Fishing for Prawn Larvae in Bangladesh: An Important Coastal Livelihood Causing Negative Effects on the Environment

Freshwater prawn (Macrobrachium rosenbergii) farming in Bangladesh has, to a large extent, been dependent on the supply of wild larvae. Although there are 81 freshwater prawn hatcheries in the country, a lack of technical knowledge, inadequate skilled manpower, and an insufficient supply of wild broods have limited hatchery production. Many thousands of coastal poor people, including women, are engaged in fishing for wild prawn larvae along the coastline during a few months each year. On average, 40% of the total yearly income for these people comes from prawn larvae fishing activity. However, indiscriminate fishing of wild larvae, with high levels of bycatch of juvenile fish and crustaceans, may impact negatively on production and biodiversity in coastal ecosystems. This concern has provoked the imposition of restrictions on larvae collection. The ban has, however, not been firmly enforced because of the limited availability of hatchery-raised larvae, the lack of an alternative livelihood for people involved in larvae fishing, and weak enforcement power. This article discusses the environmental and social consequences of prawn larvae fishing and concludes that, by increasing awareness among fry fishers, improving fishing techniques (reducing bycatch mortality), and improving the survival of fry in the market chain, a temporal ban may be a prudent measure when considering the potential negative impacts of bycatch. However, it also suggests that more research is needed to find out about the impact of larvae fishing on nontarget organisms and on the populations of targeted species.     

Bioaccumulation of trace elements in omnivorous amphibian larvae: implications for amphibian health and contaminant transport

Despite the influence that amphibians have on the flow of energy and nutrients in ecological systems, the role that amphibians play in transporting contaminants through food webs has received very little attention. This study was undertaken to investigate bioaccumulation of trace elements in amphibians relative to other small aquatic organisms in a contaminated wetland. We collected bullfrog larvae (Rana catesbeiana) along with three other species of small vertebrates and four species of invertebrates from a site contaminated with a wide array of trace elements and analyzed them for trace element concentrations and stable nitrogen and carbon isotope composition. We found that amphibian larvae accumulated the highest concentrations of most trace elements, possibly due to their feeding ecology. These results suggest that omnivorous amphibian larvae can serve as a critical link for trace element trophic transfer. Their propensity to accumulate trace elements may have important implications for amphibian health in contaminated environments and should be further investigated.     

Forest ecosystems and the changing patterns of nitrogen input and acid deposition today and in the future based on a scenario

A global assessment of the impact of the anthropogenic perturbation of the nitrogen and sulfur cycles on forest ecosystems is carried out for both the present-day [1980-1990] and for a projection into the future [2040-2050] under a scenario of economic development which represents a medium path of development according to expert guess [IPCC IS92a]. Results show that forest soils will receive considerably increasing loads of nitrogen and acid deposition and that deposition patterns are likely to change. The regions which are most prone to depletion of soils buffering capacity and supercritical nitrogen deposition are identified in the subtropical and tropical regions of South America and Southeast Asia apart from the well known 'hotspots' North-Eastern America and Central Europe. The forest areas likely to meet these two risks are still a minor fraction of the global forest ecosystems, though. But the bias between eutrophication and acidification will become greater and an enhanced growth triggered by the fertilizing effects of increasing nitrogen input cannot be balanced by the forest soils nutrient pools. Results show increasing loads into forest ecosystems which are likely to account for 46% higher acid loads and 36% higher nitrogen loads in relation to the 1980-1990 situation. Global background deposition of up to 5 kg N ha-1 a-1 will be exceeded at more than 25% of global forest ecosystems and at more than 50% of forest ecosystems on acid sensitive soils. More than 33% of forest ecosystems on acid sensitive soils will receive acid loads which exceeds their buffering capacity. About 25% of forest areas with exceeded acid loads will receive critical nitrogen loads.     

Evaluation of a biomarker of Cd(II) exposure on Limnoperna fortunei

The use of organisms to monitor contamination allows the access to information that cannot be acquired by chemical methods. Limnoperna fortunei, mussel frequently found in Río de la Plata estuary, fulfils the requirements to be used as a biomonitoring organism. In this work we report that a polypeptide of 22 kDa of molecular weight (LF22) is induced when L. fortunei is exposed to Cd (II), Cu(II) and Hg(II) sublethal levels. To characterize LF22, mussels were sampled from a non-polluted region and whole soft tissue was homogenized, with and without previous exposure to 100 microg/L of Cd(II). The cytosolic proteins were evaluated by mono and bidimensional SDS-PAGE, and size exclusion chromatography. All the methods showed that LF22 triples its concentration in presence of Cd(II). Purification of LF22 was achieved by fractioned precipitation, salting-out, ionic exchange and size exclusion chromatography. We conclude that LF22 is a useful biomarker of heavy metal exposure.     

