Thermal dependence of Daphnia life history reveals asymmetries between key vital rates.

Temperature variation affects virtually every aspect of ectotherms' ecological performance, such as their foraging rate, reproduction, and survival. Although these changes influence what happens at higher levels of organizations, such as populations and communities, qualitative changes in dynamics usually require some degree of asymmetry between key vital rates, i.e. that different vital rates, such as growth, development, fecundity and mortality rates, respond differently to temperature. In order to identify possible asymmetries among vital rates and/or life stages, we characterized the thermal response of individuals a clone of Daphnia sinensis, drawn from a high-mountain environment in Taiwan, and examined the temperature dependence of growth, maturation, reproduction, and mortality rates, as well as fitness measures (r and R0) at eight temperatures. Daphnia sinensis was able to maintain reproductive success over a broad range of temperatures, much wider than the one experienced in its environment. However, negative effects of temperature were perceptible at temperatures much lower than the highest one at which they can achieve reproductive success. Adult mortality greatly increased for temperatures above 23 °C, and other vital rates started to decelerate, resulting in a large drop in lifetime reproductive success. This finding implies that D. sinensis may be able to persist over a wide range of temperatures, but also that it may become more sensitive to the detrimental effect of species interactions at increased temperatures. Different vital rates responded relatively similarly at low temperatures, but the degree of asymmetry among these rates was much more pronounced at higher temperatures. In particular, rates associated with adult performance decelerated more strongly than juveniles' rates. These findings indicate that elevated temperatures affect the balance between juvenile and adult performance, which is known to have a crucial role in Daphnia population dynamics. We discuss the implications of these results for the dynamics of structured populations.

Ozonized 2-hydroxypropyl-ß-cyclodextrins as novel materials with oxidative and bactericidal properties.

Ozonized (2-Hydroxypropyl)-ß-cyclodextrins (Oz-HPbCDs) were produced by direct gas/solid reaction between gaseous ozone (O3) and solid HPbCD. The solid materials obtained were first characterized using physical and chemical methods and compared to the initial HPbCD. The main process parameters of the synthesis were studied independently to assess their effect on the oxidizing power of Oz-HPbCDs. The ability of the Oz-HPbCDs to retain their oxidative properties over time was evaluated, at different storage temperatures, for a period of at least two months. Lastly, aqueous solutions of HPbCD and Oz-HPbCD at different concentrations were contacted with bacterial strains of Escherichia coli and Streptococcus uberis to see whether these materials might have bactericidal properties. Since normal bacterial growth was noted with HPbCD, the antimicrobial efficiency of Oz-HPbCDs was clearly demonstrated on these two types of bacteria.

Landscape forest impacts the potential activity time of an invasive lizard and its possibilities for range expansion in Taiwan under climate warming.

Climate warming may have an impact on invasive species and their ecological consequences. Invasive reptiles, which have temperature-dependent physiology, are expected to be greatly impacted by climate warming, though data supporting this is limited. We investigated the potential impact of a warmer climate on an invasive lizard, Eutropis multifasciata, in Taiwan. A mechanistic model, NicheMapR, was used to simulate the maximum activity time available at three elevations, with varying forest densities, under the current climate and a warmer scenario. The results show that climate warming will provide this species more time for activity in the currently occupied lowland region but not in the mountain areas, which are covered with dense forests. However, if the landscape becomes more open in mountain areas, it will become more suitable for this species and may enable an expansion upslope. Our results show that climate warming has a positive impact on this species, and that landscape's characteristics profoundly modulate its impact and the possibilities for elevational expansion in the future.

Thermal physiology explains the elevational range for a lizard, Eutropis longicaudata, in Taiwan.

1: The decrease of temperatures along an elevation gradient imposes physiological constraints on reptiles that ultimately determine their distribution ranges. Forest patterns are likely to interact with this process, but very few studies have examined their contribution in determining distribution limits. 2: We examined the role played by thermal physiology and forest cover in determining the elevational ranges of a lizard, Eutropis longicaudata. We integrated this species' thermal traits in simulating its maximum activity time under different conditions of forest cover and elevation using a NicheMapR model. In addition, we evaluated the influence of winter temperatures on the range limit by examining the simulated soil temperatures at the occurrence sites. 3: Laboratory experiments showed that E. longicaudata has a high preferred body temperature and low cold tolerance. The model predicts that maximum activity time decreases with elevation and forest cover. Although unforested areas may provide longer active time in all simulated elevations, mountain areas in Taiwan are heavily forested and are predicted to allow only a very short period of activity above 1000 m elevation. 4: All sightings were indeed located in areas below 1000 m elevation, in which the predicted average soil temperature is above 10 °C in January in cold years. 5: Our results show that reptile physiological response does respond strongly to the change of microclimate induced by forest cover and elevation. Overall, this suggests that forest cover is a major determinant of some reptiles' elevational range.

