Ant-aphid mutualism is considered to be a beneficial association for the individuals concerned. The population and fitness of aphids affected by ant attendance and the outcome of this relationship affects the host plant of the aphid. The main hypothesis of the current study is that ant tending decreases aphid developmental time and/or increases reproduction per capita, which seriously reduces host plant fitness. The effect of attendance by the ant Tapinoma erraticum (Latreille, 1798) (Hymenoptera: Formicidae) on population growth and duration of different developmental stages of Aphis gossypii Glover (Hemiptera: Aphididae) were determined along with the consequences for the fitness of the host plant of the aphid, Vicia faba L., in greenhouse conditions. The initial aphid density was manipulated in order to study aphid performance due to density-dependent changes in ant attendance. The population growth rate of ant attended aphids was more than that of unattended aphids. However, the ratio of 1st-2nd nymphs to adults in aphid populations attended by ants was lower. The yields of bean plants on which the aphids were attended by ants were significantly greater than those of unattended plants. This study indicates that ants not only increase aphid fitness in terms of their population growth rate, but also benefit the host plant., Afsane Hosseini, Mojtaba Hosseini, Noboru Katayama, Mohsen Mehrparvar., and Obsahuje bibliografii
The factors that affect the local distribution of the invasive Harmonia axyridis are not yet completely resolved. Hypotheses predicting positive and independent effects of prey abundance and degree of urbanization on the adult abundance of this species in Central Europe were tested. Populations of H. axyridis were sampled in a period when it was most abundant, by sweeping lime trees (Tilia spp.) at 28 sites along a 20 km transect across urban (western Prague) and surrounding rural areas. The sites differed in aphid abundance (number of Eucallipterus tiliae per 100 sweeps) and degree of urbanization (percentage of the surrounding area within a 500 m radius covered by impervious human constructions). Multiple linear regression analysis of log-transformed data revealed that abundance of H. axyridis (number of adults per 100 sweeps) increased significantly with both aphid abundance (P = 0.015) and urbanization (P = 0.045). The positive relationship between degree of urbanization and abundance of H. axyridis was thus not a side effect of variation in aphid abundance, which was also greater in urban than rural areas. The effect of urbanization might constrict the habitat available to H. axyridis and force this species to aggregate in urban green "refugia". These results point to a plurality of factors that determine coccinellid abundance at natural sites.
At a three-leaf stage, two Fe treatments [0 mg kg-1 (Fe-) and 20 mg.kg-1 (Fe+) in the form of FeCl3] were used in the soil of the pot and then two concentrations of α-ketoglutaric acid [0 mg L-1 (A-) and 50 mg L-1 (A+)] were sprayed to the rice plants of Meixiangzhan and Yuxiangyouzhan cultivars. We showed that seedlings exhibited an increased length and fresh and dry mass of shoots and roots with treatments Fe+A- and Fe-A+, as well as the Fe content increased greatly. Both treatments increased the morphological characteristic values of roots and promoted photosynthesis. Interestingly, Fe+A+ notably affected the photosynthesis of fragrant rice seedlings; however, it exerted no significant differences on other parameters. Overall, Fe and α-ketoglutaric acid had the potential for improving the growth of fragrant rice seedlings. The interaction between Fe and α-ketoglutaric acid regulated photosynthesis in seedling leaves, which provided evidence for further improvement of rice cultivation.
To investigate the influence of beer consumption on levels of homocysteine (HCY), vitamin B6, B12, folic acid (FA), dimethylglycine (DMG), betaine (BET) and other selected markers. One hundred and sixteen male volunteers were enrolled in the study. A one-month period of alcohol abstinence was followed by a one month when participants drank 830 ml of alcoholic beer every day. After that phase, one month of alcohol abstinence followed. At the beginning and after every phase, blood samples were taken and analysed. Ninety-three participants completed the study. After the phase of alcohol consumption, uric acid (UA) (p<0.0001), antioxidative capacity (AOC) (p=0.02), superoxide dismutase (SOD) (0.025), glutathione reductase (GRH) (0.0001), total cholesterol (p<0.0001), HDL-cholesterol (p<0.0001), Apolipoprotein-AI (ApoAI) (p<0.0001), LDL-cholesterol (p<0.039) and Apolipoprotein B (ApoB) (p<0.009) increased, while vitamin B12 (p=0.0001) and fibrinogen (p<0.0001) decreased. Other tested parameters (DMG, BET, vitamin B6 and FA) did not show any significant changes. UA changes and changes in AOC were statistically significantly correlated (r=0.52, p<0.0001). HCY, DMG and BET levels did not show any statistically significant changes after beer consumption, whereas some markers of redox metabolism increased (UA, AOC, SOD and GRH). A statistically significant correlation denotes the dependence of UA and AOC changes in connection with beer consumption.
Lake Śniardwy is the largest among more than 7000 Polish lakes. So far, it has not been a subject of detailed investigations concerning long-term changes in water temperature or ice regime. A considerable change in thermal and ice conditions has been observed in the period 1972–2019. Mean annual water temperature increased by 0.44°C dec–1 on average, and was higher than an increase in air temperature (0.33°C dec–1). In the monthly cycle, the most dynamic changes occurred in April (0.77°C dec–1). In the case of ice cover, it appeared increasingly later (5.3 days dec–1), and disappeared earlier (3.0 days dec–1). The thickness of ice cover also decreased (2.4 cm dec–1). Statistical analysis by means of a Pettitt test showed that the critical moment for the transformations of the thermal and ice regime was the end of the 1980’s. In addition to the obvious relations with air temperature for both characteristics, it was evidenced that the occurrence of ice cover depended on wind speed and snow cover. The recorded changes in the case of Lake Śniardwy are considered unfavourable, and their consequences will affect the course of physical, chemical, and biological processes in the largest lake in Poland.
