Exchange of hosts: can agaonid fig wasps reproduce successfully in the figs of non-host <Emphasis Type="BoldItalic">Ficus</Emphasis>?

In the obligate mutualism between figs (Ficus) and their specific pollinators (Chalcidoidea, Agaonidae), each species of fig wasp typically reproduces in figs of a single host species. Host specificity is maintained largely because pollinators are attracted to tree-specific volatiles released from their host figs, but whether the wasps can reproduce if they enter figs of non-host species is unclear. We investigated the reproductive success of Ceratosolen emarginatus (associated with Ficus auriculata) and Ceratosolen sp. (associated with F. hainanensis) in atypical hosts by experimentally introducing foundresses into host and non-host figs. F. auriculata figs entered by Ceratosolen sp. were more likely to abort than if entered by C. emarginatus, but abortion of F. hainanensis figs was not affected by pollinator species. Single C. emarginatus foundresses produced more but smaller offspring in F. hainanensis than in their normal host. Conversely Ceratosolen sp. produced fewer but larger offspring in F. auriculata than in their normal host, probably as a result of having longer to develop. Mean style length differences, relative to the lengths of the wasps’ ovipositors, may have dictated the number of offspring produced, with oviposition made easier by the shorter styles in F. hainanensis figs. Our results imply that, in addition to morphological constraints and tree-specific volatiles, reduced reproductive success in atypical hosts can be another factor maintaining host specificity, but for other species only behavioural changes are required for host switching to occur.     

Soil moisture determines the effectiveness of two urease inhibitors to decrease N<Subscript>2</Subscript>O emission

Among the mitigation strategies to prevent nitrogen (N) losses from ureic fertilizers, urease inhibitors (UIs) have been demonstrated to promote high N use efficiency by reducing ammonia (NH₃) volatilization. In the last few years, some field experiments have also shown its effectiveness in reducing nitrous oxide (N₂O) losses from fertilized soils under conditions of low soil moisture. An incubation experiment was carried out with the aim of assessing the main biotic mechanisms behind N₂O emissions once that the UIs N-(n-butyl) thiophosphoric triamid (NBPT) and phenil phosphorodiamidate (PPDA) were applied with Urea (U) under different soil moisture conditions (40, 60 and 80 % water-filled pore space, WFPS). In the same study we tried to analyze to what extent soil WFPS regulates the effect of these inhibitors on N₂O emissions. The use of PPDA in our study allowed us to compare the effect of NBPT with that of another commercially available urease inhibitor, aiming to see if the results were inhibitor-specific or not. Based on the results from this experiment, a WFPS (i.e. 60 %) was chosen for a second study (i.e. mesocosm experiment) aiming to assess the efficiency of the UIs to indirectly affect N₂O emissions through influencing the pool of soil mineral N. The N₂O emissions at 40 % WFPS were almost negligible, being significantly lower from all fertilized treatments than that produced at 60 and 80 % WFPS. When compared to U alone, NBPT+U reduced the N₂O emissions at 60 % WFPS but had no effect at 80 % WFPS. The application of PPDA significantly increased the emissions with respect to U at 80 % WFPS whereas no significant effect was found at 60 %. At 80 % WFPS, denitrification was the main source of N₂O emissions for all treatments. In the mesocosm study, the application of NBPT+U was an effective strategy to reduce N₂O emissions (75 % reduction compared to U alone), due to a lower soil ammonium (NH₄ ⁺) content induced by the inhibitor. These results suggest that adequate management of the UI NBPT could provide, under certain soil conditions, an opportunity for mitigation of N₂O emissions from fertilized soils.     

Carbon mitigation potential of Indian steel industry

Steel dominates the global metal production accounting for 5 % of increase in Earth’s atmospheric carbon dioxide (CO₂). Today, India is the 4th largest producer of crude steel in the world. The sector contributes around 3 % to the country’s gross domestic product (GDP) but adds 6.2 % to the national greenhouse gas (GHG) load. It accounts for 28.4% of the entire industry sector emissions, which are 23.9% of the country’s total emissions. Being a developing country, India is not obliged to cut its emissions under the Kyoto Protocol to the United Nations Framework Convention on Climate Change (FCCC), but gave voluntary commitment to reduce the emission intensity of its GDP by 20–25 % from the 2005 level by 2020. This paper attempts to find out if the Indian steel sector can help the country in fulfilling this commitment. The sector reduced its CO₂ emissions per ton of steel produced by 58% from 1994 to 2007. The study generates six scenarios for future projections which show that the sector can reduce its emission intensity by 12.5 % to 63 %. But going by the conservative estimates, the sector can reduce emission intensity by 30 % to 53 %. However, actual emissions will go up significantly in every case.     

Using activated biochar for greenhouse gas mitigation and industrial water treatment

This study explored the feasibility of using residual biomass to both mitigate greenhouse gas (GHG) emissions and remediate water contaminated by hydrocarbons. Using produced (process-affected) water from Canada’s oil sands operations as a case study, activated biochar (ACB) was found to have a higher affinity to organics than activated coal and removed 75 % of total organic carbon (TOC) from produced water in steam-assisted gravity drainage (SAGD) operations or 90 % of the TOC from synthetic tailings (ST) water sample. Up to 6 Tg dry biomass year^?1 would be required to treat the waters associated with the 93?×?10⁶-m³ of bitumen recovered per year. Landfilling the spent ACB and flaring any biogas produced were estimated to provide a greater GHG benefit than the combustion of the biochar + organics for heat to offset natural gas demand. Net costs for the ACB were about 13.84?$?m^?3 bitumen for SAGD operations and 1.76?$?m^?3 bitumen for mining operations. The values for mining operations justify further work to create a value chain that will integrate bioprocesses into the fossil fuel industry.     

