The Role of Temperature, Wind Speed, and Precipitation on the Abundance of Culex Species and West Nile Virus Infection Rate in Rural West-Central Illinois

While most research on West Nile virus (WNV) and its main vector, the Culex mosquito, has been conducted in laboratory or urban settings, studies with field-caught mosquitoes in rural areas, such as west-central Illinois, are lacking. The objective of this research was to investigate key abiotic factors using macroclimate data, including temperature, precipitation, and wind speed, to determine their influence on field-caught mosquito abundance in 4 rural counties in Illinois from 2014 to 2016. Additionally, the relationship between minimum infection rate (MIR) and thermal time was examined. Using gravid traps at 15 sites, Culex mosquitoes were collected twice a week. A total of 5,255 adult female Culex mosquitoes (Cx. pipiens, Cx. quinquefasciatus, and Cx. restuans) were collected in 2014; 9,138 in 2015; and 5,702 in 2016. Regression models were developed based on outcomes of relationships between field-caught mosquitoes and abiotic factors. Precipitation and thermal time had the most significant relationship with mosquito abundance (r2 = 0.993 and r2 = 0.993, respectively), while wind speed was less (r2 = 0.714). The greatest number of Culex and the highest annual MIR were observed in 2015, which was also the driest of the 3 sampling seasons. Mosquito abundance was observed to increase with warmer degree days and MIR was found to increase with abundance in mosquitoes. These models can be used for other mosquito surveillance and monitoring studies in various climate types and environments.

Impacts of abiotic factors on the growth of three commercial biological control agents, on the growth and mycotoxinogenesis of Fusarium graminearum and on their interaction

BACKGROUND

Evolving climatic conditions impact the behavior of microorganisms. The lack of efficiency of beneficial microorganisms against pathogens can be due to these evolving abiotic factors more favorable to the development and adaptation of pathogens. It is therefore of great interest to understand their impact (especially temperature increase and relative humidity (RH) variation) on pathogenic and non-pathogenic microorganisms. This work aimed to examine the possible effects of increasing temperature (20, 25, 30 and 33 °C) and RH (40%, 50%, 60% and 80%) on the growth and mycotoxin production (deoxynivalenol (DON) and zearalenone (ZEN)) of Fusarium graminearum, on the growth of three commercial biocontrol agents (BCAs; Mycostop®, Xedavir® and Polyversum®) and on the pathogen-BCA interaction.

RESULTS

Results demonstrated that BCAs have contrasting impacts on the growth and mycotoxinogenesis of F. graminearum depending on abiotic factors. At 25 °C and regardless of RH, commercial BCAs limit DON production by F. graminearum, but at 30 °C and intermediate RH, Xedavir® is no longer effective. The ability of Xedavir® to control the production of ZEN production by F. graminearum is also affected by abiotic factors. However, increasing temperature has an opposite effect on its ability to control the accumulation of ZEN. Polyversum® oomycete is the BCA with the most resilient efficacy against F. graminearum toxinogenesis under the different abiotic factors.

CONCLUSION

This work provides new knowledge of the effect of these abiotic parameters on the interaction between BCA and F. graminearum, especially on the production of mycotoxins. It paves the way for the development of efficient and resilient mycotoxin biocontrol strategies using beneficial microorganisms against F. graminearum, thus contributing to global food security. © 2023 Society of Chemical Industry.

Factors affecting the nesting success of Swainson's Thrush (Catharus ustulatus) along an elevational gradient

Montane birds experience a range of challenges that may limit their breeding success, including nest predation and severe climactic conditions. The continuing effects of climate change are causing shifts in biotic and abiotic factors that may compound these threats to montane bird species. In northeastern montane forests, many bird species are shifting downslope, potentially as the result of increased precipitation and temperature at higher elevations. Although lower elevations might be more favorable in terms of climactic conditions, nest predation is higher at lower elevations. Thus, montane birds might be faced with the opposing pressures of adverse climactic conditions at higher elevations and increased predation at lower elevations. We monitored nests of Swainson's Thrush (Catharus ustulatus) along an elevation gradient in the White Mountain National Forest in New Hampshire in 2016, 2018, 2019, and 2021 to examine the effect of biotic and abiotic factors on daily nest survival rate (DSR). Linear time explained the most variation of DSR in AICc model comparison, indicating that DSR decreases across the breeding season. Rain intensity (mm/h) had a weak negative effect on DSR, indicating that heavier rain per hour decreases Swainson's Thrush DSR. Moreover, we found some support for a negative interaction effect of elevation in conjunction with minimum daily temperature: DSR of Swainson's Thrush nests at low elevations (281 m) increased with increasing minimum daily temperatures and decreased at high elevations with increasing minimum daily temperatures. Our results suggest nesting survival of montane breeding birds may be at risk as heavier precipitation events become more frequent and intense due to the changing climate and raises the possibility that other passerine species could be at risk in this system.

Environmental Factors Affecting Monoterpene Emissions from Terrestrial Vegetation

Monoterpenes are volatile organic compounds that play important roles in atmospheric chemistry, plant physiology, communication, and defense. This review compiles the monoterpene emission flux data reported for different regions and plant species and highlights the role of abiotic environmental factors in controlling the emissions of biogenic monoterpenes and their emission fluxes for terrestrial plant species (including seasonal variations). Previous studies have demonstrated the role and importance of ambient air temperature and light in controlling monoterpene emissions, likely contributing to higher monoterpene emissions during the summer season in temperate regions. In addition to light and temperature dependence, other important environmental variables such as carbon dioxide (CO2), ozone (O3), soil moisture, and nutrient availability are also known to influence monoterpene emissions rates, but the information available is still limited. Throughout the paper, we identify knowledge gaps and provide recommendations for future studies.

Weathering the hunt: The role of barometric pressure in predator insects' foraging behaviour

Abiotic factors strongly influence ecological interactions and the spatial distribution of organisms. Despite the essential role of barometric pressure, its influence on insect behaviour remains poorly understood, particularly in predators. The effect of barometric pressure variation can significantly impact biological control programs involving entomophagous insects, as they must efficiently allocate time and energy to search for prey in challenging environments. We investigated how predatory insects from different taxonomic groups (Coleoptera, Dermaptera and Neuroptera) adapt their foraging behaviour in response to variations in barometric pressure (low, medium and high). We also examined the response of different life stages to changes in pressure regimes during foraging activities. Our results showed that the searching time of Doru luteipes (Dermaptera: Forficulidae) was faster in a favourable high-pressure regime, whereas Chrysoperla externa (Neuroptera: Chrysopidae) and Eriopis connexa (Coleoptera: Coccinellidae) had similar searching times under varying pressure regimes. Although no differences in prey feeding time were observed among the studied species, the consumption rate was influenced by low barometric pressure leading to a decrease in the number of preyed eggs. Moreover, we provide novel insights into how hemimetabolous (D. luteipes) and holometabolous (E. connexa) species at different life stages respond to barometric pressure. Doru luteipes nymphs and adults had similar consumption rates across all pressure regimes tested, whereas E. connexa larvae consumed fewer eggs under low barometric pressure, but adults were unaffected. This highlights the importance of investigating how abiotic factors affect insects foraging efficiency and predator-prey interactions. Such studies are especially relevant in the current context of climate change, as even subtle changes in abiotic factors can have strong effects on insect behaviour. Barometric pressure is a key meteorological variable that serve as a warning signal for insects to seek shelter and avoid exposure to weather events that could potentially increase their mortality. Understanding the effects of barometric pressure on predatory insects' behaviour can help us develop more effective pest management strategies and promote the resilience of agroecosystems. We provide new insights into the complex relationship between barometric pressure and predator-prey interactions.

Helminth-host-environment interactions: Looking down from the tip of the iceberg

In 1978, the theory behind helminth parasites having the potential to regulate the abundance of their host populations was formalized based on the understanding that those helminth macroparasites that reduce survival or fecundity of the infected host population would be among the forces limiting unregulated host population growth. Now, 45 years later, a phenomenal breadth of factors that directly or indirectly affect the host-helminth interaction has emerged. Based largely on publications from the past 5 years, this review explores the host-helminth interaction from three lenses: the perspective of the helminth, the host, and the environment. What biotic and abiotic as well as social and intrinsic host factors affect helminths? What are the negative, and positive, implications for host populations and communities? What are the larger-scale implications of the host-helminth dynamic on the environment, and what evidence do we have that human-induced environmental change will modify this dynamic? The overwhelming message is that context is everything. Our understanding of second-, third-, and fourth-level interactions is extremely limited, and we are far from drawing generalizations about the myriad of microbe-helminth-host interactions.Yet the intricate, co-evolved balance and complexity of these interactions may provide a level of resilience in the face of global environmental change. Hopefully, this albeit limited compilation of recent research will spark new interdisciplinary studies, and application of the One Health approach to all helminth systems will generate new and testable conceptual frameworks that encompass our understanding of the host-helminth-environment triad.