Temperature rise curtails activity period predicted for a winter-active forest lizard, Scincella formosensis, from subtropical areas in Taiwan.

1. Temperature rise due to climate change affects seasonal activity times, leading to a discordance of phenology among species and changing the strength of interaction between species. Understanding how temperature changes will affect the length of a species' activity period is essential in order to forecast its response to climate warming. 2. We investigated the thermal physiology and monthly activity of a skink from subtropical areas in Taiwan, Scincella formosensis. In addition, we predicted its response to climate warming and potential landscape vegetation changes using a mechanistic model, Niche MapperTM. We incorporated the animals' thermal traits and climatic data to simulate thermally suitable time for activity each month in two sites (open area, dense forest). 3. We found that this species restricts its activity to the cool months of the year, and that juveniles emerge in June. The thermally suitable period for activity is predicted to be longer in cool months than warm months. 4. Our model predicts that a 3 °C increase in temperature will curtail the thermally suitable time for activity in open areas in late spring and result in very minimal time for activity in the summer, even when dense forest is available. These results add to the growing body of literature indicating that a temperature rise will have a widespread impact on sub/tropical forest reptiles.

Enhancement of ciprofloxacin degradation in aqueous system by heterogeneous catalytic ozonation.

Fluoroquinolones are extensively used in medicine due to their antimicrobial activity. Their presence in water inhibits microorganism activity in conventional wastewater treatment plants. This study aims to evaluate the technical feasibility of applying heterogeneous catalytic ozonation to eliminate ciprofloxacin (CIP) as a representative of fluoroquinolone antibiotics normally present in municipal wastewater discharges. Experiments were conducted in a semi-batch stirred slurry reactor, using 0.7 L of 100 mg L-1 CIP aqueous solution, at pH 3 and 30 °C. Experimental results show that single ozonation can easily oxidise CIP molecules (68%) within the first 5 min, leading to the generation of refractory oxidation by-products. However, when heterogeneous catalytic ozonation is applied using iron oxide supported on MFI synthetic zeolite, total degradation of CIP is observed at 5 min and a higher mineralisation rate is obtained. A novel sequential process is developed for CIP mineralisation. In a first step, a flash single ozonation is applied and CIP molecules are broken down. Then, a catalytic ozonation step is conducted by adding the Fe/MFI catalyst into the reactor. As a result of catalyst addition, 44% of Total Organic Carbon (TOC) is eliminated within the first 15 min, compared to single ozonation where only 13% of TOC removal is reached in the same time. The application of this sequential process to a real wastewater effluent spiked with CIP leads to 52% of TOC removal.

Ozone Quantification by Selected Ion Flow Tube Mass Spectrometry: Influence of Humidity and Manufacturing Gas of Ozone Generator.

The quantification of ozone by SIFT-MS was investigated in conditions suitable with an industrial emission context (high ozone demand, dry air/oxygen as the manufacturing gas of the ozone generator, and high humidity levels beyond saturation at room conditions). Ozone reacts with four negative precursor ions available in the SIFT-MS device (NO2-, O2-, HO-, and O-), each precursor ion having its specific domain of linearity. For a high ozone concentration range, only NO2- and O2- have resulted in a linear behavior (between 1 and 100 ppmv of O3 for NO2-, between 1 and 50 ppmv of O3 for O2-). No water interference was identified during ozone measurements by SIFT-MS using NO2- and O2- precursor ions, even with extreme humidity levels. The presence of nitrogen oxide contaminants (due to the use of dry air as the manufacturing gas of the ozone generator) affected the ozone quantification by SIFT-MS. It is critical for NO2- precursor ions, whose rate constant varied as a function of NO2 concentrations. With O2- precursor ion, ozone was successfully measured in the presence of nitrogen oxides; however, the secondary chemistry must be taken into account.

Aldehydes gas ozonation monitoring: Interest of SIFT/MS versus GC/FID.

