Genetic variation in defense chemistry in wild cabbages affects herbivores and their endoparasitoids

Populations of wild Brassica oleracea L. grow naturally along the Atlantic coastlines of the United Kingdom and France. Over a very small spatial scale (i.e., <15 km) these populations differ in the expression of the defensive compounds, glucosinolates (GS). Thus far, very few studies have examined interactions between genetically distinct populations of a wild plant species and associated consumers in a multitrophic framework. Here, we compared the development of a specialist (Pieris rapae) and a generalist (Mamestra brassicae) insect herbivore and their endoparasitoids (Cotesia rubecula and Microplitis mediator, respectively) on three wild populations and one cultivar of B. oleracea under controlled greenhouse conditions. Herbivore performance was differentially affected by the plant population on which they were reared. Plant population influenced only development time and pupal mass in P. rapae, whereas plant population also had a dramatic effect on survival of M. brassicae. Prolonged development time in P. rapae corresponded with high levels of the indole GS, neoglucobrassicin, whereas reduced survival in M. brassicae coincided with high levels of the aliphatic GS, gluconapin and sinigrin. The difference between the two species can be explained by the fact that the specialist P. rapae is adapted to feed on plants containing GS and has evolved an effective detoxification system against aliphatic GS. The different B. oleracea populations also affected development of the endoparasitoids. Differences in food-plant quality for the hosts were reflected in adult size in C. rubecula and survival in M. mediator, and further showed that parasitoid performance is also affected by herbivore diet.     

Ecotoxicological assessment of doxycycline in soil

Doxycycline has been used in continually increasing quantities for mass treatment of food animals because of its greater bioavailability relative to older tetracyclines. The study presented in this paper was undertaken to investigate the degradation rate of the tetracycline derivative in manure-amended soil. In the present experiment, following composting, the doxycycline-contaminated manure was applied to agricultural land, and a field study was performed to investigate the degradation rate of doxycycline in soil. By the end of the 20-week sampling period, about 20 %, 33 % and 18 % of the initial doxycycline concentrations could be measured in soil samples taken at three different soil depths. The calculated half-life of doxycycline in the soil was 66.5, 76.3 and 59.4 days at depths of 0 cm, 25 cm and 50 cm, respectively. The potential effect of doxycycline on soil microbial activity was demonstrated by the nitrogen transformation test performed in compliance with the Organisation for Economic Co-operation and Development (OECD) Guideline No. 216. On day 28, the following nitrate concentrations of the control soil sample were found in the soil samples treated with different amounts of doxycycline: 76.9 %, 53.0 %, 65.6 %, 59.7 % and 77.1 %.     

Evaluation of caged freshwater mussels as an alternative method for environmental effects monitoring (EEM) studies

On three occasions between 1998 and 2000, freshwater mussels were collected by divers in Lake Memphremagog during the spring and transplanted to various locations in the St-Fran?ois River (Quebec, Canada). Mussel growth was monitored by comparing total weight and length at the beginning and end of the exposure period. In 1998, mussels were caged for 60 days at 10 stations, including locations receiving treated effluents from three pulp and paper mills. Overall, there was an apparent trend of increased mussel growth from upstream to downstream along the river. However, mussels caged downstream from the effluent discharge of a bleached kraft pulp and paper mill grew more slowly than those caged immediately upstream in the river. In 1999 and 2000, we further investigated the situation in the vicinity of this bleached kraft mill. The measurements again indicated that growth of mussels in the effluent plume from this mill was reduced in comparison to sites upstream. Overall, in terms of growth, the caged mussels responded both positively and negatively to different environmental conditions. Compared with other monitoring approaches used at these sites during the same period, the caged mussel experiment results were consistent with the trends observed with the benthic invertebrate survey but not with the trends observed for fish.     

Tail loss and thermoregulation in the common lizard<Emphasis Type="Italic"> Zootoca vivipara</Emphasis>

Tail autotomy in lizards is an adaptive strategy that has evolved to reduce the risk of predation. Since tail loss reduces body mass and moving ability—which in turn are expected to influence thermal balance—there is potential for a trade-off between tail autotomy and thermoregulation. To test this hypothesis, we studied a common lizard (Zootoca vivipara) population at high latitude, inhabiting a high-cost thermal environment. Z. vivipara is a small, non-territorial lizard known as a very accurate thermoregulator. We made two predictions: (1) the reduced body weight due to tail loss results in faster heating rate (a benefit), and (2) the reduction in locomotor ability after tail loss induces a shift to the use of thermally poorer microhabitats (a cost), thus decreasing the field body temperatures of active lizards. We did not find any effect of tail loss on heating rate in laboratory experiments conducted under different thermal conditions. Likewise, no significant relationship between tail condition and field body temperatures, or between tail condition and thermal microhabitat use, were detected. Thus, our results suggest that tail autotomy does not influence the accuracy of thermoregulation in small-bodied lizards.Electronic Supplementary Material  Supplementary material is available in the online version of this article at     