Effect of Abiotic Factors on Fumosorinone Production from Cordyceps fumosorosea via Solid-State Fermentation

Cordyceps fumosorosea is an important species in the genus of Cordyceps, containing a variety of bioactive compounds, including fumosorinone (FU). This study was a ground-breaking assessment of FU levels in liquid and solid cultures. The present study focused on the impacts of solid-state fermentation (SSF) using solid substrates (wheat, oat, and rice), as well as the effects of fermentation parameters (pH, temperature, and incubation period), on the generation of FU. All the fermentation parameters had significant effects on the synthesis of FU. In a study of 25 °C, 5.5 pH, and 21 days of incubation period combinations calculated -to give maximal FU production, it was found that the optimal values were 25 °C, 5.5 pH, and 21 days, respectively. In a solid substrate medium culture, FU could be produced from SSF. At 30 days, a medium composed of rice yielded the most FU (798.50 mg/L), followed by a medium composed of wheat and oats (640.50 and 450.50 mg/L), respectively. An efficient method for increasing FU production on a large scale could be found in this approach. The results of this study might have multiple applications in different industrial fermentation processes.

Prevalence, Identity, Pathogenicity, and Infection Dynamics of Botryosphaeriaceae Causing Avocado Branch Canker in California

Botryosphaeria branch canker and dieback of avocado (Persea americana Mill.) has expanded in avocado-growing areas in recent years. Twenty-one avocado groves in the major producing regions of California were surveyed in 2018 and 2019. Monthly inoculations of wounded, green, and lignified branches of 'Hass' and 'Lamb Hass' were conducted. Botryosphaeriaceae were the predominant fungi recovered from cankered tissues collected across the surveyed traditional and high-density orchards and caused symptoms on all six sampled cultivars. These fungi were also recovered in asymptomatic twigs and other organs and thus exist as a potential reservoir for future infections. Molecular analyses of 173 isolates showed that Neofusicoccum luteum had the greatest incidences across sites and cultivars, with 83 and 29% recovered from Hass and Lamb Hass, respectively. Pathogenicity tests on excised (Hass, GEM, and Hass mutants) and attached shoots from potted (Hass) and mature avocado trees (Hass and Lamb Hass) showed that all species were pathogenic on wounded, green, and mature branches of the specified cultivars. Monthly inoculations of wounded, green, and lignified branches of Hass and Lamb Hass showed that both stem types were susceptible throughout the inoculation periods, regardless of the avocado phenological stage. In temperature-dependent growth and infection studies, growth of three points could vary during the growing season. Botryosphaeriaceae grown was higher between 20 and 30°C, but only Lasiodiplodia theobromae significantly grew and caused external lesions at 35°C. Lasiodiplodia theobromae also grew more on perseitol-amended media, all indicating its adaptation to warmer temperatures and capacity in metabolizing the avocado-produced sugar. Overall, this study extended our knowledge of the prevalence, identity, and pathogenicity of Botryosphaeriaceae on avocado cultivars, which will be useful to tailor management strategies.

Intraspecific Variation in Functional Traits of Medicago sativa Determine the Effect of Plant Diversity and Nitrogen Addition on Flowering Phenology in a One-Year Common Garden Experiment

Nitrogen deposition and biodiversity alter plant flowering phenology through abiotic factors and functional traits. However, few studies have considered their combined effects on flowering phenology. A common garden experiment with two nitrogen addition levels (0 and 6 g N m-2 year-1) and five species richness levels (1, 2, 4, 6, and 8) was established. We assessed the effects of nitrogen addition and plant species richness on three flowering phenological events of Medicago sativa L. via changes in functional traits, soil nutrients, and soil moisture and temperature. The first flowering day was delayed, the last flowering day advanced, and the flowering duration shortened after nitrogen addition. Meanwhile, the last flowering day advanced, and flowering duration shortened along plant species richness gradients, with an average of 0.64 and 0.95 days change per plant species increase, respectively. Importantly, it was observed that plant species richness affected flowering phenology mainly through changes in plant nutrient acquisition traits (i.e., leaf nitrogen and carbon/nitrogen ratio). Our findings illustrate the non-negligible effects of intraspecific variation in functional traits on flowering phenology and highlight the importance of including functional traits in phenological models to improve predictions of plant phenology in response to nitrogen deposition and biodiversity loss.

Influence of Seasonality and Culture Stage of Farmed Nile Tilapia (Oreochromis niloticus) with Monogenean Parasitic Infection

The aim of this study was to observe how abiotic and biotic factors in a tropical region influence the rate of monogenean parasitism in Nile tilapia (Oreochromis niloticus) that are farmed in net cages. A total of 240 sexually reversed fish were analyzed, and 20 from each culture stage were collected during each sampling month. Overall, 60 fish were sampled in April (autumn), 60 in August (winter), 60 in November (spring), and 60 in February (summer). Fish were collected from a commercial fish farm located in Capivara Reservoir in the lower Paranapanema River region of Paraná, Brazil. In total, 3290 monogenean parasites were collected from fish gills of the following species: Cichlidogyrushalli, C. thurstonae, Scutogyruslongicornis, C. cirratus, C. sclerosus, and C. tilapiae. Higher parasitological indices were observed in colder seasons with lower precipitation. Autumn had the highest parasitic infection values compared to the other seasons. The occurrence of monogenean parasites showed a negative correlation with season, in contrast to the culture stage, in which there was a positive correlation. These results may provide a means for establishing adequate fish farm management to predict periods of high monogenean infestation.

Persistence of a Wild-Type Virulent Aeromonas hydrophila Isolate in Pond Sediments from Commercial Catfish Ponds: A Laboratory Study

Virulent Aeromonas hydrophila (vAh) is a major bacterial pathogen in the U.S. catfish industry and is responsible for large-scale losses within commercial ponds. Administering antibiotic feeds can effectively treat vAh infections, but it is imperative to discern new approaches and better understand the mechanics of infection for this bacterium. As such, the persistence of vAh in pond sediments was determined by conducting laboratory trials using sediment from four commercial catfish ponds. Twelve chambers contained sterilized sediment, vAh isolate ML-09-119, and 8 L of water maintained at 28 °C and were aerated daily. At 1, 2, 4, 6, and 8 days, and every 7th day post-inoculation for 28 days, 1 g of sediment was removed, and vAh colony forming units (CFU) were enumerated on ampicillin dextrin agar. Viable vAh colonies were present in all sediments at all sampling periods. The vAh growth curve peaked (1.33 ± 0.26 × 10⁹ CFU g^-1) at 96 h post-inoculation. The population plateaued between days 14 and 28. No correlations were found between CFU g^-1 and physiochemical sediment variables. This study validated the ability of vAh to persist within pond sediments in a laboratory setting. Further research on environmental factors influencing vAh survivability and population dynamics in ponds is needed.

Orchid-mycorrhizal fungi interactions reveal a duality in their network structure in two European regions differing in climate

Network analysis is an effective tool to describe and quantify the ecological interactions between plants and root-associated fungi. Mycoheterotrophic plants, such as orchids, critically rely on mycorrhizal fungi for nutrients to survive, therefore, investigating the structure of those intimate interactions brings new insights on the plant community assembly and coexistence. So far, there is little consensus on the structure of those interactions, described either as nested (generalist interactions), modular (highly specific interactions) or of both topologies. Biotic factors (e.g., mycorrhizal specificity) were shown to influence the network structure, while there is less evidence of abiotic factor effects. By using next-generation sequencing of the orchid mycorrhizal fungal (OMF) community associated to 238 plant individuals belonging to 17 orchid species, we assessed the structure of four orchid-OMF networks in two European regions under contrasting climatic conditions (Mediterranean vs Continental). Each network contained four to 12 co-occurring orchid species, including six species shared among the regions. All four networks were both nested and modular, and fungal communities were different between co-occurring orchid species, despite multiple sharing of fungi across some orchids. Co-occurring orchid species growing in Mediterranean climate were associated to more dissimilar fungal communities, consistent with a more modular network structure compared to the Continental ones. The OMF diversity was comparable among orchid species since most orchids were associated with multiple rarer fungi and with only a few highly dominant ones in the roots. Our results provide useful highlights on potential factors involved in structuring plant-mycorrhizal fungi interactions in different climatic conditions.

