Phytophagous insects commonly interact through shared host plants. These interactions, however, do not occur in accordance with traditional paradigms of competition, and competition in phytophagous ...insects is still being defined. It remains unclear, for example, if particular guilds of insects are superior competitors or important players in structuring insect communities. Gall-forming insects are likely candidates for such superior competitors because of their ability to manipulate host plants, but their role as competitors is understudied. We investigate the effect of invasive populations of an oak gall wasp,
Neuroterus saltatorius
, on a native specialist butterfly,
Erynnis propertius
, as mediated by their shared host plant,
Quercus garryana
. This gall wasp occurs at high densities in its introduced range, where we stocked enclosures with caterpillars on trees that varied in gall wasp density. Biomass production of butterflies was lower in enclosures on high-density than on low-density trees because overwintering caterpillars were smaller, and fewer of them eclosed into adults the following spring. To see if the gall wasp induced changes in foliar quality, we measured host plant quality before and after gall induction on 30 trees each at two sites. We found a positive relationship between gall wasp density and the percentage change in foliar C:N, a negative relationship between gall wasp density and the percentage change in foliar water at one site, and no relationship between the percentage change in protein-binding capacity (i.e., phenolics) and gall-wasp density. Additionally, there was a negative relationship between foliar quality and butterfly performance. Our results provide evidence for a plant-mediated impact of an invasive oak gall wasp on a native butterfly and suggest that gall wasps could act as superior competitors, especially when they occur at high densities.
Chitooligosaccharides (COS) have attracted attention from industry and academia in various fields due to their diverse bioactivities. However, their conventional chemical production is ...environmentally unfriendly and in addition, defined and pure molecules are both scarce and expensive. A promising alternative is the
synthesis of desired COS in microbial platforms with specific chitin synthases enabling a more sustainable production. Hence, we examined the whole cell factory approach with two well-established microorganisms-
and
-to produce defined COS with the chitin synthase NodC from
sp. GRH2. Moreover, based on an
model of the synthase, two amino acids potentially relevant for COS length were identified and mutated to direct the production. Experimental validation showed the influence of the expression system, the mutations, and their combination on COS length, steering the production from originally pentamers towards tetramers or hexamers, the latter virtually pure. Possible explanations are given by molecular dynamics simulations. These findings pave the way for a better understanding of chitin synthases, thus allowing a more targeted production of defined COS. This will, in turn, at first allow better research of COS' bioactivities, and subsequently enable sustainable large-scale production of oligomers.
Considerable uncertainty surrounds projections of climate change and its ecological consequences. We surveyed 2329 environmental biologists and found that greater expertise is associated with ...projections of greater climatic change and more severe consequences. The opinions of scientists with greater expertise converge, and they expect larger temperature increases, higher percentages of species extinctions, and a high percentage of species' ranges will change in response to climate change over the next 100 years. Importantly, even the highest of these estimates is at the lower bounds of many published projections of climate change and threats to biodiversity. These findings suggest that experts are relatively conservative and discerning about the magnitude of climate change and its biodiversity effects, but even their conservative estimates are substantial. We suggest that policymakers consult environmental biologists on emerging and controversial issues such as climate change and use transparent, standardized metrics of expertise when deciding which scientists to consult.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Synthesizing tetrahydrocannabinol is a lengthy process with minimal yields and little applicability on an industrial scale. To close the gap between bench chemistry and industry process chemistry, ...this paper introduces a small-scale flow chemistry method that utilizes a microwave or ultrasonic medium to produce major tetrahydrocannabinol isomers. This process produces excellent yields and minimal side products, which leads to more efficient large-scale production of the desired cannabinoids.
Local adaptation of populations could preclude or slow range expansions in response to changing climate, particularly when dispersal is limited. To investigate the differential responses of ...populations to changing climatic conditions, we exposed poleward peripheral and central populations of two Lepidoptera to reciprocal, common‐garden climatic conditions and compared their whole‐transcriptome expression. We found evidence of simple population differentiation in both species, and in the species with previously identified population structure and phenotypic local adaptation, we found several hundred genes that responded in a synchronized and localized fashion. These genes were primarily involved in energy metabolism and oxidative stress, and expression levels were most divergent between populations in the same environment in which we previously detected divergence for metabolism. We found no localized genes in the species with less population structure and for which no local adaptation was previously detected. These results challenge the assumption that species are functionally similar across their ranges and poleward peripheral populations are preadapted to warmer conditions. Rather, some taxa deserve population‐level consideration when predicting the effects of climate change because they respond in genetically based, distinctive ways to changing conditions.