Large debris transported by flood affects scour features at bridge piers and increases the risks of structural failure. Geometric characteristics of the debris and the relative position of the pier with respect to the river bank are important parameters for the scour process. The interaction between the water flow and debris accumulation increases the shear stress, turbulence and consequently enhances the scour depth at the pier. This paper aims at analyzing such effects on scour evolution at bridge piers. To this end, two series of tests were carried out under clear water condition with different debris geometries and percentage blockage ratios. Experimental evidences showed that the pier position only influences scour evolution and equilibrium morphology for low water depths. Conversely, its effect becomes negligible for scour at bridge piers with debris accumulation and higher water depths. Useful practical relationships have been derived, with satisfactory prediction capability of the scour evolution for all the tested configurations.
Ectoparasites are an important factor in bat health due to emergent diseases and their associated threats to global public health. The diverse foraging habits of bats expose them to different surfaces which may influence ectoparasite infestations. In spite of these, most studies often overlook dietary specialisations when observing ectoparasite loads. The present paper quantitatively investigates whether foraging strategies as well as other host characteristics (sex, age, trunk and patagial area) influence ectoparasite (nycteribiids and mites) loads of bats. Ectoparasite counts and morphometric data were taken from mist net captures of bats. We then developed and compared models for modeling bat ectoparasite abundance under various distributions using generalised linear models. The negative binomial distribution consistently proved to be adequate for modeling mite, nycteribiid and total ectoparasite abundance based on information-theoretic approaches. Generally, females and frugivores had higher ectoparasite loads conditional on bat sex and diet, respectively. Contrary to nycteribiid abundance, mite abundance was positively related to patagial area. Thus, our findings suggest that dietary guild, sex and patagia of hosts (as well as age-nycteribiid abundance) are significant determinants of ectoparasite abundance., Albert Luguterah, Eric Adjei Lawer., and Obsahuje bibliografii
The effects of different light-emitting diode (LED) lights on saffron growth and photosynthetic characteristic were explored. Physiological mechanisms were explained by chlorophyll a fluorescence transient curves (OJIP) and JIP-test parameters. A decrease in the red to blue light ratio resulted in negative effects, particularly for monochromatic blue (B) LED light; saffron seedlings showed reduced chlorophyll accumulation, inhibited leaf elongation, and decreased photosynthetic performance. In the OJIP curve, the higher positive K-band observed for B LED light indicated that oxygen-evolving complex activation significantly decreased. B LED light inhibited the electron transport between primary quinone acceptor and secondary quinone acceptor as well as the existence of reducing plastoquinone centers, and increased energy dissipation of reaction centers. Otherwise, the red to blue light ratio of 2:1 had a positive effect on saffron cultivation, resulting in the longest leaf lengths, highest chlorophyll content, and photosynthetic characteristics. This study provides theoretical guidance for saffron agricultural practices.
Anticipating warming related to climate change, commercial mango plantations in China have been shifting from lower to higher elevations. Such a practice may expose mangoes to climatic conditions that could affect photosynthesis. Photosynthesis research on mango has previously examined mature plantations but exploring adequate functions before the time of fruit production is necessary for later crop success. Therefore, we established two main commercial mango cultivars, Tainong No. 1 and Jinhuang, at 450 m and 1,050 m and examined their photosynthetic performance. Our results showed that photosynthetic capacity parameters, including maximum photosynthetic rate, apparent quantum yield, maximum carboxylation rate, and photosynthetic electron transport rate, were significantly different between cultivars due to elevation and positively correlated with leaf nitrogen per area. Moreover, the seasonal gas exchange of the two cultivars showed variations due to elevation, particularly during the warmer seasons. Therefore, elevation affects the photosynthetic performance of these mango cultivars.
The presence of gravel in soils modifies the porosity, pore connectivity and pore size distribution in the soil matrix as well as the soil matrix-gravel interfaces. The aim of the present study is to investigate the effect of relative volume of gravel in samples with gravel mass fractions of 5,10, 20 wt% and varying bulk densities (1.3, 1.45, 1.55, 1.60, 1.65 g cm–3) on (i) total porosity, field capacity, plant available water holding capacity, (ii) pore size distribution and (iii) thermal capacity of repacked sandy and silty soils. The focus of the study was to determine if laboratory measured soil water retention curves considering (i), (ii), and (iii) can be predicted by a gravel-based weighting factor, Rv, considering comprehensive significance tests. The sand-gravel mixtures show a decrease in the volume fractions of macropores and wide cores pores with an increase in the gravel contents, while the silt-gravel mixtures show an opposite trend. The root mean square errors (RMSE) between measured and fitted volumetric water contents, θ, between 0.006 and 0.0352 and between 0.002 and 0.004 for Rv-weighted volumetric water contents indicate that the van Genuchten-based Peters-Durner- Iden (PDI) model is appropriate for fitting. The soil water retention curves with mass gravel contents of up to 10 wt% for silt and 20 wt% for sand can be well predicted by weighting factors (relative volume of rock fragments) in the range between 0.045 and 0.058 for silt, and between 0.112 and 0.119 for sand. The results also indicate a decrease in the Rv-weighted saturated, cvsat, and dry, cvdry, thermal capacity with an increase in the gravel contents for both soils. Further investigations are needed to examine if and whether measured sand- and silt-gravel mixtures with mass gravel contents below 10 % or rather 20 % can be predicted with a weighting factor.