Prediction of biological development effects on drag forces of ceramic hull coating using Reynolds-averaged Navier-Stokes-based solver

Ships in service feature surfaces that exhibit biofouling, which alters the hydrodynamics of the vessels, thus affecting their normal displacement and significantly increasing their fuel consumption. The application of three types of ceramic coatings as ecological, effective and durable alternatives to commercial silicone-based marine coatings is investigated in this study. Three different ceramic glazes and two control commercial paints are analysed in an actual environment during 20 months of exposure to simulate the navigation conditions such that growth and roughness data can be obtained and then applied to computational fluid dynamics (CFD) software using an open-source Reynolds-averaged Navier-Stokes solver. The CFD results are validated under smooth hull conditions with a full-scale Kriso Container Ship (KCS) model and with different levels of hull roughness. The developed approach shows that the drag in hulls coated with conventional paint is 19% greater than that in hulls with ceramic coating.

Fungi That Promote Plant Growth in the Rhizosphere Boost Crop Growth

The fungi species dwelling in the rhizosphere of crop plants, revealing functions that endeavor sustainability of the plants, are commonly referred to as 'plant-growth-promoting fungi' (PGPF). They are biotic inducers that provide benefits and carry out important functions in agricultural sustainability. The problem encountered in the agricultural system nowadays is how to meet population demand based on crop yield and protection without putting the environment and human and animal health at risk based on crop production. PGPF including Trichoderma spp., Gliocladium virens, Penicillium digitatum, Aspergillus flavus, Actinomucor elegans, Podospora bulbillosa, Arbuscular mycorrhizal fungi, etc., have proven their ecofriendly nature to ameliorate the production of crops by improving the growth of the shoots and roots of crop plants, the germination of seeds, the production of chlorophyll for photosynthesis, and the abundant production of crops. PGPF's potential mode of action is as follows: the mineralization of the major and minor elements required to support plants' growth and productivity. In addition, PGPF produce phytohormones, induced resistance, and defense-related enzymes to inhibit or eradicate the invasion of pathogenic microbes, in other words, to help the plants while encountering stress. This review portrays the potential of PGPF as an effective bioagent to facilitate and promote crop production, plant growth, resistance to disease invasion, and various abiotic stresses.

Scale-dependent effects of species diversity on aboveground biomass and productivity in a subtropical broadleaved forest on Mt. Huangshan

The relationship between species diversity and biomass/productivity is a major scientific question in ecology. Exploring this relationship is essential to understanding the mechanisms underpinning the maintenance of biodiversity. Positive, negative, and neutral relationships have been identified in controlled experiments and observational research. However, increasing evidence suggests that the effects of species diversity on aboveground biomass and productivity are influenced by biotic and abiotic factors, but it remains unclear whether scale-dependent effects affect aboveground biomass and productivity. Herein, we used a generalized linear regression model and a structural equation model to explore relationships between species diversity and productivity/aboveground biomass under different scales and to investigate the effects of topographical factors and species diversity on ecosystem functioning. The results revealed a positive relationship between biodiversity and ecosystem functioning based on species diversity and aboveground biomass. Different sampling scales may impact the relationship between species diversity and ecosystem functioning. A positive relationship was found between species richness and productivity at medium and large scales; however, ambiguous relationships were found in productivity and other species diversity indices. Elevation was a key factor affecting both biomass and productivity. These results suggest that species diversity is not the only factor affecting biomass and productivity, and the positive correlation between species diversity and ecosystem functioning is mediated by abiotic factors.

Investigating the interactive effects of temperature, pH, and salinity on Naegleria fowleri persistence

Naegleria fowleri causes primary amoebic meningoencephalitis, a deadly infection that occurs when free-living amoebae enter the nose via freshwater and travel to the brain. N. fowleri naturally thrives in freshwater and soil and is thought to be associated with elevated water temperatures. While environmental and laboratory studies have sought to identify what environmental factors influence its presence, many questions remain. This study investigated the interactive effects of temperature, pH, and salinity on N. fowleri in deionized and environmental waters. Three temperatures (15, 25, 35°C), pH values (6.5, 7.5, 8.5), and salinity concentrations (0.5%, 1.5%, 2.5% NaCl) were used to evaluate the growth of N. fowleri via ATP luminescent assays. Results indicated N. fowleri grew best at 25°C, and multiple interactive effects occurred between abiotic factors. Interactions varied slightly by water type but were largely driven by temperature and salinity. Lower temperature increased N. fowleri persistence at higher salinity levels, while low salinity (0.5% NaCl) supported N. fowleri growth at all temperatures. This research provided an experimental approach to assess interactive effects influencing the persistence of N. fowleri. As climate change impacts water temperatures and conditions, understanding the microbial ecology of N. fowleri will be needed minimize pathogen exposure.

Distinct leaf functional traits of Tamarix chinensis at different habitats in the hinterland of the Taklimakan desert

Leaf functional traits reflect plant adaptive strategies towards environmental heterogeneity. However, which factor play the key role of plasticity of leaf functional traits among various variable environmental factors remains unclear in desert hinterland oasis area. Here, we analyzed variations in leaf water content (LWC), δ ¹³C values of leaves (δ ¹³C), specific leaf area (SLA), leaf organic carbon concentration (LOC), leaf total nitrogen concentration (LTN), leaf total phosphorus concentration (LTP), and leaf C: N: P stoichiometry in Tamarix chinensis growing in five habitats at the Daliyabuyi, a natural pristine oasis in northwestern China, that differ abiotically and biotically. The spatial heterogeneity of leaf functional traits was evident. Abiotic factors vitally influence leaf functional traits, of which groundwater depth (GWD) and soil C: N stoichiometry (SOC: STN) are crucial. GWD exhibited close relationships with LWC (P < 0.05) and LOC: LTP (P < 0.01), but not δ ¹³C. Soil water content (SWC) and SOC: STN were negatively related to SLA (P < 0.01; P < 0.05). While, SOC: STN showed positive relationships with LOC: LTN (P < 0.05). As for biological factors, we found T. chinensis in habitat with Sophora alopecuroidies had the highest LTN, possibly as a result of N fixation of leguminous plants (S. alopecuroidies) promotes the N concentration of T. chinensis. Close relationships also existed between leaf functional traits, LWC showed significantly negatively relatd to δ ¹³C, LOC: LTN and LOC: LTP (P < 0.05), whereas δ ¹³C had positively correlated with LOC: LTN (P < 0.01) but negatively correlated with LTN (P < 0.05). T. chinensis had relative higher LWC couple with lower δ ¹³C, and exhibiting lower C, N, P in leaves and their stoichiometric ratios, and also lower SLA which compared with other terrestrial plant. Such coordinations suggesting that T. chinensis develops a suite of trait combinations mainly tends to more conservative to response local habitats in Daliyabuyi, which is contribute to understand desert plant resource acquisition and utilization mechanisms in extremely arid and barren environments.

Contrasting influences of two dominant plants, Dasiphora fruticosa and Ligularia virguarea, on aboveground and belowground communities in an alpine meadow

Soil organisms are abundant, phylogenetically and functionally diverse, and interact to catalyse and regulate critical soil processes. Understanding what structures belowground communities is therefore fundamental to gaining insight into ecosystem functioning. Dominant plants have been shown to influence belowground communities both directly and indirectly through changes in abiotic and biotic factors. In a field study, we used piecewise structural equation modelling to disentangle and compare the effects of a dominant allelopathic plant, Ligularia virgaurea, and a dominant facilitative plant, Dasiphora fruticosa, on understory plant, soil microbial and nematode community composition in an alpine meadow on the Tibetan plateau. Dasiphora fruticosa was associated with changes in edaphic variables (total nitrogen, soil organic carbon, pH and ammonium), understory plant and soil bacterial communities, whereas Ligularia virguarea was associated with increased soil ammonium content and soil fungal richness relative to dominant plant-free control plots. Moreover, nematode richness was significantly greater under D. fruticosa, with no change in nematode community composition. By contrast, nematode richness under Ligularia virgaurea was similar to that of dominant plant-free control plots, but nematode community composition differed from the control. The effects of both plants were predominantly direct rather than mediated by indirect pathways despite the observed effects on understory plant communities, soil properties and microbial assemblages. Our results highlight the importance of plants in determining soil communities and provide new insight to disentangle the complex above- and belowground linkages.

