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171.
Summary Components of the green leaf volatile complex (Z-3-hexenyl acetate andE-2-hexenyl acetate) were shown to enhance responses of tobacco budworm,Heliothis virescens, males to the sex attractant pheromone of conspecific females in the field. The results are discussed with regard to green leaf volatiles which enhance the attractant pheromone of a cohabiting species, and serve as attractants of a parasitoid of conspecific larvae. 相似文献
172.
Assessment of patch quality by ladybirds: relative response to conspecific and heterospecific larval tracks a consequence of habitat similarity? 总被引:2,自引:0,他引:2
Alexandra Magro Joseph N. Téné Nicolas Bastin Anthony F. G. Dixon Jean-Louis Hemptinne 《Chemoecology》2007,17(1):37-45
Summary. Aphid colonies can reach high levels of abundance but last for short periods of time. The larvae of aphidophagous ladybirds
(Coleoptera: Coccinellidae) that feed on these colonies might therefore suffer from starvation, which favours the occurrence
of cannibalism and intraguild predation. Thus, the assessment of patch quality becomes crucial and it has been shown that
female ladybirds refrain from laying eggs in the presence of an oviposition deterring semiochemical deposited by their larvae.
Adalia bipunctata (L.), Adalia decempunctata (L.) and Coccinella septempunctata L. are 3 sympatric species of ladybirds, which can co-occur in aphid colonies. As a consequence, their eggs and larvae are
under threat, not only from cannibalism but also intraguild predation. Females should, therefore, also use the tracks deposited
by heterospecific larvae to assess the quality of aphid colonies as oviposition sites. The expectation is that: 1- the strength
of the reaction to each other’s larval tracks should be correlated with percentage habitat overlap and that 2- the reaction
to conspecific larval tracks should be stronger than to heterospecific tracks. In order to test these hypotheses, females’
oviposition behaviour was analysed and a chemical analysis of the tracks of their larvae undertaken.
The results show that oviposition behaviour is not related to habitat overlap. Both species of Adalia react to tracks of their own larvae and those of C. septempunctata, but A. decempunctata reacted more strongly than A. bipunctata. C. septempunctata reacted very slightly to its own tracks but not to those of either species of Adalia.
The larval tracks are mainly composed of alkanes. Those of the two species of Adalia are qualitatively 100% similar and 60% so when the quantitative results are compared. They are, however, only 24–29% similar
to those of Coccinella septempunctata. 相似文献
173.
Joseph M. Wunderle Jr. María Santa Castro N. Fetcher 《Behavioral ecology and sociobiology》1987,21(4):249-255
Summary Adult bananaquits on negative energy budgets were presented with a patch containing two flower types with identical mean rewards, but different variances. The flower patch contained a random array of 85 yellow and 85 red artificial flowers. Flowers of one color were filled with the same quantity of nectar (constant flowers); flowers of the other color were filled with variable quantities of nectar (variable flowers). In the first series of experiments the birds were given three presentations, followed by three more presentations with the flower colors reversed, to control for color preferences. Some individuals were occasionally indifferent during a presentation, but overall the birds significantly preferred the constant flowers. In the second series of experiments two birds were give five presentations of the floral patch during a day at a rate less than minimally required to meet all 24-h energy costs. In all experiments, bananaquits on negative energy budgets were either indifferent or risk-averse, but never risk-prone. The absence of risk-prone foraging might be attributed to resource dispersion pattern, reward skew, or a species characteristic. 相似文献
174.
Donald C. Dearborn Angela D. Anders Joseph B. Williams 《Behavioral ecology and sociobiology》2005,58(4):397-406
We used detailed time-budget observations, mark-resight data, and doubly labeled water estimates of energy expenditure to test whether energy spent on courtship display by male frigatebirds functions as a sexually selected handicap signal. During a 2-day period of time budget observations, males displayed on average 29.5% of the time (range 0–100% for 15 different males), and this value was correlated with an index of season-long display effort. Season-long display effort was strongly predictive of pairing success. Average field metabolic rate (FMR) during the 2-day time budget period was 676.5 kJ/day (range 464.8–1035.0), substantially lower than the mass-specific FMR predicted from studies of other seabirds during incubation or chick-rearing. Despite a low overall FMR, display effort could function as an energetic handicap, either if FMR correlates positively with the amount of courtship performed or if high-quality males display at a high rate because they pay a lower energy cost per unit of display than do low-quality males. We found no relationship between FMR and display rate, despite good power for doing so. We also did not find a significant difference in energy spent divided by courtship time for males that were or were not chosen by females (inferred to be high- and low-quality males, respectively), though the medians differed in the predicted direction (preferred males having lower relative costs than non-preferred males) and the confidence interval on the difference between groups was very wide. Thus, we found evidence that male courtship effort is predictive of pairing success, we rejected one mechanism by which energetic cost of display could function as a handicap, and our test of the alternate energetic handicap mechanism was equivocal. 相似文献
175.