Inter- and intra-specific variation on sensitivity of larval amphibians to nitrite

Several authors have suggested that nitrogen-based fertilizers may be contributing to the global amphibian decline. We have studied the impact of sodium nitrite on early aquatic stages of Epidalea calamita, Pelophylax perezi and Hyla meridionalis larvae from Do?ana National Park (coastal wetland) and P. perezi from Gredos Mountain (high mountain ponds), exposed during 10 to 16 days. After 8 days of exposure all P. perezi larvae from Do?ana presented 100% mortality at 5 mg l(-1)N-NO2(-) while E. calamita larvae mortality rates were significantly lower at that concentration after 15 days. However, for H. meridionalis at day 15 no deaths were registered at 5 mg l(-1)N-NO2(-) and at 20 mg l(-1)N-NO2(-) presented intermediate mortality rates. In Do?ana the 10 d LC50 of older H. meridionalis larvae was between 20 and 30 mg l(-1)N-NO2(-) whilst for P. perezi it was below 5 mg l(-1)N-NO2(-). These results indicate inter-specific variation of the sensitivity of larval amphibians to nitrite. Gredos Mountain P. perezi larvae exposed since the egg stage were highly sensitive to nitrite, with a 16 d LC50 below 0.5 mg l(-1)N-NO2(-). The same species in Do?ana had a 15 d LC50 between 5 and mg l(-1)N-NO2(-). These results suggest that there is also intra-specific variation in sensitivity of amphibian larvae to nitrite: mountain amphibian populations appear to be more sensitive to polluted environments than coastal populations. Geographic and genetic variation and evolutionary adaptation of tolerance may also be the keys to variation amongst populations of the same species.     

Lethal and sub-lethal effects of the fungicide chlorothalonil on three life stages of the grass shrimp,Palaemonetes pugio

Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is the second most widely used fungicide in the United States. Due to the widespread use of chlorothalonil, it is important to investigate the effects chlorothalonil may have on estuarine species such as the grass shrimp, Palaemonetes pugio. This study examined the toxicity of chlorothalonil to three life-history stages (embryo, larvae, adult) of the grass shrimp. Also, molting frequency, growth response and metamorphosis from a larval life cycle pulsed exposure assay were examined as sub-lethal indicators of chlorothalonil exposure. Results showed embryos were the least sensitive with a 96-h Median Lethal Concentration (LC50) of 396.0 microg/L (95% Confidence Interval [CI] 331.3-472.4 microg/L). The adult 96-h LC50 was 152.9 microg/L (95% CI 120.3-194.5 microg/L). Larvae were the most sensitive to chlorothalonil exposure with a 96-h LC50 of 49.5 microg/L (95% CI 44.4-55.27 microg/L). In the life cycle pulsed exposure assay, all surviving larvae in the treatments required significantly more molts to reach postlarvae than the control. Other measured parameters showed differences between treatments and control but there was no statistical significance. This research demonstrated that chlorothalonil is highly toxic to grass shrimp and that larval grass shrimp would be the most appropriate life stage to use for chlorothalonil risk assessments since that stage is the most sensitive.     

Toxic Effects of Crude Oil Combined with Oil Cleaner Simple Green on Yolk-sac Larvae and Adult Rainbow Trout Oncorhynchus mykiss (4 pp)