Phytoplankton Community Response to Environmental Factors along a Salinity Gradient in a Seagoing River, Tianjin, China

A river-estuary ecosystem usually features a distinct salinity gradient and a complex water environment, so it is enormously valuable to study the response mechanism of living organisms to multiple abiotic factors under salinity stress. Phytoplankton, as an important part of aquatic microorganisms, has always been of concern for its crucial place in the aquatic ecosystem. In this study, phytoplankton data and 18 abiotic factors collected from 15 stations in Duliujian River, a seagoing river, were investigated in different seasons. The results showed that the river studied was of a Cyanophyta-dominant type. Salinity (SAL) was the key control factor for phytoplankton species richness, while water temperature (WT) was critical not only for species richness, but also community diversity, and the abundance and biomass of dominant species. Apart from WT, the abundance and biomass of dominant species were also driven by total nitrogen (TN), nitrate (NO₃^-), pH, and water transparency (SD). Moreover, total dissolved phosphorus (TDP), pH, and chemical oxygen demand (COD) were crucial for community diversity and evenness. The bloom of dominant species positively associated with TDP led to lower diversity and evenness in autumn. In addition, when available nitrogen was limited, Pseudoanabaena sp. could obtain a competitive advantage through the N₂ fixation function. Increased available nitrogen concentration could favor the abundance of Chlorella vulgaris to resist the negative effect of WT. The results show that Oscillatoria limosa could serve as an indicator of organic contamination, and nutrient-concentration control must be effective to inhibit Microcystis bloom. This could help managers to formulate conservation measures.

Prognostic of Yield of Potatoes of Promising Domestic Varieties under the Impact of Stress Abiotic Factors

Twenty-four potato (Solanum tuberosum L.) varieties differing in ripening groups (early, middle-early, and mid-season-ripening) were studied. Potatoes were grown under the conditions of the Middle Volga region of Russia in 2019-2021. It was found statistically that the yield (t/ha) of the early and mid-season-ripening varieties was negatively correlated with the increase in average temperatures during the growing season from May to August (R = -0.97, p = 0.04). Soil moisture content at a depth of 20 cm was positively correlated with the yield of middle-early varieties (R = 0.97, p = 0.04). The average tuber weight in the early varieties was sensitive to the increase in average temperatures (R = -0.95, p = 0.04). An increase in soil moisture content was beneficial to the average tuber weight (R = 0.98, p = 0.04), though only in the middle-early and mid-season-ripening groups. However, the soil moisture content and the tuber numbers in the mid-season-ripening varieties were negatively correlated (R = -0.96, p = 0.05).

Soil Fungal Composition Drives Ecosystem Multifunctionality after Long-Term Field Nitrogen and Phosphorus Addition in Alpine Meadows on the Tibetan Plateau

An ecosystem can provide multiple functions and services at the same time, i.e., ecosystem multifunctionality (EMF). Above- and belowground biodiversity and abiotic factors have different effects on EMF. Human activities increase atmospheric nitrogen (N) and phosphorus (P) deposition, but the mechanism of how atmospheric N and P deposition affect EMF in alpine meadows on the Tibetan Plateau is still unclear. Here, we measured eleven ecosystem parameters to quantify EMF by averaging method and explored the impact of plant and microbial species diversity and abiotic factors on EMF after long-term field N and P addition in alpine meadows on the Tibetan Plateau. Results showed that N addition reduced EMF by 15%, NP increased EMF by 20%, and there was no change due to P addition. N and P addition reduced pH, relative light conditions (RLC), and plant species richness and modified plant and fungal community composition. Structural equation model (SEM) analysis confirmed that fungal community composition was an important and positive driver on EMF. These results provided an understanding of how N and P addition affect EMF directly and indirectly through biotic and abiotic pathways, which was important for predicting the response of EMF to atmospheric N and P deposition in the future. Furthermore, the findings suggested that soil fungal composition was more important driving factors than abiotic factors in the response of EMF to N and P addition and the importance of the interactions between plant and soil microbial species diversity in supporting greater EMF.

Effect of surrounding landscape on Popillia japonica abundance and their spatial pattern within Wisconsin vineyards

Landscapes surrounding agroecosystems can provide resources that may benefit insect pests. This project examined the influence of the surrounding landscape on the abundance and spatial pattern of Popillia japonica (Coleoptera: Scarabaeidae) in vineyards. Twenty vineyards across Southern Wisconsin, spanning a gradient of 5-80% cropland in a 1.5km radius surrounding landscape, were sampled in 2017 and 2018 for P. japonica adults and leaf injury. The distribution of P. japonica and leaf injury was assessed by sampling along a transect at the edge, halfway from the edge to the center, and at the center of each vineyard. The proportion of cropland and pasture in the surrounding landscape along with abiotic factors of temperature, precipitation, longitude, and pesticide use (determined using Environmental Impact Quotient) were included in models to explain the variation of P. japonica abundance and leaf injury. No significant relationship was observed between proportion cropland in the surrounding landscape and P. japonica abundance or leaf injury. Combined effects of pasture, longitude, and temperature best explained variation in the abundance of P. japonica adults while longitude, temperature and EIQ best explained variability in leaf injury. Vineyards with more pastures in the surrounding landscape, located further east, and with higher temperatures, generally had more P. japonica adults and vineyards further east with higher temperature and lower EIQ pesticide use generally had higher levels of leaf injury. Additionally, variability in weekly temperature and precipitation influenced weekly abundance, with higher temperatures and less precipitation resulting in greater weekly abundance of P. japonica adults. Significantly more adult P. japonica and greater leaf injury were found at the edges than in the center of vineyards. Our results suggest beetles from the surrounding landscape likely contribute to populations of P. japonica adults found feeding on vines on vineyard edges, and P. japonica abundance and associated leaf injury are influenced by geographical location, local weather conditions, and pesticide use.

Extrinsic and intrinsic factors influencing the emergence and return of the Asian particolored bat Vespertilio sinensis to the summer roost

Circadian rhythms play a crucial role in the health and survival of organisms. However, little is known concerning how intrinsic and extrinsic factors affect animal daily rhythms in the field, especially in nocturnal animals. Here, we investigated the first emergence, mid-emergence, and return times of Vespertilio sinensis, and also integrated environmental conditions (temperature, humidity, and light intensity) and biotic factors (reproductive status and predation risk) to determine causes of variation in the activity rhythms of the bats. We found that variation in the first emergence time, the mid-emergence time, and the final return time were distinct. The results demonstrated that the emergence and return times of bats were affected by light intensity, reproductive status, and predation risk in a relatively complex pattern. Light intensity had the greatest contribution to activity rhythms. Moreover, we first investigated the effects of actual predators on the activity rhythms of bats; the results showed that the mid-emergence time of bats was earlier as predators were hunting, but the final return time was later when predators were present. Finally, our results also highlighted the importance of higher energy demands during the lactation in bats to variation in activity rhythms. These results improve our understanding of the patterns and causes of variation in activity rhythms in bats and other nocturnal animals.

Population-specific responses of floral volatiles to abiotic factors in changing environments

PREMISE

Shifts in abiotic factors can affect many plant traits, including floral volatiles. This study examined the response of floral volatiles to water availability and whether phenotypic plasticity to water availability differs among populations. It also investigated genetic differentiation in floral volatiles, determined the effect of temperature on phenotypic plasticity to water availability, and assessed temporal variation in floral scent emission between day and evening, since pollinator visitation differs at those times.

METHODS

Rocky Mountain columbine plants (Aquilegia coerulea), started from seeds collected in three wild populations in Colorado, Utah, and Arizona, were grown under two water treatments in a greenhouse in Madison, Wisconsin, United States. One population was also grown under the two water treatments, at two temperatures. Air samples were collected from enclosed flowers using dynamic headspace methods and floral volatiles were identified and quantified by gas chromatography (GC) with mass spectrometry (MS).

RESULTS

Emission of three floral volatiles increased in the wetter environment, indicating phenotypic plasticity. The response of six floral volatiles to water availability differed among populations, suggesting genetic differentiation in phenotypic plasticity. Five floral volatiles varied among populations, and emission of most floral volatiles was greater during the day.

CONCLUSIONS

Phenotypic plasticity to water availability permits a quick response of floral volatiles in changing environments. The genetic differentiation in phenotypic plasticity suggests that phenotypic plasticity can evolve but complicates predictions of the effects of environmental changes on a plant and its pollinators.