Two analytical techniques - online Gas Chromatography coupled with Flame Ionization Detector (often used method for VOCs monitoring) versus Selected Ion Flow Tube coupled with Mass Spectrometry (a more recent technique based on direct mass spectrometry) - were compared in association to an ozone-based gas treatment. Selecting aldehydes as the representative VOCs, their concentrations were monitored during ozonation experiments by both techniques in parallel. Contradictory results were obtained in the presence of ozone. Aldehydes were up to 90% removed due to a reaction with ozone according to GC/FID analysis, whereas with SIFT/MS, aldehydes concentration remained at the same level during the experiments regardless of the ozone presence. In addition, it was demonstrated that the apparent aldehydes removal was affected by GC injector temperature, varying from 90% (when it was at 250 °C) to 60% (at 100 °C). Meanwhile, even when the ozonation reactor was heated to 100 °C, no aldehydes conversion was evidenced by SIFT/MS, suggesting that the GC injector temperature was not the only interference-causing parameter. The ozone-aldehyde reaction is probably catalyzed by some material of GC injector and/or column. An ozone-GC interference was therefore confirmed, making unsuitable the use of GC/FID with silicone stationary phase to monitor aldehydes in presence of high concentrations of ozone (at least 50 ppmv). On the other hand, SIFT/MS was validated as a reliable technique, which can be employed in order to measure VOCs concentrations in ozonation processes.

Low cold tolerance of the invasive lizard Eutropis multifasciata constrains its potential elevation distribution in Taiwan.

1. The invasive many-lined sun skink, Eutropis multifasciata, is established in much of southern Taiwan and is spreading northward. We investigated whether winter temperatures constrain further dispersion of this skink by comparing its cold tolerance to the spatial distribution of winter temperatures in Taiwan. 2. We measured the 28-day survival rate of this species at 4 constant temperatures (10-16 °C in 2 °C increments) and its critical thermal minimum (CTmin), i.e., the body temperature at which the righting reflex is lost during the cooling process. For comparison with the spatial distribution of temperatures over Taiwan, we used the biophysical model Niche Mapper™ in order to simulate the soil temperatures, where lizards are inactive in the winter, during the coldest month of the year, January, under three climatic scenarios (average temperature, average-3 °C, average+3 °C). 3. Our results indicate that this species has low tolerance to cold. Combining cold tolerance data with soil temperature data suggests that its upper elevation limit could range from 1000 m to 1500 m, above which the weather is lethal and precludes overwintering. The locations of sightings of E. multifasciata are consistent with this prediction, with no known locations above 500 m elevation. 4. This study highlights that the winter climate is a major factor in determining population establishment and hence in limiting this species' range. Future studies would benefit from accounting for low winter temperatures and their potential influence on range limits of invasive species.

A host-feeding wasp shares several features of nitrogen management with blood-feeding mosquitoes.

Adult feeding on hosts is common among parasitic wasps. The ingested host fluid is rich in nutrients, especially proteins. A study on Eupelmus vuilleti (Hymenoptera: Eupelmidae), a host-feeding parasitoid of larvae of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae), showed that the carbohydrates (maybe lipids) but not proteins, gained from host feeding accounted for the increased egg production. Thus, host protein is probably utilized for general adult metabolism, allowing conservation of carbohydrate and/or lipid resources for direct allocation to oocytes. In that case, there should be increased N excretion by female parasitoids. To test this, we studied the dynamics of excretion in E. vuilleti with and without host exposure. The aim of this work was threefold: (i) to identify the major N-containing compounds in adult excreta, (ii) to assess whether protein consumption during host feeding increased the amount of N excreted, and (iii), if so, to compare the increase in N excreted with the amount taken in during a single host feeding. We found that uric acid is the predominant N-containing metabolite in excreta, although small quantities of urea and traces of allantoin were also found. A calculation of the N budget showed that the extra quantity of N excreted following a host meal corresponds to the quantity ingested, confirming that host-feeding in this species offers little or no net quantitative benefit in N allocation to oocytes, although the allocation of specific amino acids from host feeding cannot be discounted. Interestingly, host-feeding in parasitoids appears analogous to vertebrate blood-feeding in mosquitoes, both in terms of the N-containing compounds excreted and the offset of acquired N to metabolism, rather than to oocytes. Further comparative and detailed investigations of N excretion in insects living on other N-rich fluids might establish further metabolic commonalities.

The impact of development on patterns of nutrient limitation.

Development is often accompanied by major changes in an organism's functioning and in the way it interacts with its environment. We consider how developmental events such as allocation changes at maturity, ontogenetic diet shift or metamorphosis may affect the likelihood and nature of nutrient limitation and explore the consequences of these changes in nutrient limitation for individual life history and patterns of biomass production.To this purpose, we develop a general model for individual growth and reproduction that is based on the assumption that biomass production and metabolism require several nutrients and that individuals may require them in different proportion at different stages of their lives.We parameterize this model for Daphnia based on its physiological requirements for carbon (C) and phosphorus (P). Growth and reproduction have different nutrient requirements, and this affects the likelihood of C vs. P limitation of differently sized individuals. This translates into a size-dependent threshold elemental ratio (TER), with a difference of up to twofold between juveniles and adults, a difference comparable to measured interspecific differences.The main implications of these findings are that, at the population level, co-limitation of biomass production by several nutrients is likely to occur under a wide range of food qualities. In addition, different regimes of nutrient limitation strongly influence the relative difference in biomass production of differently sized individuals, which has been shown to be a major driver of population and community dynamics. Our results point to development as a key determinant of a population's response to food quality. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13101/suppinfo is available for this article.