Geographic variation in resource allocation to the abdomen in geometrid moths

A resource allocation trade-off is expected when resources from a common pool are allocated to two or more traits. In holometabolous insects, resource allocation to different functions during metamorphosis relies completely on larval-derived resources. At adult eclosion, resource allocation to the abdomen at the expense of other body parts can be seen as a rough estimate of resource allocation to reproduction. Theory suggests geographic variation in resource allocation to the abdomen, but there are currently no empirical data on it. We measured resource allocation to the abdomen at adult eclosion in four geometrid moths along a latitudinal gradient. Resource (total dry material, carbon, nitrogen) allocation to the abdomen showed positive allometry with body size. We found geographic variation in resource allocation to the abdomen in each species, and this variation was independent of allometry in three species. Geographic variation in resource allocation to the abdomen was complex. Resource allocation to the abdomen was relatively high in partially bivoltine populations in two species, which fits theoretical predictions, but the overall support for theory is weak. This study indicates that the geographic variation in resource allocation to the abdomen is not an allometric consequence of geographic variation in resource acquisition (i.e., body size). Thus, there is a component of resource allocation that can evolve independently of resource acquisition. Our results also suggest that there may be intraspecific variation in the degree of capital versus income breeding.     

The oral cone of Anomalocaris is not a classic ‘‘peytoia’’

The Cambro-Ordovician anomalocaridids are large ecdysozoans commonly regarded as ancestors of the arthropods and apex predators. Predation is indicated partly by the presence of an unusual “peytoia”-type oral cone, which is a tetraradial outer ring of 32 plates, four of which are enlarged and in perpendicular arrangement. This oral cone morphology was considered a highly consistent and defining characteristic of well-known Burgess Shale taxa. It is here shown that Anomalocaris has a different oral cone, with only three large plates and a variable number of smaller and medium plates. Its functional morphology suggests that suction, rather than biting, was used for food ingestion, and that anomalocaridids in general employed a range of different scavenging and predatory feeding strategies. Removing anomalocaridids from the position of highly specialized trilobite predators forces a reconsideration of the ecological structure of the earliest marine animal communities in the Cambrian.     

RNA interference: from an ancient mechanism to a state of the art therapeutic application?

Now that the sequencing of many genomes has been completed, the basic challenges are finding the genes and predicting their functions. Up until now, a large information gap has existed between the knowledge of genome sequence and our knowledge of protein function. The assessment of gene function may be performed using the tools of reverse genetics, including knock-out mice, antisense oligomers, aptamers, and ribozymes. These approaches have been superseded by RNA interference (RNAi), which exhibits much more potency for the investigation of protein function than the techniques listed above. As already known some years ago, RNAi is based on an ancient anti-viral defense mechanism in lower eukaryotes. It is induced by double-stranded RNA and its processing to 21–23 nt small interfering RNAs (siRNAs), which cause the degradation of homologous endogenous mRNA. The way RNAi works has still to be determined, but it already serves as a first-choice approach to generate loss-of-function phenotypes among a broad variety of eukaryotic species, such as nematodes, flies, plants, fungi and mammals. RNAi also represents an extremely powerful tool, becoming a therapeutic approach to curing infectious diseases originated by viral or parasitic invasion. In this review we present the current view of how RNAi works in different eukaryotic species and its high potential for functional genomics and in rational drug design.     

The effect of metapleural gland secretion on the growth of a mutualistic bacterium on the cuticle of leaf-cutting ants

In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics controlling a microfungal parasite of their fungus gardens. Interaction between this bacterium and gland secretion therefore seems unavoidable. We document the typical development of bacterial growth on the cuticle of young major workers, show that growth starts a few days after eclosion, and that the maximal cover is reached after 2–3 weeks and gradually declines when workers mature. Experimental closure of the metapleural glands had no effect on the initial exponential growth phase of the bacterium, but significantly reduced the cover during the decline phase. The age-dependent abundance of the bacterium and its partial dependence on metapleural gland secretion support the hypothesis that the abundance of this mutualist is actively regulated.     

Assessment of global industrial-age anthropogenic arsenic contamination

Arsenic, a carcinogenic trace element, threatens not only the health of millions of humans and other living organisms, but also global sustainability. We present here, for the first time, the global industrial-age cumulative anthropogenic arsenic production and its potential accumulation and risks in the environment. In 2000, the world cumulative industrial-age anthropogenic arsenic production was 4.53 million tonnes. The world-wide coal and petroleum industries accounted for 46% of global annual gross arsenic production, and their overall contribution to industrial-age gross arsenic production was 27% in 2000. Global industrial-age anthropogenic As sources (as As cumulative production) follow the order: As mining production >As generated from coal >As generated from petroleum. The potential industrial-age anthropogenic arsenic input in world arable surface in 2000 was 2.18 mg arsenic kg^–1, which is 1.2 times that in the lithosphere. The development of substitute materials for arsenic applications in the agricultural and forestry industries and controls of arsenic emissions from the coal industry may be possible strategies to significantly decrease arsenic pollution sources and dissipation rates into the environment.