Beans, Variety "Arriba Nacional"

Fine flavor cocoa is a unique category of cocoa that produces almonds with high aromatic potential and several sensory benefits that make it different from the basic or ordinary cocoas. Ecuador is the world's leader in the production and export of fine flavor cocoa, responsible for 63% of the world's total production due to the commercialization of the Arriba Nacional variety, known to possess an intense aroma that is unique in the cocoa world market. Besides its organoleptic specificity, this variety represents a source of important bioactive compounds associated with both sensory and health properties. This study evaluates the influence of an abiotic factor, nutritional soil status, on the phytochemical composition (methylxantines and phenolic compounds), and antioxidant and sensory properties of Arriba variety cocoa beans originating from three different geographical regions of Ecuador. We used the Diagnosis and Recommendation Integrated System (DRIS), Folin-Ciocalteau, high-performance liquid chromatography (HPLC), ABTS free-radical-scavenging activity, the α, α-diphenyl-β-picrylhydrazyl free-radical-scavenging method (DPPH), and Ferric reducing antioxidant power (FRAP) analysis to reveal a significant correlation between Mn ions and total phenolic content, a positive implication of N in methylxanthine composition and antioxidant properties, and the importance of Ca, Mg, and K ions in increasing the flavonoid and anthocyanin content of raw cocoa beans. We showed that these nutritional elements can interfere with the nutraceutical and sensory properties of cocoa beans, as Cu, Mg, and K are correlated with anthocyaninic content, while Fe, Ca, P and Zn influenced the flavonoid content. We underline that the Arriba variety is suitable not only for the production of high-quality chocolate, but also for the increasing worldwide nutraceutical market, generating qualitative and competitive products.

Population Dynamics and Tree Damage of the Invasive Chestnut Gall Wasp, Dryocosmus kuriphilus, in Its Southernmost European Distributional Range

Simple Summary

Chestnut cultivation makes it possible to invigorate the economy of many rural areas in Europe. The chestnut gall wasp Dryocosmus kuriphilus is a serious invasive pest that causes severe damage to chestnut cultivation worldwide. Its rapid spread across Europe endangers the continuity of the entire chestnut industry. Despite this growing concern, scarce attention has been paid to the status of D. kuriphilus in its southernmost distributional range in continental Europe and limited knowledge on the factors modelling their populations is available. In this study, we assessed spatio-temporal patterns in the population dynamics, phenology and tree damage in southern Spain, and further evaluated the relationship between these variables and thermal trends. Strong variation in the population dynamics and flight phenology was found both among localities and over time, which was influenced by differences in thermal regimes. Similarly, tree damage evolved differently over time in each locality, thus suggesting that local conditions may determine significant differences in damage evolution. Our work contributes to a better understanding of this pest in countries throughout the Mediterranean basin and can be useful for further improvement of control and management strategies.

Abstract

The invasive chestnut gall wasp (CGW), Dryocosmus kuriphilus, the worst pest of chestnut cultivation, has spread worryingly throughout Europe in less than 20 years. Despite the great concern around this pest, little is known about the status in its southernmost distribution in continental Europe. We assessed spatio-temporal patterns in the population dynamics, phenology and tree damage caused by CGW in southern Spain. Likewise, the relationship between these variables and thermal trends was evaluated. We found strong variation in the population dynamics and flight phenology among localities and over time, which were highly influenced by changes in thermal regimes. Specifically, warmer localities and vegetative periods promoted higher population densities, a partial increase in the survival of immature stages, and advanced flight activity. Moreover, tree damage evolved differently over time in each locality, which suggests that local conditions may determine differences in damage evolution. Our findings evidence that great spatio-temporal variability in the CGW populations takes place across invaded areas in its southernmost European distributional range. Although control mechanisms have been introduced, implementation of further control and management measures are critical to cope with this main threat for the chestnut industry and to prevent its spread to nearing chestnut-producing areas.

Land-Use Type Drives Soil Population Structures of the Entomopathogenic Fungal Genus Metarhizium

Species of the fungal genus Metarhizium are globally distributed pathogens of arthropods, and a number of biological control products based on these fungi have been commercialized to control a variety of pest arthropods. In this study, we investigate the abundance and population structure of Metarhizium spp. in three land-use types—arable land, grassland, and forest—to provide detailed information on habitat selection and the factors that drive the occurrence and abundance of Metarhizium spp. in soil. At 10 sites of each land-use type, which are all part of the Swiss national soil-monitoring network (NABO), Metarhizium spp. were present at 8, 10, and 4 sites, respectively. On average, Metarhizium spp. were most abundant in grassland, followed by forest and then arable land; 349 Metarhizium isolates were collected from the 30 sites, and sequence analyses of the nuclear translation elongation factor 1α gene, as well as microsatellite-based genotyping, revealed the presence of 13 Metarhizium brunneum, 6 Metarhizium robertsii, and 3 Metarhizium guizhouense multilocus genotypes (MLGs). With 259 isolates, M. brunneum was the most abundant species, and significant differences were detected in population structures between forested and unforested sites. Among 15 environmental factors assessed, C:N ratio, basal respiration, total carbon, organic carbon, and bulk density significantly explained the variation among the M. brunneum populations. The information gained in this study will support the selection of best-adapted isolates as biological control agents and will provide additional criteria for the adaptation or development of new pest control strategies.

Comparative Growth Inhibition of Bread Spoilage Fungi by Different Preservative Concentrations Using a Rapid Turbidimetric Assay System

Bread and intermediate moisture bakery products are mainly spoiled by yeasts and filamentous fungi. The inoculum load and preservation system used determines their shelf life. To extend the shelf life of such commodities, the use of chemical preservatives is the most common way to try and control the initiation of mold spoilage of bread. This study has utilized a rapid turbidimetric assay system (Bioscreen C) to examine the temporal efficacy of calcium propionate (CP) and potassium sorbate (PS) for controlling the growth of important bread spoilage fungi. The objectives were to compare the temporal growth of strains of three important spoilage fungi Hyphopichia burtonii (HB17), Paecilomyces variotii (PV11), and Penicillium roqueforti (PR06) isolated from visibly molded bread to (a) different concentrations of CP and PS (0-128 mM), (b) temperatures (25°C, 30°C), (c) water activity (a_w; 0.95, 0.97), and (d) pH (5.0, 5.5). All three abiotic factors, pH, a_w, and temperature, and preservative concentrations influenced the relative growth of the species examined. In general, PS was more effective than CP in inhibiting the growth of the strains of these three species. In addition, the Time to Detection (TTD) for the efficacy of the preservatives under the interacting abiotic factors was compared. The strain of Paecilomyces variotii (PV10) was the most tolerant to the preservatives, with the shortest TTD values for both preservatives. P. roqueforti was the most sensitive with the longest TTD values under all conditions examined. These results are discussed in the context of the evolution of resistance to food-grade preservatives by such spoilage fungi in bakery products.

Characteristics and Research Progress of Legume Nodule Senescence

Delaying the nodule senescence of legume crops can prolong the time of nitrogen fixation and attenuate the lack of fertilizer in the later stage of legume crop cultivation, resulting in improved crop yield and reduced usage of nitrogen fertilizer. However, effective measures to delay the nodule senescence of legume crops in agriculture are relatively lacking. In the present review, we summarized the structural and physiological characteristics of nodule senescence, as well as the corresponding detection methods, providing technical support for the identification of nodule senescence phenotype. We then outlined the key genes currently known to be involved in the regulation of nodule senescence, offering the molecular genetic information for breeding varieties with delayed nodule senescence. In addition, we reviewed various abiotic factors affecting nodule senescence, providing a theoretical basis for the interaction between molecular genetics and abiotic factors in the regulation of nodule senescence. Finally, we briefly prospected research foci of nodule senescence in the future.

