Nest predation imposes a major cost to reproductive females, who should therefore take measures to avoid encounters with predators.
However, when predators are conspecifics, avoidance can be more difficult and may be a consequence of social or aggregative
behaviors. In this study, we measured the consequences of conspecific egg cannibalism on hatching success in the maritime
earwig (Anisolabis maritima), which occasionally form aggregations. We hypothesized that conspecific egg cannibalism is a byproduct of aggregation, and
that cannibalism rates would increase with aggregation density; however, our results do not support this. We combined field
data with a lab experiment to test the effectiveness of maternal nest defense in protecting nests from a conspecific. Nests
with a guard had higher hatching success and lower rates of cannibalism than unattended nests in the presence of a conspecific.
We also measured body and forcep size to see whether the outcome of contests was determined by relative size. Female guards
who were larger relative to the invading conspecific maintained their nest and had higher hatching success than females who
were relatively smaller, suggesting that the maritime earwig is under directional selection for larger body and/or forcep
size. 相似文献
The United Nations Climate Conference 25, held in December 2019, reached a significant agreement against implementing the Paris agreement come 2020. Bound by the contract, 189 countries who are party to the deal agreed to constrain worldwide temperature to ascend to 1.5° Celsius. To this end, the present study attempts to investigate the readiness of selected countries in the European Union to implement the agreement, which will better the quality of the global environment. In line with this, this study appraises the connection between economic growth, renewable and non-renewable energy consumption, on emissions in 11 countries in the European Union from 1990 to 2016. The study utilises the Pooled Mean Group-Auto Regressive Distributed Lag (PMG-ARDL) model estimator and Dumitrescu and Hurlin Panel Causality analysis to analyse the long-run and short-run impact and direction of causality among these factors, respectively. The long-run study's empirical results show a U-shaped Environmental Kuznets Curve (EKC) and a negative connection between renewable energy use and emissions in the EU-11 countries. In the short-run, non-renewable energy use worsens CO2 emissions while renewable energy use leads to a fall in emissions. Similarly, causality tests show a feedback mechanism between emissions and renewable energy use and between non-renewable energy and renewable use. Also, there is unidirectional causality from income to CO2 emissions, non-renewable energy use to CO2 emissions. The investigation recommends an expanded proportion of renewable energy sources in the EU countries’ energy mix to cut down on emissions.
Environmental Science and Pollution Research - In recent times, the persistent global environmental challenges have paved the way for the underpinning of climate change within the perspective of... 相似文献
Environmental Science and Pollution Research - Considering the prevailing wave of global warming and other environmental challenges, which can be attributed to increasing environmental pollution as... 相似文献
Out study deals with the demand for water and alternative agricultural production and land use patterns under varying prices for both surface and ground water. We derive irrigation water demands for both the United States and regions of it. Not only is a different amount of water used at each set of water prices but also a different mix of crops, livestock, and production technology develops among the different regions. Under the highest set of prices used, more than fourteen million acres are converted into dryland farming. Total irrigated water use decreases by more than 25 million acre-feet. Irrigated crop yields are reduced and cropping patterns shift away from irrigation. Commodity shadow prices increase as much as 15 percent under high prices for both surface and ground water. A redistribution of farm income occurs between irrigated and dryland regions. 相似文献
We create a proxy for the cost of irrigation water in Georgia from a sample of Georgia irrigators by investigating the marginal cost of pumping groundwater. We then combine this proxy with agronomic and climatic variables to estimate the response of agricultural water use to differences in the marginal cost of irrigation. The results show that pumping costs are a significant determinant of water use, and imply that agricultural water use would be moderately affected by institutional changes that would explicitly price water. 相似文献
Nucleation of polylactide and polypropylene using novel renewable resource biobased carbon nanospheres (CNS) is investigated
using differential scanning calorimetry and polarized optical microscopy. Isothermal studies near the optimal crystallization
temperature demonstrate at least a five-fold increase in crystallization rate in PP but only a 1.4 times faster crystallization
in PLA. Non-isothermal studies reveal an asymptotic relationship of the maximum crystallization temperature with increasing
CNS weight loading in PP and no relationship in PLA. Microscopy indicates some aggregation in the solution blended samples
and that average spherulite size is reduced 10-fold due to faster nucleation in the composites as compared to the neat polymer.
The fractional crystallinity achieved during non-isothermal crystallization increases by about 7% with addition of a small
amount of CNS and decreases with weight loading higher than 1%. The crystallization rates obtained in polypropylene are competitive
with widely used mineral talc nucleating agents. 相似文献