Believability and Co-presence in Human-Virtual Character Interaction.

Subtle phenomena rooted in our body dynamics affect the reactive and evolutive parts of every human interaction. The authors' decision model allows for adaptive physical interactions between a human and a virtual agent. This article presents an evaluation of that model in terms of agent believability, the user's feeling of co-presence, and overall game experience. The results show that the model can generate adaptive body behavior for virtual agents that is comparable to a human's, but the user and agent roles in each scenario strongly impact the user's perception of the agent.

Increasing metabolic rate despite declining body weight in an adult parasitoid wasp.

Metabolic rate is a positive function of body weight, a rule valid for most organisms and the basis of several theories of metabolic ecology. For adult insects, however, the diversity of relationships between body mass and respiration remains unexplained. The aim of this study is to relate the respiratory metabolism of a parasitoid with body weight and foraging activity. We compared the metabolic rate of groups of starving and host-fed females of the parasitoid Eupelmus vuilleti recorded with respirometry for 7days, corresponding to the mean lifetime of starving females and over half of the lifetime of foraging females. The dynamics of carbohydrate, lipid and protein in the body of foraging females were quantified with biochemical techniques. Body mass and all body nutrients declined sharply from the first day onwards. By contrast, the CO2 produced and the O2 consumed increased steadily. Starving females showed the opposite trend, identifying foraging as the reason for the respiration increase of feeding females. Two complementary physiological processes explain the unexpected relationship between increasing metabolic rate and declining body weight. First, host hemolymph is a highly unbalanced food, and the excess nutrients (protein and carbohydrate) need to be voided, partially through excretion and partially through respiration. Second, a foraging young female produces eggs at an increasing rate during the first half of its lifetime, a process that also increases respiration. We posit that the time-varying metabolic rate contributions of the feeding and reproductive processes supplements the contribution of the structural mass and lead to the observed trend. We extend our explanations to other insect groups and discuss the potential for unification using Dynamic Energy Budget theory.

Gene expression plasticity evolves in response to colonization of freshwater lakes in threespine stickleback.

Phenotypic plasticity is predicted to facilitate individual survival and/or evolve in response to novel environments. Plasticity that facilitates survival should both permit colonization and act as a buffer against further evolution, with contemporary and derived forms predicted to be similarly plastic for a suite of traits. On the other hand, given the importance of plasticity in maintaining internal homeostasis, derived populations that encounter greater environmental heterogeneity should evolve greater plasticity. We tested the evolutionary significance of phenotypic plasticity in coastal British Columbian postglacial populations of threespine stickleback (Gasterosteus aculeatus) that evolved under greater seasonal extremes in temperature after invading freshwater lakes from the sea. Two ancestral (contemporary marine) and two derived (contemporary freshwater) populations of stickleback were raised near their thermal tolerance extremes, 7 and 22 °C. Gene expression plasticity was estimated for more than 14,000 genes. Over five thousand genes were similarly plastic in marine and freshwater stickleback, but freshwater populations exhibited significantly more genes with plastic expression than marine populations. Furthermore, several of the loci shown to exhibit gene expression plasticity have been previously implicated in the adaptive evolution of freshwater populations, including a gene involved in mitochondrial regulation (PPARAa). Collectively, these data provide molecular evidence that highlights the importance of plasticity in colonization and adaptation to new environments.

On-line monitoring of the transesterification reaction between triglycerides and ethanol using near infrared spectroscopy combined with gas chromatography.

Many analytical procedures have been developed to determine the composition of reaction mixtures during transesterification of vegetable oils with alcohols. However, despite their accuracy, these methods are time consuming and cannot be easily used for on-line monitoring. In this work, a fast analytical method was developed to on-line monitor the transesterification reaction of high oleic sunflower oil with ethanol using Near InfraRed spectroscopy and a multivariate approach. The reactions were monitored through sequential scans of the reaction medium with a probe in a one-liter batch reactor without collecting and preparing samples. To calibrate the NIR analytical method, gas chromatography-flame ionization detection was used as a reference method. The method was validated by studying the kinetics of the EtONa-catalyzed transesterification reaction. Activation energy (51.0 kJ/mol) was also determined by considering a pseudo second order kinetics model.