Enhancement of Xanthophyll Synthesis in Porphyra/Pyropia Species (Rhodophyta, Bangiales) by Controlled Abiotic Factors: A Systematic Review and Meta-Analysis

Red alga species belonging to the Porphyra and Pyropia genera (commonly known as Nori), which are widely consumed and commercialized due to their high nutritional value. These species have a carotenoid profile dominated by xanthophylls, mostly lutein and zeaxanthin, which have relevant benefits for human health. The effects of different abiotic factors on xanthophyll synthesis in these species have been scarcely studied, despite their health benefits. The objectives of this study were (i) to identify the abiotic factors that enhance the synthesis of xanthophylls in Porphyra/Pyropia species by conducting a systematic review and meta-analysis of the xanthophyll content found in the literature, and (ii) to recommend a culture method that would allow a significant accumulation of these compounds in the biomass of these species. The results show that salinity significantly affected the content of total carotenoids and led to higher values under hypersaline conditions (70,247.91 µg/g dm at 55 psu). For lutein and zeaxanthin, the wavelength treatment caused significant differences between the basal and maximum content (4.16–23.47 µg/g dm). Additionally, in Pyropia spp., the total carotenoids were considerably higher than in Porphyra spp.; however, the lutein and zeaxanthin contents were lower. We discuss the specific conditions for each treatment and the relation to the ecological distribution of these species.

The Gut Microbiome and Abiotic Factors as Potential Determinants of Postprandial Glucose Responses: A Single-Arm Meal Study

The gut microbiome has combined with other person-specific information, such as blood parameters, dietary habits, anthropometrics, and physical activity been found to predict personalized postprandial glucose responses (PPGRs) to various foods. Yet, the contributions of specific microbiome taxa, measures of fermentation, and abiotic factors in the colon to glycemic control remain elusive. We tested whether PPGRs 60 min after a standardized breakfast was associated with gut microbial α-diversity (primary outcome) and explored whether postprandial responses of glucose and insulin were associated with specific microbiome taxa, colonic fermentation as reflected by fecal short-chain fatty acids (SCFAs), and breath hydrogen and methane exhalation, as well as abiotic factors including fecal pH, fecal water content, fecal energy density, intestinal transit time (ITT), and stool consistency. A single-arm meal trial was conducted. A total of 31 healthy (24 female and seven male) subjects consumed a standardized evening meal and a subsequent standardized breakfast (1,499 kJ) where blood was collected for analysis of postprandial glucose and insulin responses. PPGRs to the same breakfast varied across the healthy subjects. The largest inter-individual variability in PPGRs was observed 60 min after the meal but was not associated with gut microbial α-diversity. In addition, no significant associations were observed between postprandial responses and specific taxa of the gut microbiome, measures of colonic fermentation, ITT, or other abiotic factors. However, fasting glucose concentrations were negatively associated with ITT, and fasting insulin was positively associated with fasting breath hydrogen. In conclusion, the gut microbiome, measures of colonic fermentation, and abiotic factors were not shown to be significantly associated with variability in postprandial responses, suggesting that contributions of the gut microbiome, colonic fermentation, and abiotic factors to PPGRs may be subtle in healthy adults.

Settlers of our inner surface - Factors shaping the gut microbiota from birth to toddlerhood

During the first 3 years of life, the microbial ecosystem within the human gut undergoes a process that is unlike what happens in this ecosystem at any other time of our life. This period in time is considered a highly important developmental window, where the gut microbiota is much less resilient and much more responsive to external and environmental factors than seen in the adult gut. While advanced bioinformatics and clinical correlation studies have received extensive focus within studies of the human microbiome, basic microbial growth physiology has attracted much less attention, although it plays a pivotal role to understand the developing gut microbiota during early life. In this review, we will thus take a microbial ecology perspective on the analysis of factors that influence the temporal development of the infant gut microbiota. Such factors include sources of microbes that seed the intestinal environment, physico-chemical (abiotic) conditions influencing microbial growth and the availability of nutrients needed by the intestinal microbes.

Has a river dam affected the life-history traits of a freshwater prawn?

In recent years, species richness and diversity in aquatic ecosystems has declined as environments are increasingly impacted by anthropic actions. Freshwater prawns are well adapted to survive in a disturbed and heterogeneous environment. For instance, Amazon river prawn (Macrobrachium amazonicum) populations vary in migratory behavior between rivers and estuaries, depending on factors such as dams. However, there is limited information on the influence of environmental conditions on life-history traits of this species, which we investigate here using two distinct and unconnected aquatic systems, a dammed river and an estuary, in the eastern Brazilian Amazon. The biological characteristics of M. amazonicum populations in the two environments were compared and related to environmental parameters, which differed significant differences between the two environments and between seasons. Dissolved oxygen, precipitation, and temperature varied most significantly with the seasons in both the estuary and river. M. amazonicum prawns in the estuary were larger and heavier than those in the river during rainy periods. The mass-length ratios and condition factor varied significantly between the M. amazonicum populations in the estuary and river, with negative allometric growth (grows faster in length than in weight) predominating in both populations, and condition factor was better in the estuary for males and in the river for females. The relative frequencies of occurrence of the different female maturation stages and the male morphotypes were related to precipitation and turbidity in both environments and also to salinity in the estuary. In these two distinct aquatic systems, the abiotic parameters determined by the seasonal precipitation cycle profoundly influenced the development of this crustacean, despite its ecological plasticity. Overall, the study showed that river damming triggered environmental changes in the freshwater river ecosystem and played a key role in determining the life-history characteristics of M. amazonicum in these contrasting aquatic systems.

Long-term trends in fruit production in a tropical forest at Ngogo, Kibale National Park, Uganda

Fruit production in tropical forests varies considerably in space and time, with important implications for frugivorous consumers. Characterizing temporal variation in forest productivity is thus critical for understanding adaptations of tropical forest frugivores, yet long-term phenology data from the tropics, in particular from African forests, are still scarce. Similarly, as the abiotic factors driving phenology in the tropics are predicted to change with a warming climate, studies documenting the relationship between climatic variables and fruit production are increasingly important. Here we present data from 19 years of monitoring the phenology of 20 tree species at Ngogo in Kibale National Park, Uganda. Our aims were to characterize short- and long-term trends in productivity and to understand the abiotic factors driving temporal variability in fruit production. Short-term (month-to-month) variability in fruiting was relatively low at Ngogo, and overall fruit production increased significantly through the first half of the study. Among the abiotic variables we expected to influence phenology patterns (including rainfall, solar irradiance, and average temperature), only average temperature was a significant predictor of monthly fruit production. We discuss these findings as they relate to the resource base of the frugivorous vertebrate community inhabiting Ngogo.

Abiotic Factors Promote Cell Penetrating Peptide Permeability in Enterobacteriaceae Models

Conventionally, the delivery of biomolecules into bacteria for the generation of characterized or functional mutants has relied greatly on horizontal gene transfer techniques. However, the low compatibility of these techniques with novel or hard-to-transform bacteria currently serves as a challenge to the bioengineering field. Here, we explored the use of cell penetrating peptides (CPPs) as an alternative biomolecule delivery approach by investigating the effects of the abiotic factors during CPP permeation. Using the (KFF)₃K-FAM conjugate and Escherichia coli as models, we evaluated four abiotic factors where two of these factors, temperature and solution tonicity, promoted (KFF)₃K-FAM permeation efficiency. Our data show that optimal (KFF)₃K-FAM permeation efficiency was achieved for E. coli at approximately 98.1% under conditions of 37°C (growth optimal temperature) and 50% PBS concentration. Based on these conditions, we subsequently tested the applicability of CPP permeation in various bacterial strains by treating 10 bacterial strains from the Enterobacteriaceae family among which seven strains have no CPP permeation records with (KFF)₃K-FAM. Interestingly, when compared with non-optimized conditions, all 10 strains showed a marked increase in CPP permeation ranging between 20 and 90% efficiency. Although using strains within Enterobacteriaceae that are phylogenetically close, our results hinted on the possibility that with proper optimization of the abiotic factors, CPPs could be compatible with a broad range of bacterial strains. Our efforts suggest that CPP could serve as an effective alternative approach for mutant generation and for biomolecule delivery into novel or hard-to-transform bacteria.

Temperature and Sugar Feeding Effects on the Activity of a Laboratory Strain of Aedes aegypti

Aedes aegypti is an invasive mosquito species that is expected to expand its global distribution through climate change. As poikilotherms, mosquitoes are greatly affected by the temperature of the environment which can impact host-seeking, blood-feeding, and flight activity as well as survival and ability to transmit pathogens. However, an important aspect of mosquito biology on which the effect of temperature has not been investigated is water and sugar-feeding and how access to a sugar source might affect the insect's activity and survival under different thermal conditions. To close this knowledge gap, we relied on actometer experiments to study the activity of both female and male Ae. aegypti at 20 °C, 25 °C, and 30 °C, providing either water or 10% sucrose to the insects. We then measured the total carbohydrate contents of alive mosquitoes using the anthrone protocol. Survival was assessed and compared between all groups. Results from this study will inform on the thermal biology of Ae. aegypti mosquitoes and how access to sugar affects their activity.