Background, Goal and Scope Cleaner CRYSTAL Simple Green (SG) was used for the cleanup of the oil spill in the Baltic Sea near Lithuania in 2001. No scientific data are available on the effects and consequences of its application for local aquatic life. The aim of this study was to determine and compare sublethal effects of a) solution SG; b) crude oil alone; c) SG in combination with oil on rainbow trout Oncorhynchus mykiss at different stages of its development in laboratory conditions.Methods Laboratory studies were performed on adult rainbow trout (4-day duration) and on yolk-sac larvae (25-day duration) evaluating their biological parameters. Concentrations of water-soluble and thin-dispersed fractions of petroleum hydrocarbons were measured using gas chromatography.Results and Discussion SG solution (0.5 mg/l) did not affect the survival of larvae and adult fish, and no significant changes were determined in respiratory parameters of the exposed larvae and adult fish. The most expressed alterations were found in morphological parameters (a decrease in the average body mass) of larvae and in haematological indices (a decrease in the leukocyte count) of adult fish at the end of the tests. Crude oil (1610 mg/l) did not affect the survival of adult fish during the 4-day exposure. An increase in larvae mortality rate (~ 36%) was recorded at the end of the tests. A significant decrease in the average body mass and heart rate of larvae as well as in gill ventilation frequency of larvae and adult fish were determined. SG combined with oil induced an increase in larval mortality  46% of individuals died at the end of the tests. No mortality was recorded in adult fish. The average body mass and heart rate of larvae were significantly decreased. Marked changes were also found in respiratory parameters (gill ventilation frequency of larvae and adult fish significantly decreased, while “coughing” rate increased). A 1-day, 2-day exposure of fish to SG combined with oil induced a significant decrease in the leukocyte count of adult fish, which was also determined at the end of the tests. The augmentation of adverse impact could be explained by the data obtained from our studies. When SG was added into dilution water with crude oil the concentration of petroleum hydrocarbons in the mixture increased 3 ~ 4.5 times after 24 h and 96 h, respectively. Conclusions The comparative study of the effects of crude oil alone, SG and SG combined with oil showed that their toxic effects on fish differed. Oil combined with SG was found to be more toxic to fish (larvae and adults) than SG alone and oil alone. Fish at early stages of development (yolk-sac larvae) were more sensitive to the effects of the compounds studied than adults.Recommendations and Outlook To diminish the negative impact of oil spill cleanup using chemicals on aquatic ecosystems, it is recommended to carry out more comprehensive studies of their effects and after-effects in laboratory conditions using a wide scale of local aquatic organisms. The selected species of the most sensitive aquatic organisms should include those which are unable to escape the impact of combined action of oil and cleaners. Special attention should be directed to the research of effects of these pollutants on studied organisms at their most sensitive stages of life (reproduction, hatching, early stages of development), as after-effects of exposure to pollutants may be observed in future generations.     

Linking Climate Trends to Population Dynamics in the Baltic Ringed Seal: Impacts of Historical and Future Winter Temperatures

A global trend of a warming climate may seriously affect species dependent on sea ice. We investigated the impact of climate on the Baltic ringed seals (Phoca hispida botnica), using historical and future climatological time series. Availability of suitable breeding ice is known to affect pup survival. We used detailed information on how winter temperatures affect the extent of breeding ice and a climatological model (RCA3) to project the expected effects on the Baltic ringed seal population. The population comprises of three sub-populations, and our simulations suggest that all of them will experience severely hampered growth rates during the coming 90 years. The projected 30 730 seals at the end of the twenty-first century constitutes only 16 % of the historical population size, and thus reduced ice cover alone will severely limit their growth rate. This adds burden to a species already haunted by other anthropogenic impacts.     

On-road traffic emissions in a megacity

A new annual bottom–up emission inventory of criteria pollutants and greenhouse gases from on-road mobile sources was developed for 2006 for the metropolitan area of Buenos Aires, Argentina, within a four-year regional project aimed at providing tools for chemical weather forecast in South America. Under the scarcity of local emission factors, we collected data from measuring campaigns performed in Argentina, Brazil, Chile and Colombia and compiled a data set of regional emission factors representative of Latin American fleets and driving conditions. The estimated emissions were validated with respect to downscaled national estimates and the EDGAR global emission database. Our results highlight the role of older technologies accounting in average for almost 80% of the emissions of all species. The area exhibits higher specific emissions than developed countries, with figures two times higher for criteria pollutants. We analyzed the effect on emissions of replacing gasoline by compressed natural gas, occurring in Argentina since 1995. We identified (i) a relationship between number of vehicles and a compound socioeconomic indicator, and (ii) time-lags in vehicle technologies between developed and developing countries, which can be respectively applied for spatial disaggregation and the development of projections for other Latin American cities. The results may also be employed to complement global emission inventories and by local policy makers as an environmental management tool.     

