Toxicity of fipronil and its enantiomers to marine and freshwater non-targets

Fipronil is a phenylpyrazole insecticide used in agricultural and domestic settings for controlling various insect pests in crops, lawns, and residential structures. Fipronil is chiral; however, it is released into the environment as a racemic mixture of two enantiomers. In this study, the acute toxicity of the (S,+) and (R,-) enantiomers and the racemic mixture of fipronil were assessed using Simulium vittatum IS-7 (black fly), Xenopus laevis (African clawed frog), Procambarus clarkii (crayfish), Palaemonetes pugio (grass shrimp), Mercenaria mercenaria (hardshell clam), and Dunaliella tertiolecta (phytoplankton). Results showed that S. vittatum IS-7 was the most sensitive freshwater species to the racemic mixture of fipronil (LC50 = 0.65 microg/L) while P. pugio was the most sensitive marine species (LC50 = 0.32 microg/L). Procambarus clarkii were significantly more sensitive to the (S,+) enantiomer while larval P. pugio were significantly more sensitive to the (R,-) enantiomer. Enantioselective toxicity was not observed in the other organisms tested. Increased mortality and minimal recovery was observed in all species tested for recovery from fipronil exposure. These results indicate that the most toxic isomer of fipronil is organism-specific and that enantioselective toxicity may be more common in crustaceans than in other aquatic organisms.     

Volatile emissions from the flea beetle Altica litigata (Coleoptera: Chrysomelidae) associated with invasive Ludwigia hexapetala

The flea beetle Altica litigata (Chrysomelidae) is an insect herbivore to plants within the families Lythraceae and Onagraceae, including ornamentals such as crape myrtle, Lagerstroemia spp. This insect is important both as a pest species and as a naturally occurring biological control agent due to its aggregate feeding behavior, which typically results in severe defoliation of the host plant. Despite the negative economic impact to ornamentals and contrary benefits as a biological control agent, there are few reports on the semiochemical communication of this family of insects. Uruguayan primrose-willow (Ludwigia hexapetala) is an invasive aquatic weed in California and serves as a host to A. litigata. To better characterize this association, the volatile emissions of A. litigata were collected while the flea beetles were: in containers by themselves, in containers with L. hexapetala leaves, in situ on L. hexapetala leaves in a growth chamber, and in situ on L. hexapetala leaves in the field. For comparison, the volatile emissions of A. litigata associated with two subspecies of creeping water primrose (L. peploides) were also evaluated. Two himachalene-type sesquiterpenes, showing the same carbon skeleton as compounds previously reported from Aphthona flava and Epitrix fuscula, were detected as volatiles from A. litigata.     

Intraspecific trait variants determine the nature of interspecific interactions in a habitat-forming species

Although the study of ecological interactions often takes into account functional variation between species, intraspecific variation is commonly ignored. Here, we investigate the importance of an intraspecific polymorphism in shaping interspecific interactions in a habitat-building species. Colonies of the social spider Anelosimus studiosus provide habitat for dozens of arthropod species, and colony members exhibit markedly polymorphic behavioral temperaments (BT): "aggressive" or "docile." We manipulated the phenotypic compositions of colonies (100% aggressive, 50% aggressive and 50% docile, 100% docile) and measured the nature and magnitude of interactions between A. studiosus and two heterospecific web associates, Larinioides cornutus and Agelenopsis emertoni. We found that BT composition significantly affected the outcome of interspecific interactions, changing the relationship between A. studiosus and its web associates from an ammensalism (where A. studiosus experiences reduced fecundity and survival) to a commensalism or mutualism. Our study successfully illustrates the potential of BTs to impact whole community dynamics, and conversely, for community structure to influence the maintenance of BTs.     

Decomposing patterns of emission intensity in the EU and China: how much does trade matter?

We use data from the World Input-Output Database to examine channels through which CO₂ emissions are embodied within, and imported into, the European production in 2005 and in 2009. We use an input–output price model to simulate the effect that a rise in the price of emissions trading system (ETS) allowances would have on the final price of goods. We find a reduction in emission intensity, which was greatest in those sectors regulated under ETS. Finally we examine the trade between China and the EU to study possible increases in carbon leakage. Results show that emissions embodied in imported intermediate goods have increased in all sectors.     

Climate change: an amplifier of existing health risks in developing countries

Global warming is perceived as one of the biggest global health risks of the twenty-first century and a threat to the achievement of sustainable (economic) development; especially in developing countries, climate change is believed to further exacerbate existing vulnerability to disease and food security risks, because their populations are, for example, more reliant on agriculture and more vulnerable to droughts and have a lower adaptive capacity. Furthermore, the health-related impacts of climate change are threatening to undo decades of development policies. The interactions between climate and non-climate factors are of vital importance in shaping human vulnerability to global warming. Climate change cannot be seen as ‘a stand-alone risk factor,’ but rather as an amplifier of existing health and food security risks and an additional strain on institutional infrastructures. In order to avoid a multiplication of health risks in the developing world, there is a need to better understand the multifaceted and complex linkages involved. This is further illustrated for two important climate change–induced health risks, namely malnutrition and malaria. As the amplification of existing and emerging health risks in the developing world might become the greatest tragedy of climate change, adaptation ranks high on developing countries’ agendas. Of particular importance are the discussions about the ‘Green Climate Fund,’ which aims to administer billions of dollars for mitigation and adaptation. Of course, making funds for adaptation available is an important first step, but we also need to ask ourselves the question how such adaptation policies and projects should take shape. This paper demonstrates that an adequate response to climate change health risks should take a systems approach toward adaptation, acknowledging the importance of the local context of the most vulnerable.