Influence of Two Garlic-Derived Compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), on Growth and Mycotoxin Production by Fusarium Species In Vitro and in Stored Cereals

Two garlic-derived compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), were examined for their efficacy against mycotoxigenic Fusarium species (F. graminearum, F. langsethiae, F. verticillioides). The objectives were to assess the inhibitory effect of these compounds on growth and mycotoxin production in vitro, and in situ in artificially inoculated wheat, oats and maize with one isolate of each respectively, at different water activity (a_w) conditions when stored for up to 20 days at 25 °C. In vitro, 200 ppm of either PTS or PTSO reduced fungal growth by 50-100% and mycotoxin production by >90% depending on species, mycotoxin and a_w conditions on milled wheat, oats and maize respectively. PTS was generally more effective than PTSO. Deoxynivalenol (DON) and zearalenone (ZEN) were decreased by 50% with 80 ppm PTSO. One-hundred ppm of PTS reduced DON and ZEN production in wheat stored at 0.93 a_w for 20 days, although contamination was still above the legislative limits. Contrasting effects on T-2/HT-2 toxin contamination of oats was found depending on a_w, with PTS stimulating production under marginal conditions (0.93 a_w), but at 0.95 a_w effective control was achieved with 100 ppm. Treatment of stored maize inoculated with F. verticilliodies resulted in a stimulation of total fumonsins in most treatments. The potential use of such compounds for mycotoxin control in stored commodities is discussed.

Bottom-up control of geographic variation in insect herbivory on wild cotton (Gossypium hirsutum) by plant defenses and climate

PREMISE

The occurrence and amount of herbivory are shaped by bottom-up forces, primarily plant traits (e.g., defenses), and by abiotic factors. Addressing these concurrent effects in a spatial context has been useful in efforts to understand the mechanisms governing variation in plant-herbivore interactions. Still, few studies have evaluated the simultaneous influence of multiple sources of bottom-up variation on spatial variation in herbivory.

METHODS

We tested to what extent chemical (phenolics, production of terpenoid glands) and physical (pubescence) defensive plant traits and climatic factors are associated with variation in herbivory by leaf-chewing insects across populations of wild cotton (Gossypium hirsutum).

RESULTS

We found substantial population variation in cotton leaf defenses and insect leaf herbivory. Leaf pubescence, but not gossypol gland density or phenolic content, was significantly negatively associated with herbivory by leaf-chewing insects. In addition, there were direct effects of climate on defenses and herbivory, with leaf pubescence increasing toward drier conditions and leaf damage increasing toward wetter and cooler conditions. There was no evidence, however, of indirect effects (via plant defenses) of climate on herbivory.

CONCLUSIONS

These results suggest that spatial variation in insect herbivory on wild G. hirsutum is predominantly driven by concurrent and independent influences of population variation in leaf pubescence and climatic factors.

Where and when? How phenological patterns of armyworm moths (Lepidoptera: Noctuidae) change along a latitudinal gradient in Brazil

The phenological patterns exhibited by different organisms are known as adaptive responses to the cyclical environmental conditions. However, only a limited number of researches explore which factors are responsible for these phenological patterns in pest species. In the current study, abundance patterns were studied in the phenology of three Spodoptera Guenée, 1852 species, along the 29° latitudinal gradient in South America. The goal was to test whether widely distributed and abundant crop pest species would exhibit different phenological responses to seasonal meteorological variables and host plant availability. To test this, 13 light traps were set up in Brazil to collect adult Spodoptera samples at the time of the new moon, every month, from June 2015 to May 2016. The time of occurrence and intensity of the phenology were determined for each species, employing circular statistics. Both metrics revealed significant variations among the different species, as well as the factors associated with them. Latitude was found to affect the period of occurrence in Spodoptera cosmioides (Walker, 1858) and Spodoptera albula (Walker, 1857), whereas in Spodoptera frugiperda (J. E. Smith, 1797) its effect was evident only in the intensity of its phenology. Further, both meteorological variables and host plant availability in the sampling sites produced predictive models to account for the phenological patterns expressed. These findings suggest that different species of Spodoptera exhibit different adaptive strategies in their life cycles in response to environmental conditions, thus necessitating specific management practices regarding their seasonal population fluctuation.

Air pollution as an experimental probe of insect population dynamics

In Focus: Hunter, M. D., & Kozlov, M. V. (2019) The relative strengths of rapid and delayed density-dependence acting on a terrestrial herbivore change along a pollution gradient. Journal of Animal Ecology, 88, 665-676. Teasing apart the interactions between biotic and abiotic factors affecting animal population dynamics is a difficult task when based solely on the analysis of natural populations. Experimental manipulations of systems using microcosm studies can be powerful tools for probing such interactions, but microcosms are ultimately limited by their lack of complexity compared with nature. Hunter and Kozlov (2019) take a novel field-based experimental approach to studying abiotic influences on biotic interactions by quantifying how the presence of a pollutant source alters biotic processes driving populations of a forest leaf miner. They find that populations in proximity to a pollutant source show weaker direct density dependence and stronger delayed density dependence than more distant populations unaffected by pollution. These differences in density dependence cause higher equilibrium densities near the pollution source but surprisingly they do not alter leaf miner oscillatory dynamics. This creative study provides useful insight into how abiotic forces alter biotic population processes and how density dependence shapes the spatial dynamics of animal populations.

Effect of Temperature on Oviposition Behavior and Egg Load of Blow Flies (Diptera: Calliphoridae)

Making optimal oviposition decisions is especially important for female carrion colonizing insects whose larvae often depend on ephemeral resources. Optimal oviposition theory predicts that females should exhibit behaviors that will maximize the performance of their offspring. Oviposition can be influenced by a variety of factors, including temperature. The aim of this study was to investigate the effects of temperature on the oviposition behavior and egg load of two blow fly species native to southern Ontario: Phormia regina Meigen, and Lucilia sericata Meigen (Diptera: Calliphoridae). Using fetal pig carcasses as an oviposition substrate, we assessed the length of time until the first oviposition event, preferred oviposition sites, and the total number of eggs oviposited. For each of the two species, five different temperature treatments ranging from 15 to 35°C were used. Temperature influenced time to the first oviposition event, as well as the number of eggs deposited by L. sericata and P. regina. As temperature increased, oviposition occurred faster with more eggs deposited for these two species. Female P. regina, in particular, demonstrated a higher egg load with increasing temperature. Differences in optimal temperatures for reproduction, including egg load and oviposition, may be a mechanism driving seasonal temporal resource partitioning leading to species coexistence utilizing ephemeral resources.

Role of Arbuscular Mycorrhizal Fungi in Plant Growth Regulation: Implications in Abiotic Stress Tolerance

Abiotic stresses hamper plant growth and productivity. Climate change and agricultural malpractices like excessive use of fertilizers and pesticides have aggravated the effects of abiotic stresses on crop productivity and degraded the ecosystem. There is an urgent need for environment-friendly management techniques such as the use of arbuscular mycorrhizal fungi (AMF) for enhancing crop productivity. AMF are commonly known as bio-fertilizers. Moreover, it is widely believed that the inoculation of AMF provides tolerance to host plants against various stressful situations like heat, salinity, drought, metals, and extreme temperatures. AMF may both assist host plants in the up-regulation of tolerance mechanisms and prevent the down-regulation of key metabolic pathways. AMF, being natural root symbionts, provide essential plant inorganic nutrients to host plants, thereby improving growth and yield under unstressed and stressed regimes. The role of AMF as a bio-fertilizer can potentially strengthen plants' adaptability to changing environment. Thus, further research focusing on the AMF-mediated promotion of crop quality and productivity is needed. The present review provides a comprehensive up-to-date knowledge on AMF and their influence on host plants at various growth stages, their advantages and applications, and consequently the importance of the relationships of different plant nutrients with AMF.

Reproductive biology of the tiger pleco Panaqolus tankei (Loricariidae) in a lentic system of the Amazon Basin

This study presents the first information on the reproduction of the recently described tiger pleco Panaqolus tankei, from Lake Bolonha in the north-eastern Amazon Basin. This loricariid has a long reproductive period, fractionated spawning and low fecundity (on average, female gonads contained 37 oocytes), a total length (L_T ) at first maturity of 47.4 mm for females and 54.1 mm L_T for males. Correlation of the condition factor and gonado-somatic index with environmental variables suggests that turbidity favours P. tankei reproduction in this environment.