Do parks work? Impact of protected areas on land cover clearing

This paper evaluates the impact of protected areas on land-cover clearing, using a metadata analysis of information on 49 locations from 22 countries. Protected areas had significantly lower rates of clearing in comparison to their surroundings. In addition, protected areas had also significantly lowered rates of clearing within their boundary following initiation of protection. Thus, protected areas do appear to be effective at limiting overall land-cover clearing. There was some variation in the rates of clearing across regions, where most protected areas from North America and Europe showed positive rates of land-cover change, while protected areas from Asia had the highest rates of land-cover clearing. While most protected areas from North America and Europe involved a relatively smaller number of actors, a greater number of actors and drivers of clearing was implicated in protected areas from Asia, Africa, and Latin America, indicating the increased difficulties faced by park management in these regions. In contrast, country income levels and the International Union for the Conservation of Nature and Natural Resources category of protection did not appear to impact the likelihood of land-cover clearing in protected areas.     

Toxicity of the mosquito control pesticide Scourge to adult and larval grass shrimp (Palaemonetes pugio)

This study investigated the toxicity of various concentrations of technical resmethrin and Scourge on adult and larval Palaemonetes pugio, a common grass shrimp species. Two types of tests were conducted for each of the resmethrin formulations using adult and larval grass shrimp life stages, a 96-h static renewal aqueous test without sediment, and a 24-h static nonrenewal aqueous test with sediment. For resmethrin, the 96-h aqueous LC50 value for adult shrimp was 0.53 microg/L (95% confidence interval (CI): 0.46-0.60 microg/L), and for larval shrimp was 0.35 microg/L (95% CI: 0.28-0.42 microg/L). In the presence of sediment, technical resmethrin produced a 24-h LC50 value for adult shrimp of 5.44 microg/L (95% CI: 4.52-6.55 microg/L), and for larval shrimp of 2.15 microg/L (95% CI: 1.35-3.43 microg/L). For Scourge, the 96-h aqueous LC50 for adult shrimp was 2.08 microg/L (95% CI: 1.70-2.54 microg/L), and for larval shrimp was 0.36 microg/L (95% CI: 0.24-0.55 microg/L). The 24-h sediment test yielded an LC50 value of 16.12 microg/L (95% CI: 14.79-17.57 microg/L) for adult shrimp, and 14.16 microg/L (95% CI: 12.21-16.43 microg/L) for larvae. Adjusted LC50 values to reflect the 18% resmethrin concentration in Scourge are 0.37 microg/L (adult), 0.07 microg/L (larvae) for the 96-h aqueous test, and 2.90 microg/L (adult), 2.6 microg/L (larvae) for the 24-h sediment test. Larval grass shrimp were more sensitive to technical resmethrin and Scourge than the adult life stage. The results also demonstrate that synergized resmethrin is more toxic to P. pugio than the nonsynergized form, and that the presence of sediment decreases the toxicity of both resmethrin and Scourge.     

Influence of ozone air pollution on plant-herbivore interactions. Part 2: Effects of ozone on feeding preference, growth and consumption rates of monarch butterflies (Danaus plexippus)

Effects of ozone fumigation of Asclepias curassavica L. and A. syriaca L. on feeding preference, growth, development, and nutritional indices of monarch larvae were investigated in conjunction with changes in specific leaf metabolites. While foliar chemistry was quite variable, fumigation generally decreased sugars and proteins, and increased amino acids and phenolics in A. curassavica. Effects were similar in A. syriaca except that sugars were generally increased while amino acids were usually not affected. On A. curassavica, 3rd instar larvae preferred ozone-treated leaves while 4th instars showed no preference; conversely, on A. syriaca, 3rd instars showed no preference while 4th instars preferred control leaves. Relative growth rate and relative consumption rate of 5th instars were greater on fumigated plants of both species, but other nutritional indices were unaffected. Larvae developed more rapidly on intact fumigated plants of both species than on the respective controls. The results suggest that enhanced feeding stimulation may be the primary cause of the altered behavior and performance on ozone-fumigated plants.     

Flora and Vegetation of Tasiilaq,Formerly Angmagssalik,Southeast Greenland: A Comparison of Data Between Around 1900 and 2007

The changes in the vascular plant flora of Tasiilaq, low arctic Southeast Greenland, between around 1900 and 2007 were studied by comparing the data from historical literature with those of the field observations performed between the late 1960s and 2007. Since 1900, the percentage of widely distributed arctic species distinctly decreased, whereas that of the low arctic species somewhat increased, and boreal species hardly increased. Vegetation monitoring revealed minor changes and showed that several thermophilous and xerophilous species increased between 1968/1969 and 2007, whereas some hygrophilous species decreased. Repeated vegetation mapping of a shallow pond revealed conspicuous changes suggesting increased evaporation/precipitation ratios associated with environmental warming up and decreasing snow accumulation in winter, in line with results of previous investigations. In spite of climate warming, expansion of the town and increasing human impact, flora and vegetation on the whole appeared rather stable during the last 40 years without invading species or introductions.     