There has now been an abundance of research conducted to explore genetic bases that underlie learning performance in the honey bee (Apis mellifera). This work has progressed to the point where studies now seek to relate genetic traits that underlie learning ability to learning in field-based foraging problems faced by workers. Accordingly, the focus of our research is to explore the correlation between laboratory-based performance using an established learning paradigm and field-based foraging behavior. To evaluate learning ability, selected lines were established by evaluating queens and drones in a proboscis extension reflex (PER) conditioning procedure to measure learning in a laboratory paradigm—latent inhibition (LI). Hybrid queens were then produced from our lines selected for high and low levels of LI and inseminated with semen from many drones chosen at random. The genetically diverse worker progeny were then evaluated for expression of LI and for preference of pollen and/or nectar during foraging. Foragers from several different queens, and which had resulted from fertilization by any of several different drone fathers, were collected as they returned from foraging flights and analyzed for pollen and nectar contents. They were subsequently evaluated for expression of LI. Our research revealed that pollen foragers exhibited stronger learning, both in the presence (excitatory conditioning) and absence (LI) of reinforcement. The heightened overall learning ability demonstrated by pollen foragers suggests that pollen foragers are in general more sensitive to a large number of environmental stimuli. This mechanism could contribute toward explanations of colony-level regulation of foraging patterns among workers.Communicated by R. Page 相似文献
176.
Joseph N. Lekakis 《Environmental management》1998,22(1):1-8
/ Collaboration of countries with an aim to share fresh surface water resources promises to generate potential joint benefits. Unfortunately, existing agreements lack the perspective and capacity to produce any real action in efficient cross-border water allocation. When that problem is encountered by any two adjacent countries claiming riparian rights to the same watercourse, this paper suggests that apossible solution to be examined is a water market. This market requires the relevant countries to engage in a bargaining process as described in the theory of bilateral monopoly. The bargaining process should determine both the water quantity to be transferred and the price to be paid. However, there has to be a fair allocation of the joint benefits resulting from the transfer for a sustainable price solution. As an empirical illustration, the paper examines the case of river Nestos shared by Bulgaria and Greece in the southern Balkans. A net revenue function quadratic in water is specified and estimated using scarce data on three agricultural crops in Greece. Sensitivity analysis on the size and distribution of the net benefits is also performed.KEY WORDS: Bilateral agreements; Water markets; Efficient allocation 相似文献
177.
Electric utility companies in the United States and Canada are participating in a unique environmental benchmarking program (EBP) designed to comparatively assess environmental performance. Each company annually provides data on emissionslwastes, compliance, and other environmental aspects to an independent consultant, Research Triangle Institute (RTI), whose staff compiles the data and computes approximately 80 discrete environmental performance metrics for each company. RTI provides a confidential report for each participant presenting the results of the assessment. In addition, RTI conducts a follow-up assessment to determine “best-practices” of each of the top performers for each metric. The EBP provides each participant with useful information on its strengths and weaknesses relative to the other companies in the program as well as ideas on how to improve its environmental performance. Annual participation in the program allows a company to measure improvement in performance on an annual basis. This article summarizes the evolution of the EBP and describes the study methods and reporting approach. Our goal in sharing this information is to demonstrate the usefulness of the program and encourage further participation by all major North American electric utilities. 相似文献
178.
Baselines for land-use change in the tropics: application to avoided deforestation projects 总被引:2,自引:0,他引:2
Sandra Brown Myrna Hall Ken Andrasko Fernando Ruiz Walter Marzoli Gabriela Guerrero Omar Masera Aaron Dushku Ben DeJong Joseph Cornell 《Mitigation and Adaptation Strategies for Global Change》2007,12(6):1001-1026
Although forest conservation activities, particularly in the tropics, offer significant potential for mitigating carbon (C)
emissions, these types of activities have faced obstacles in the policy arena caused by the difficulty in determining key
elements of the project cycle, particularly the baseline. A baseline for forest conservation has two main components: the
projected land-use change and the corresponding carbon stocks in applicable pools in vegetation and soil, with land-use change
being the most difficult to address analytically. In this paper we focus on developing and comparing three models, ranging
from relatively simple extrapolations of past trends in land use based on simple drivers such as population growth to more
complex extrapolations of past trends using spatially explicit models of land-use change driven by biophysical and socioeconomic
factors. The three models used for making baseline projections of tropical deforestation at the regional scale are: the Forest
Area Change (FAC) model, the Land Use and Carbon Sequestration (LUCS) model, and the Geographical Modeling (GEOMOD) model.