Prediction of Sporulation and Germination by the Spider Mite Pathogenic Fungus Neozygites floridana (Neozygitomycetes: Neozygitales: Neozygitaceae) Based on Temperature, Humidity and Time

Neozygites floridana is a pathogenic fungus and natural enemy of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), which is an important polyphagous plant pest. The aim of this study was to reveal and predict what combination of temperature, relative humidity (RH), and time that enables and promotes primary conidia production and capilliconidia formation in N. floridana (Brazilian isolate ESALQ 1420), in both a detached leaf assay mimicking climatic conditions in the leaf boundary layer and in a semi-field experiment. In the detached leaf assay, a significant number of conidia were produced at 90% RH but the highest total number of primary conidia and proportion of capilliconidia was found at 95 and 100% RH at 25 °C. Positive temperature and RH effects were observed and conidia production was highest in the 8 to 12 h interval. The semi-field experiment showed that for a >90% probability of N. floridana sporulation, a minimum of 6 h with RH >90% and 10 h with temperatures >21 °C, or 6 h with temperatures >21 °C and 15 h with RH >90% was needed. Our study identified suitable conditions for primary- and capilliconidia production in this Brazilian N. floridana isolate. This information provides an important base for building models of a Decision Support System (DSS) where this natural enemy may be used as a tool in Integrated Pest Management (IPM) and a base for developing in vivo production systems of N. floridana.

[Seasonal Succession of Phytoplankton Functional Groups and Their Driving Factors in the Siminghu Reservoir]

The succession of phytoplankton communities is affected by pure environmental factors as well as the interaction of various factors. Phytoplankton communities with eleven aquatic abiotic factors and four biotic factors were investigated in the Siminghu Reservoir, and the seasonal succession of phytoplankton FGs related to the biotic and abiotic factors was analyzed. The results suggested that a total of 22 phytoplankton functional groups were identified across the samples, and they were all affiliated with Chlorophyta and Bacillariophyta. An obvious seasonal succession was discovered by NMDS, which were present as D+Lo in summer, D+P+Lo in autumn and winter, and X2+P+MP in spring. In particular, we screened 10 functional groups with biomass significantly associated with the seasonal change in the phytoplankton community. A variance partitioning analysis (VPA) revealed that water temperature-zooplankton covariation and water temperature explained the variation in the phytoplankton functional groups throughout the year. A canonical correspondence analysis (CCA) showed that water temperature, transparency, nitrate nitrogen, and the biomass of zooplankton were the most critical factors determining the community dynamics of phytoplankton.

Responses of insect herbivores and their food plants to wind exposure and the importance of predation risk

Wind is an important abiotic factor that influences an array of biological processes, but it is rarely considered in studies on plant-herbivore interactions. Here, we tested whether wind exposure could directly or indirectly affect the performance of two insect herbivores, Plutella xylostella and Pieris brassicae, feeding on Brassica nigra plants. In a greenhouse study using a factorial design, B. nigra plants were exposed to different wind regimes generated by fans before and after caterpillars were introduced on plants in an attempt to separate the effects of direct and indirect wind exposure on herbivores. Wind exposure delayed flowering, decreased plant height and increased leaf concentrations of amino acids and glucosinolates. Plant-mediated effects of wind on herbivores, that is effects of exposure of plants to wind prior to herbivore feeding, were generally small. However, development time of both herbivores was extended and adult body mass of P. xylostella was reduced when they were directly exposed to wind. By contrast, wind-exposed adult P. brassicae butterflies were significantly larger, revealing a trade-off between development time and adult size. Based on these results, we conducted a behavioural experiment to study preference by an avian predator, the great tit (Parus major) for last instar P. brassicae caterpillars on plants that were exposed to either control (no wind) or wind (fan-exposed) treatments. Tits captured significantly more caterpillars on still than on wind-exposed plants. Our results suggest that P. brassicae caterpillars are able to perceive the abiotic environment and to trade off the costs of extended development time against the benefits of increased size depending on the perceived risk of predation mediated by wind exposure. Such adaptive phenotypic plasticity in insects has not yet been described in response to wind exposure.

Range Expansion of Tick Disease Vectors in North America: Implications for Spread of Tick-Borne Disease

Ticks are the major vectors of most disease-causing agents to humans, companion animals and wildlife. Moreover, ticks transmit a greater variety of pathogenic agents than any other blood-feeding arthropod. Ticks have been expanding their geographic ranges in recent decades largely due to climate change. Furthermore, tick populations in many areas of their past and even newly established localities have increased in abundance. These dynamic changes present new and increasing severe public health threats to humans, livestock and companion animals in areas where they were previously unknown or were considered to be of minor importance. Here in this review, the geographic status of four representative tick species are discussed in relation to these public health concerns, namely, the American dog tick, Dermacentor variabilis, the lone star tick, Amblyomma americanum, the Gulf Coast Tick, Amblyomma maculatum and the black-legged tick, Ixodes scapularis. Both biotic and abiotic factors that may influence future range expansion and successful colony formation in new habitats are discussed.

Environmental and Host Effects on Skin Bacterial Community Composition in Panamanian Frogs

Research on the amphibian skin microbiota has focused on identifying bacterial taxa that deter a pathogenic chytrid fungus, and on describing patterns of microbiota variation. However, it remains unclear how environmental variation affects amphibian skin bacterial communities, and whether the overall functional diversity of the amphibian skin microbiota is associated to such variation. We sampled skin microbial communities from one dendrobatoid frog species across an environmental gradient along the Panama Canal, and from three dendrobatoid frog species before and after the onset of the wet season in one site. We found frog skin microbial alpha diversity to be highest in frogs from sites with low soil pH, but no clear effect of the onset of the wet season. However, we found frog skin microbial community structure to be affected by soil pH and the onset of the wet season, which also resulted in a decrease in between-sample variation. Across the sampled frog species, bacterial functional groups changed with the onset of the wet season, with certain bacterial functional groups entirely disappearing and others differing in their relative abundances. In particular, we found the proportion of Bd-inhibitory bacteria to correlate with mean soil pH, and to increase in two of the frog species with the onset of the wet season. Taken together, our results suggest that structure and predicted function of amphibian bacterial skin communities may be influenced by environmental variables such as pH and precipitation, site effects, and host effects.

Effects of lightning on trees: A predictive model based on in situ electrical resistivity

The effects of lightning on trees range from catastrophic death to the absence of observable damage. Such differences may be predictable among tree species, and more generally among plant life history strategies and growth forms. We used field‐collected electrical resistivity data in temperate and tropical forests to model how the distribution of power from a lightning discharge varies with tree size and identity, and with the presence of lianas. Estimated heating density (heat generated per volume of tree tissue) and maximum power (maximum rate of heating) from a standardized lightning discharge differed 300% among tree species. Tree size and morphology also were important; the heating density of a hypothetical 10 m tall Alseis blackiana was 49 times greater than for a 30 m tall conspecific, and 127 times greater than for a 30 m tall Dipteryx panamensis. Lianas may protect trees from lightning by conducting electric current; estimated heating and maximum power were reduced by 60% (±7.1%) for trees with one liana and by 87% (±4.0%) for trees with three lianas. This study provides the first quantitative mechanism describing how differences among trees can influence lightning–tree interactions, and how lianas can serve as natural lightning rods for trees.

How Environmental Factors Affect the Production of Guanidine Alkaloids by the Mediterranean Sponge Crambe crambe

Most marine sponges are known to produce a large array of low molecular-weight metabolites which have applications in the pharmaceutical industry. The production of so-called specialized metabolites may be closely related to environmental factors. In this context, assessing the contribution of factors like temperature, nutrients or light to the metabolomes of sponges provides relevant insights into their chemical ecology as well as the supply issue of natural sponge products. The sponge Crambe crambe was chosen as a model due to its high content of specialized metabolites belonging to polycyclic guanidine alkaloids (PGA). First results were obtained with field data of both wild and farmed specimens collected in two seasons and geographic areas of the North-Western Mediterranean. Then, further insights into factors responsible for changes in the metabolism were gained with sponges cultivated under controlled conditions in an aquarium. Comparative metabolomics showed a clear influence of the seasons and to a lesser extent of the geography while no effect of depth or farming was observed. Interestingly, sponge farming did not limit the production of PGA, while ex situ experiments did not show significant effects of several abiotic factors on the specialized metabolome at a one-month time scale. Some hypotheses were finally proposed to explain the very limited variations of PGA in C. crambe placed under different environmental conditions.