Preliminary field study of hepatic porphyrin profiles of Astyanax fasciatus (Teleostei, Characiformes) to define anthropogenic pollution

The implementation of eco-toxicological assessment in South America is presently limited due to significant scientific information gaps concerning native species and their potential use as biomarkers. Recently, a common southern hemisphere fish species, Astyanax fasciatus, has been pointed out as a potential bio-indicator to anthropogenic pollution. This is a small, abundant, Neotropical characid, which is widely distributed from Central America south, to the Rio de la Plata Basin of western Uruguay. Our study found a statistically significant increase of coproporphyrin, uroporphyrin and protoporphyrin concentrations in hepatic tissues of A. fasciatus collected from a stream segment with high anthropogenic disturbance (due mainly to agricultural derivatives and motor vehicle transportation activities). Although the area studied showed differences in up and downstream limno-chemical parameters, these differences were not related to the increase of hepatic porphyrin concentrations. Based on the results of our study, we conclude that A. fasciatus is a good bio-indicator of exposure to environmental contaminants, and we propose that this abundant fish species be considered as a sentinel organism for monitoring potential disturbances to freshwater ecosystems.     

Impacts of a mosquito selective pesticide, Bti, on the macroinvertebrates of a subtropical stream in Hong Kong

To test the hypothesis that Bti was specific to mosquito larvae, the granular form of Bti was tested on commonly found Hong Kong species from four naturally occuring aquatic insect orders and one species of decapod crustacean (Neocardina serra). Because data on Bti impacts on species in tropical and subtropical countries is relatively rare, the present study was conducted in Hong Kong's New Territories. Using static acute toxicity bioassays, all mosquito larvae exposed to Bti at the recommended dosage were dead except for some dark pigmented fourth instar individuals that had stopped feeding prior to emergence and as a result, did not ingest the Bti toxin. The only non-target species killed by the Bti were some chironomid species. In 1998 Bti inoculated pools along the Tai Tan River in the New Territories of Hong Kong had significantly fewer chironomids and mosquito larvae than control pools. By January, 1999, these same Bti inoculated pools still had no mosquito larvae in them, however, chironomids were no longer significantly rarer when compared to the control ponds. Thus, it would appear, that during the 1998-99 study in which Bti was added to the study sites at weekly intervals, Bti resistant chironomid species replaced Bti sensitive species in the Bti inoculated pools.     

An adaptive reduction algorithm for efficient chemical calculations in global atmospheric chemistry models

We present a computationally efficient adaptive method for calculating the time evolution of the concentrations of chemical species in global 3-D models of atmospheric chemistry. Our strategy consists of partitioning the computational domain into fast and slow regions for each chemical species at every time step. In each grid box, we group the fast species and solve for their concentration in a coupled fashion. Concentrations of the slow species are calculated using a simple semi-implicit formula. Separation of species between fast and slow is done on the fly based on their local production and loss rates. This allows for example to exclude short-lived volatile organic compounds (VOCs) and their oxidation products from chemical calculations in the remote troposphere where their concentrations are negligible, letting the simulation determine the exclusion domain and allowing species to drop out individually from the coupled chemical calculation as their production/loss rates decline. We applied our method to a 1-year simulation of global tropospheric ozone-NO_x-VOC-aerosol chemistry using the GEOS-Chem model. Results show a 50% improvement in computational performance for the chemical solver, with no significant added error.     

Do herbicide treatments reduce the sensitivity of mosquito larvae to insecticides?

