystems. One might therefore
predict that in visually poor environments it would be beneficial for individuals to plastically adjust their mating behaviour
to maximise mating success. Here, we investigate the impact of the developmental and current visual environment (light intensity)
upon male mating behaviour in the Trinidadian guppy Poecilia reticulata. Male guppies have two different mating tactics: They can court females with a visual sigmoid display or attempt to circumvent
female choice by attempting a non-consensual copulation (gonapodium thrust). We reared juvenile guppies in low light and relatively
high light intensities for 5 months before observing individual males for mating behaviour in both light conditions. We found
that the current light environment is important in determining the frequency of both sigmoidal courtship displays and non-consensual
copulation attempts. Males increase the frequency of sigmoidal displays at relatively high light and increase non-consensual
mating attempts at low light, suggesting that males compensate for poor visual conditions via an adjustment in tactics. We
also find a significant correlation in courtship effort between the different light environments, suggesting that there is
individual consistency across time and context for this trait. Developmental environment was less important. However, we found
that fish reared at lower light intensities continued to employ sigmoidal displays despite the poor current visual environment.
Our data show that male mating behaviour is phenotypically plastic in response to recent light environment. This may have
implications for understanding how animals cope with anthropogenic environmental change. 相似文献
33.
Gasification of solid waste for energy has significant potential given an abundant feed supply and strong policy drivers. Nonetheless, significant ambiguities in the knowledge base are apparent. Consequently this study investigates sulphur mechanisms within a novel two stage fluid bed-plasma gasification process. This paper includes a detailed review of gasification and plasma fundamentals in relation to the specific process, along with insight on MSW based feedstock properties and sulphur pollutant therein. As a first step to understanding sulphur partitioning and speciation within the process, thermodynamic modelling of the fluid bed stage has been performed. Preliminary findings, supported by plant experience, indicate the prominence of solid phase sulphur species (as opposed to H2S) - Na and K based species in particular. Work is underway to further investigate and validate this. 相似文献
34.
35.
Salerno Jonathan Chapman Colin A. Diem Jeremy E. Dowhaniuk Nicholas Goldman Abraham MacKenzie Catrina A. Omeja Patrick Aria Palace Michael W. Reyna-Hurtado Rafael Ryan Sadie J. Hartter Joel 《Regional Environmental Change》2018,18(3):913-928
Regional Environmental Change - Landscapes are changing rapidly in regions where rural people live adjacent to protected parks and reserves. This is the case in highland East Africa, where many... 相似文献
36.
ABSTRACTRecent research has allowed us to quantify the costs and benefits of adopting renewable energy in specific municipalities, but how do these outcomes vary among communities at the national scale? This study uses survey responses from 47 Japanese municipalities to model these impacts and identifies key technological, social, and demographic factors that shape which communities benefit more from the renewable energy transition. On average, introducing renewable energy improves social equity, any financial burden on electricity prices is born most by wealthier residents, not the poor, and towns are predisposed to benefit from renewables no matter the amount introduced. To improve these impacts, towns can increase the amount of solar they host, or they can adjust the amount of CO2 emissions, PM emissions, tax revenue, jobs gained, or unpopular renewable power plants in their town. However, preferences and demographics matter as well. Age, education, and local preferences in favor of employment and community development all significantly relate to equity potential outcomes. Policymakers should consider adjusting their local energy priorities using these levers if they hope to engineer a renewable energy transition that is both positive and popular for their constituents. 相似文献
37.
Cladocerans (or water-fleas) are important animals in freshwater exosystems. They are widely used in toxicity tests because of their small size, ease of culture, and sensitivity to chemicals. They are particularly suited to life-cycle tests because newly-hatched young can produce offspring in less than one week. Most data are available for European and North American species, and may be not be appropriate to Australian conditions. In the present study, eight Australian cladocerans were evaluated in three-brood life-cycle tests over ten days or less. Species were evaluated by duration of life cycle, ease of handling, numbers of young produced in three broods, and stability in laboratory culture.Ceriodaphnia cfdubia was the best test species. The greatest number of young, the highest survival rate and the shortest time to produce three broods were achieved in filtered Sydney mains water, aged in the presence of fish, using blended trout pellets and alfalfa as food. 相似文献
38.
During oil and gas production, water is often extracted from geological formations along with the hydrocarbons. These "produced
waters" have been discharged to Nueces Bay since the turn of the century. These effluents were found to be highly toxic, and
sediments in the vicinity of the discharges were also toxic. We developed a map of wells and produced-water discharge sites
in the vicinity of Nueces Bay and identified numerous unplugged wells suitable for conversion to produced water disposal wells.
An economic analysis of conversion to subterranean injection of produced water indicates that most of the wells currently
in production could pay out the cost of conversion to injection in one to three years. The use of one injection well for two
or more water-producing wells could yield greater savings. Wells that could not support the cost of injection are small producers,
and their loss would not constitute a major loss of jobs or dollars to the area. This study could serve as a useful model
for evaluating the economic feasibility of conversion to injection in other areas of Texas and Louisiana. 相似文献
39.
The ultraplankton (cell diameters >3 μm), which compromises about 70% of the biomass of phytoplankton in subtropical surface waters near Oahu, Hawaii, was isolated for growth rate studies. The specific growth rate (μ) was estimated from the rate of increase of the chlorophyll biomass during incubations in the absence of grazers. This growth rate of the ultraplankton ranged from 0.037 to 0.071 h?1 (=1.3 to 2.5 doublings d?1) during a period when P:B ratios of 5 to 14.5 μg C μg?1 chl a h?1 prevailed. The co-occurrence of atypically high P:B ratios and nonlimiting ambient nutrient concentrations suggests that the calculated values are higher than those characteristic of such subtropical ecosystems in general. Rates of ammonium uptake and photosynthesis by the >3 μm fraction were also compared to those of larger fractions. Organisms in the >3 μm fraction assimilated NH 4 + at a rate which was about 75% greater than that of the 3 to 20 μm size fraction. Comparison of μ and P:B data collected over a 2 mo period (November–December, 1980) shows that the correlation between these two rate indices is nonlinear. The predominance of small-celled phytoplankton in oligotrophic waters is explained, in part, by its higher μ, its higher nutrient assimilation rates, and the absence of its loss through sedimentation. 相似文献
40.
Seasonal growth in Laminaria longicruris: Relations with dissolved inorganic nutrients and internal reserves of nitrogen 总被引:5,自引:0,他引:5
Observations have been made on seasonal fluctuations in dissolved inorganic nutrients, internal reserves of nitrogen and growth rates in Laminaria longicruris. The onset of winter growth in shallow-water stations (6 and 9 m) correlated well with improved dissolved nitrate conditions in the sea. During the winter, reserves of NO
3
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were accumulated by the plants and reached maximum values of 150 moles per g fresh weight in March. This represents a concentration factor of approximately 28,000 over the ambient levels, or an internal nitrogen reserve of 2.1% of the dry weight of the tissue. Depletion of this nitrogen pool followed the disappearance of the external NO
3
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with a lag period of up to 2 months. Rapid kelp growth was measured during this period. Reserves of organic nitrogen also reached maximum values in March and declined slowly throughout the summer into autumn. It is suggested that the combined inorganic and organic nitrogen reserves sustain the rapid growth rates into July and at reduced rate through the late summer. Fertilization of an experimental perimental kelp bed with NaNO3 increased the internal plant reserves of NO
3
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and produced a much improved summer growth rate. The enriched plants developed very small reserves of carbohydrate during the rapid summer growth phase.NRCC No. 15549. 相似文献