Ecotoxicological assessment of doxycycline in soil

Doxycycline has been used in continually increasing quantities for mass treatment of food animals because of its greater bioavailability relative to older tetracyclines. The study presented in this paper was undertaken to investigate the degradation rate of the tetracycline derivative in manure-amended soil. In the present experiment, following composting, the doxycycline-contaminated manure was applied to agricultural land, and a field study was performed to investigate the degradation rate of doxycycline in soil. By the end of the 20-week sampling period, about 20 %, 33 % and 18 % of the initial doxycycline concentrations could be measured in soil samples taken at three different soil depths. The calculated half-life of doxycycline in the soil was 66.5, 76.3 and 59.4 days at depths of 0 cm, 25 cm and 50 cm, respectively. The potential effect of doxycycline on soil microbial activity was demonstrated by the nitrogen transformation test performed in compliance with the Organisation for Economic Co-operation and Development (OECD) Guideline No. 216. On day 28, the following nitrate concentrations of the control soil sample were found in the soil samples treated with different amounts of doxycycline: 76.9 %, 53.0 %, 65.6 %, 59.7 % and 77.1 %.     

Analysis of conservative tracer measurement results inside a planted horizontal subsurface flow constructed wetland filled with coarse gravel using Frechet distribution

Environmental Science and Pollution Research - We worked out a method in Maple environment to help understand the difficult transport processes in horizontal subsurface flow constructed wetlands...     

Can a unique appearance of e-bikes,coupled with information on their characteristics,influence drivers’ gap acceptance?

Abstract

Objective: Car drivers tend to underestimate the speed of e-bikes and accept smaller gaps for crossing in front of them compared to conventional bicycles. As an explanation, it has been suggested that car drivers rely on their previous experience with conventional bicycles, which tells them that those mostly travel at low speeds. E-bikes, which look just like regular bicycles, do not conform to this expectation, resulting in potentially dangerous interactions. Based on this assumption, researchers have suggested to increase other road users’ awareness of e-bikes’ higher speeds by giving them a distinct appearance. The goal of our experiment was to investigate the effects of such a unique appearance, aided by clear instructions about the higher speeds of e-bikes, on gap acceptance.

Method: In order to investigate the effect of appearance independent of the effect of bicycle type, we used video sequences of conventional bicycles and e-bikes approaching at different levels of speed. The riders (regardless of what type of bike they were actually riding) either wore an orange helmet as an indicator for an e-bike, or a gray helmet indicating a conventional bicycle. Fifty participants were asked to indicate the smallest acceptable gap for a left turn in front of the cyclist or e-bike rider.

Results: The results showed significantly smaller acceptable gaps when confronted with the gray helmet (signal for bicycle) compared to the orange helmet (signal for e-bike), whereas there was no difference between the actual bicycle types.

Conclusions: Overall, the results indicate that informing about e-bikes characteristics in combination with a unique appearance can lead to a more cautious behavior among car drivers.     

Biological activity and environmental impact of anionic surfactants

The newest results concerning the biological activity and environmental fate of anionic surfactants are collected and critically evaluated. The chemical and physicochemical parameters related to the biological activity and the field of application are briefly discussed. Examples on the effect of anionic surfactants on the cell membranes, on the activity of enzymes, on the binding to various proteins and to other cell components and on their human toxicity are presented and the possible mode of action is elucidated. The sources of environmental pollution caused by anionic surfactants are listed and the methods developed for their removal from liquid, semiliquid and solid matrices are collected. Both the beneficial and adversary effects of anionic surfactants on the environment are reported and critically discussed. It was concluded that the role of anionic surfactants in the environment is ambiguous: they can cause serous environmental pollution with toxic effect on living organisms; otherwise, they can promote the decomposition and/or removal of other inorganic and organic pollutants from the environment. The relationship between their chemical structure, physicochemical parameters, biological activity and environmental impact is notwell understood. A considerable number of data are needed for the development of new anionic surfactants and for the successful application of the existing ones to reduce the adversary and to promote beneficial effects.