The models were used to project deforestation in six tropical regions that featured different ecological and socioeconomic
conditions, population dynamics, and uses of the land: (1) northern Belize; (2) Santa Cruz State, Bolivia; (3) Paraná State,
Brazil; (4) Campeche, Mexico; (5) Chiapas, Mexico; and (6) Michoacán, Mexico.
A comparison of all model outputs across all six regions shows that each model produced quite different deforestation baselines.
In general, the simplest FAC model, applied at the national administrative-unit scale, projected the highest amount of forest
loss (four out of six regions) and the LUCS model the least amount of loss (four out of five regions). Based on simulations
of GEOMOD, we found that readily observable physical and biological factors as well as distance to areas of past disturbance
were each about twice as important as either sociological/demographic or economic/infrastructure factors (less observable)
in explaining empirical land-use patterns.
We propose from the lessons learned, a methodology comprised of three main steps and six tasks can be used to begin developing
credible baselines. We also propose that the baselines be projected over a 10-year period because, although projections beyond
10 years are feasible, they are likely to be unrealistic for policy purposes. In the first step, an historic land-use change
and deforestation estimate is made by determining the analytic domain (size of the region relative to the size of proposed
project), obtaining historic data, analyzing candidate baseline drivers, and identifying three to four major drivers. In the
second step, a baseline of where deforestation is likely to occur–a potential land-use change (PLUC) map—is produced using
a spatial model such as GEOMOD that uses the key drivers from step one. Then rates of deforestation are projected over a 10-year
baseline period based on one of the three models. Using the PLUC maps, projected rates of deforestation, and carbon stock
estimates, baseline projections are developed that can be used for project GHG accounting and crediting purposes: The final
step proposes that, at agreed interval (e.g., about 10 years), the baseline assumptions about baseline drivers be re-assessed.
This step reviews the viability of the 10-year baseline in light of changes in one or more key baseline drivers (e.g., new
roads, new communities, new protected area, etc.). The potential land-use change map and estimates of rates of deforestation
could be re-done at the agreed interval, allowing the deforestation rates and changes in spatial drivers to be incorporated
into a defense of the existing baseline, or the derivation of a new baseline projection. 相似文献
179.
Chorionic villus sampling was performed between 7 and 12 weeks gestation in 1000 patients, 935 of whom intended to continue after fetal diagnosis. Transcervical and Transabdominal aspiration techniques were used providing a sampling success rate of 99 per cent. Anatomical and clinical contraindications to transcervical aspiration were pointed out, and the complementary role of the transabdominal approach evaluated. In the 615 concluded pregnancies an overall abortion rate of 4.1 per cent was observed. A significant association between fetal loss and number of catheter insertions was demonstrated. Bacterial inoculation by catheter insertion and colonization of uterine cavity was suspected as the cause of chorionamnionitis diagnosed in two cases (0.2 per cent) after CVS. Bleeding was the most frequent early complication (12.0 per cent) following chorionic aspiration, but was not significantly related to pregnancy wastage. Late complications, i.e. premature rupture of membranes (0.8 per cent), preterm delivery (6.3 per cent), perinatal losses (1.2 per cent), placental disorders (1.6 per cent), and congenital defects (2.6 per cent) did not exceed the expected values. Normal intrauterine growth patterns were ultrasonically estimated by cross-sectional and longitudinal studies, while the weight at birth was normally distributed in the range of the general population. 相似文献
180.
The effects of chloride, nitrate, perchlorate and sulfate ions on the rates of the decomposition of hydrogen peroxide and the oxidation of organic compounds by the Fenton's process have been investigated. Experiments were conducted in a batch reactor, in the dark at pH < or = 3.0 and at 25 degrees C. Data obtained from Fe(II)/H2O2 experiments with [Fe(II)]0/[H2O2]0 > or = 2 mol mol(-1), showed that the rates of reaction between Fe(II) and H2O2 followed the order SO4(2-) > ClO4(-) = NO3- = Cl-. For the Fe(III)/H2O2 process, identical rates were obtained in the presence of nitrate and perchlorate, whereas the presence of sulfate or chloride markedly decreased the rates of decomposition of H2O2 by Fe(III) and the rates of oxidation of atrazine ([atrazine]0 = 0.83 microM), 4-nitrophenol ([4-NP]0 = 1 mM) and acetic acid ([acetic acid]0 = 2 mM). These inhibitory effects have been attributed to a decrease of the rate of generation of hydroxyl radicals resulting from the formation of Fe(III) complexes and the formation of less reactive (SO4(*-)) or much less reactive (Cl2(*-)) inorganic radicals. 相似文献