Invasive mosquitoes are economic and sanitary concerns especially in Europe and America. Most work has emphasized the role of resistance [Berrada, S., Fournier, D., Cuany, A., Nguyen, T.X., 1994. Identification of resistance mechanisms in a selected laboratory strain of Cacopsylla pyri (Homoptera: Psyllidae): altered acetylcholinesterases and detoxifying oxidases. Pesticide Biochemistry and Physiology 48, 41-47; Hemingway, J., Hawkes, N.J., McCarroll, L., Ranson, H., 2004. The molecular basis of insecticide resistance in mosquitoes. Insect Biochemistry and Molecular Biology 34, 653-665] to insecticides. Compounds acting on larval sensitivity to insecticides are not well studied and their action remains poorly understood. Among several residual chemicals in ecosystems, particularly in wetlands, we identified a possible interaction of an herbicide on larval resistance to an insecticide. Our work contributes to the global control of mosquito populations by identifying possible pathways of resistance to insecticides of these vectors. Resistance or tolerance to insecticide treatments might contribute to successful invasion by mosquitoes. Here we report an ecotoxicological approach to test the hypothesis of an indirect effect of atrazine on mortality of an invasive vector. A brief contact (48h) between Aedes aegypti mosquito larvae and atrazine led to a modification of larval sensitivity to an insecticide: using atrazine as an inducer led to a decrease in the mortality of larvae treated with Bacillus thuringiensis var. israelensis (Bti).     

Assimilation efficiencies of Cd and Zn in the common carp (Cyprinus carpio): effects of metal concentration, temperature and prey type

The impact of several factors on the assimilation efficiency (AE) of Cd and Zn from food in the common carp (Cyprinus carpio) was studied. Tested prey species were midge larvae (Chironomus riparius), zebra mussels (Dreissena polymorpha) and oligochaetes (Tubifex tubifex). The Cd load of the larvae did not affect the Cd AE in the carp. The Zn AE however, was negatively related to the Zn load of the prey. Food quantity and starvation of the carp did not significantly affect the Cd AE. For Zn, a significant decrease in AE was found when carp were fed ad libitum. Decreasing the temperature from 25 degrees C to 15 degrees C did not influence the Cd AE, while for Zn a significant decrease of the AE was measured. Carp assimilated Cd from both zebra mussels and oligochaetes with a significantly lower efficiency in comparison to the midge larvae, although Zn AEs was prey independent.     

Metal bioaccumulation and metallothionein concentrations in larvae of Crassostrea gigas

Larval stages of bivalve molluscs are highly sensitive to pollutants. Oysters from a hatchery from Normandy (English Channel) were induced to spawn, and fertilized eggs were exposed to copper or cadmium for 24 h. Metal accumulation (from 0.125 to 5 microg Cu L(-1) and from 25 to 200 microg Cd L(-1)) and MT concentrations were measured in larvae. Compared to controls, larvae accumulated copper and cadmium with an increase in MT concentrations particularly with cadmium (i.e. 130.96 ng Cu (mg protein)(-1) and 12.69 microg MT (mg protein)(-1) at 1 microg Cu L(-1) versus 23.19 ng Cu (mg protein)(-1) and 8.92 microg MT (mg protein)(-1) in control larvae; 334.3 ng Cd (mg protein)(-1) and 11.70 microg MT (mg protein)(-1) at 200 microg Cd L(-1) versus 0.87 ng Cd (mg protein)(-1) and 4.60 microg MT (mg protein)(-1) in control larvae). Larvae were also obtained from oysters of a clean area (Arcachon Bay) and a polluted zone (Bidassoa estuary) and exposed to copper in the laboratory, their MT concentration was measured as well as biomarkers of oxidative stress. Biomarker responses and sensitivity to copper for the larvae from Arcachon oysters were higher than for those from Bidassoa.     

Responses to ozone of insects feeding on a crop and a weed species

The influence of ozone on insect herbivore growth and population development was investigated. Fumigation of both pea (Pisum sativum L.) and dock (Rumex obtusifolius L.) at a range of O(3) concentrations between 21-206 nl litre(-1) produced changes in mean relative growth rates of the aphids Acyrthosiphon pisum Harris and Aphis rumicis L. of between 24 and -6% relative to controls. However, there was no evidence of a dose-related response to O(3) fumigation and no clear differences in aphid response when fumigated with the plant on prefumigated or previously unfumigated plant material. It is suggested that this may, in part, be due to the presence of NO contamination during O(3) fumigation. However, the MRGR of dock aphids was found to be greater on new compared to old leaves as well as the increase on the new growth and decrease on the old growth of fumigated plants relative to unfumigated controls. The size of egg batches of the chrysomelid beetle Gastrophysa viridula Degeer were found to be larger, survival and productivity of larvae was higher, and the food consumption lower on R. obtusifolius fumigated with 70 nl litre(-1) O(3) compared with unfumigated controls. This meant that these beetle larvae consumed less leaf area per mg of production on fumigated leaves probably because of their better nutritional quality and/or reduced leaf defences. However, the rate of development of larvae was similar on fumigated and control plants.