Commercial polysiloxanes filled with alumina nano-particles have been employed for the preparation of β-SiAlON-based ceramics in the temperature range 1450–1550°C in nitrogen atmosphere. The ...formation of β-SiAlON was found to be preceded by the formation of intermediate alumino-silicate phases. The SiAlON yield was affected by the occurrence of phase separation in the oxycarbide ceramic residue (SiOC) derived from the silicones and by the partial vaporization of silica, by reduction into gaseous SiO, leading to products with an oxide contamination, consisting of corundum. Filled silicones finally found a promising application in the ceramic joining, sandwiched between two pre-existing α–β (Yb-)SiAlON pieces and treated at high temperature (1550°C): with a proper formulation, a significant inter-diffusion was observed between the joining layer and the SiAlON parts, causing the evolution of a homogeneous joint region, matching the microstructure and the mechanical properties of the parent ceramics. The pre-oxidation of the SiAlON, generally aiding the wetting of the joining media prior to thermal treatment, showed no significant benefit on the microstructure. On the contrary, the addition of a small load during the thermal treatment allowed the formation of strong joints, not exhibiting any significant difference in mechanical properties with the parent material.
ABSTRACT
This study explores the sensitivity of high‐resolution mesoscale simulations of urban heat island (UHI) in the Chicago metropolitan area (CMA) and its environs to urban physical ...parameterizations, with emphasis on the role of lake breeze. A series of climate downscaling experiments were conducted using the urban‐Weather Research and Forecasting (uWRF) model at 1‐km horizontal resolution for a relatively warm period with a strong lake breeze. The study employed best available morphological data sets, selection of appropriate urban parameters, and estimates of anthropogenic heating sources for the CMA. Several urban parameterization schemes were then evaluated using these parameter values. The study also examined (1) the impacts of land data assimilation for initialization of the mesoscale model, (2) the role of urbanization on UHI and lake breeze, and (3) the effects of sub‐grid scale land‐cover variability on urban meteorological predictions. Comparisons of temperature and wind simulations with station observations and Moderate Resolution Imaging Spectroradiometer satellite data in the CMA showed that uWRF, with appropriate selection of urban parameter values, was able to reproduce the measured near‐surface temperature and wind speeds reasonably well. In particular, the model was able to capture the observed spatial variation of 2‐m near‐surface temperatures at night, when the UHI effect was pronounced. Results showed that inclusion of sub‐grid scale variability of land‐use and initializing models with more accurate land surface data can yield improved simulations of near‐surface temperatures and wind speeds, particularly in the context of simulating the extent and spatial heterogeneity of UHI effects.
1. Herbivores that forage on resources that change over time may be strongly affected by environmental factors that alter their temporal overlap with host plants. The magnitude of these effects may ...be mediated by the availability of alternative hosts and by behavioural adaptations for foraging on temporal food resources. 2. This study examines the temporal interaction of a butterfly species and its two host plants to determine how larvae utilize their host resources and are affected by conditions of accelerated host senescence. By changing host use over time, this butterfly may track temporal declines in host quality and buffer the impacts of environmental variation and change. At the same time, it is hypothesized that host declines and changes in the host environment affect larval survivorship and hence butterfly population size. 3. With three sets of field and greenhouse experiments, the following were examined: (i) larval host plant use and the dependence of larval diet on oviposition, (ii) nutritional differences between hosts, and (iii) the impact of conditions that accelerate host plant death (i.e. temperature) on larval survivorship and growth. 4. Larvae were observed to forage widely, vary their diet through time, and use hosts independently of their natal plant. Larvae tracked changes in host quality by steadily increasing their use of the longer-lasting, but nutritionally variable, host plant. Temperature conditions that accelerated host death actually conferred a survivorship advantage when larvae were able to utilize this host. 5. These results suggest that larval diet choice and movement may be an adaptive strategy for foraging on declining food resources. It also suggests that the net effect of environmental extremes on larvae is strongly mediated by host plant use. Differences in larval survivorship when one or both hosts are available suggest that the long-lasting host is essential to butterfly population persistence. By comparing this mobile taxa to species with fewer host-switching opportunities, we better understand the diversity of foraging strategies of food-limited insects and the effects of environmental change.
In 2011, an experiment was undertaken to examine spring synchrony between the endangered Karner blue butterfly (Lycaeides melissa samuelis) (Kbb) and its obligate host plant, wild blue lupine ...(Lupinus perennis) at Indiana Dunes National Lakeshore (INDU), where the southernmost population of Kbb occurred at the time of this study. From 2012 to 2014, field‐placed Kbb eggs were observed for larvae hatching in conjunction with observations of lupine emergence in oak savanna habitat. In 2012, 61% of Kbb hatched when <5% of lupine had emerged due to an extreme early spring event as compared to subsequent years where temporal overlap was >15% between Kbb and lupine. Laboratory experiments testing the sensitivity of Kbb hatching to warm temperatures during the winter of 2011–2012 confirmed that Kbb eggs were susceptible to temperature‐induced hatching. In the summer of 2012, second generation Kbb larvae feeding on sun‐exposed lupine had higher mortality due to the heat and drought conditions that resulted in earlier plant senescence. Following 2012, Kbb were no longer observed at INDU. This observation illustrates the pressing need for adaptive management strategies that account for extreme weather events brought on by climate change.
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