Assessment of perennial ryegrass (Lolium perenne L.) genotypes under Latvia agro-ecological conditions

Within the frame of the Nordic/Baltic public-private partnership ’PPP for pre-breeding in perennial ryegrass’ various activities were performed, including assessment of L. perenne (Lp) genotypes under agro-ecological conditions of Latvia. This article summarizes the data obtained in two harvest years for 19 intermediate tetraploid (4x) Lp genotypes. In order to compare the results obtained in ryegrass with performance of grass interspecies hybrids (Fl), which become especially relevant in the recent years, two varieties, developed in Latvia – Lolium × boucheanum Kunth. ‘Saikava’ and × Festulolium ‘Vizule’ were included in the experiment. Various scores were performed, including evaluation of regrowth, intensity of culm development, sward cover, crown rust (Puccinia coronata) susceptibility, etc. The dry matter yield (DMY) and fodder quality were also determined. It can be concluded that the genotypes showed relatively good results in the first two harvest years. Wintering conditions were favourable. Despite the intensified drought and heat in the 1st ley year, relatively high DMY, which ranged from 9.30 to 12.15 t ha-1, for Lp were harvested in three cuts. In the 2nd ley year, under more favourable humidity conditions, Lp in four cuts provided similar DMY, which ranged from 8.81 to 11.50 t ha-1. If we compare the average DMY of Lp and Fl genotypes, it can be concluded that in the first two harvest years no significant differences were found, the average DMY was 10.30 and 10.64 t ha-1, respectively. No significant differences were found between Lp and Fl in terms of forage quality.

Spatio-temporal variation in the wintering associations of an alpine bird

Many animals make behavioural changes to cope with winter conditions, being gregariousness a common strategy. Several factors have been invoked to explain why gregariousness may evolve during winter, with individuals coming together and separating as they trade off the different costs and benefits of living in groups. These trade-offs may, however, change over space and time as a response to varying environmental conditions. Despite its importance, little is known about the factors triggering gregarious behaviour during winter and its change in response to variation in weather conditions is poorly documented. Here, we aimed at quantifying large-scale patterns in wintering associations over 23 years of the white-winged snowfinch Montifringilla nivalis nivalis . We found that individuals gather in larger groups at sites with harsh wintering conditions. Individuals at colder sites reunite later and separate earlier in the season than at warmer sites. However, the magnitude and phenology of wintering associations are ruled by changes in weather conditions. When the temperature increased or the levels of precipitation decreased, group size substantially decreased, and individuals stayed united in groups for a shorter time. These results shed light on factors driving gregariousness and points to shifting winter climate as an important factor influencing this behaviour.

Lithium chloride outperformed oxalic acid sublimation in a preliminary experiment for Varroa mite control in pre-wintering honey bee colonies

Since lithium salts were demonstrated to be very effective for the potential control of Varroa destructor, a highly detrimental parasite of honey bee (Apis mellifera), no studies have been reported on their comparison with any commonly used varroicides in commercial bee colonies. In this study we compared the effectiveness of lithium chloride to that of oxalic acid, a widely used miticide. The results of the present study confirm that lithium has superior efficacy to oxalic acid sublimation both as a main or a supplementary pre-wintering treatment at moderate infestation levels, restricted to certain pre-wintering conditions. Considering its easy implementation in apicultural practice and its twofold mode of action, trickling would be the preferred way of administration after the use of lithium salts as varroicides is authorised.

Bioecological features of coccinellide in the southern Kashkadarya province, Uzbekistan

This research was conducted in 2019-2020 in the northern and southern administrative districts of the southern Kashkadarya province of Uzbekistan. This study on the distribution of coccinellides in agrobiocenoses has been conducted at different experimental periods. In the agrobiocenoses of Kashkadarya province, 5 subspecies of coccinellides (Scymninae, Chilocorinae, Coccidulinae, Epilachninae, and Coccinellinae), 8 tribes, and 31 species belonging to 22 genera were found. Experiments have shown that species belonging to the genera Chilocorus (Leach, 1875) are relatively rare species and are not considered specific species for cotton agrocenosis. Coccinella septempunctata was observed as the most common species. The eggs of Coccinella septempunctata were studied separately in this research. Wintering conditions in mountainous areas were also considered and particular attention was paid to the beneficial entomophagous species of coccinellides.

Influence of ice crust on frost resistance and survival of winter wheat in the Steppe of Ukraine

The features of the effect both separately and together of lapped ice crust and low temperatures on winter wheat plants was highlighted. During the research period (2017–2019), the plants of the Mudrist Odeska variety which were damaged by low temperature and ice crust began to ear by 3–6 days later than undamaged ones. It was found that under unfavorable wintering conditions, in particular in plots without snow, the plant density per area unit and productive tillering, as well as grain productivity of the crop, largely depended on the degree of winter hardiness of plants. After growing of winter wheat which was frozen in laboratory conditions (without lapped ice crust) at a temperature of -15 °C, all plants survived, when the temperature dropped to -18 °C, 16.3 % of plants died. A further drop in temperature to -21 °C caused the loss of 81.7 % of plants. Against the background of artificially created lapped ice crust, the tillering nodes of the winter wheat plant were more damaged and, accordingly, the survival rate of plants decreased compared to variants without lapped ice crust, and at a freezing temperature of -15 °C its indicators were 69.8–92.0 %; at a temperature of -18 °C – 12.6–74.5 % depending on the thickness of the ice crust. When the cryogenic load increased to -21 °C, winter wheat died under the ice crust. During the growing season, in variants of mineral nutrition with a dose of N60P60K60, the death of winter wheat shoots compared with the non-fertilized control variant was less by 4.9–23.1 %. The dynamics of the soluble carbohydrate content in the tillering nodes indicates that at the resumption of spring vegetation the minimum consumption of carbohydrates by plants (30.8% of autumn reserves) was observed in variants with N60P60K60 fertilization. In the plots without snow cover under the lapped ice crust, carbohydrates were intensively consumed by plants, as a result, their amount in the tillering nodes during the winter period decreased on non-fertilized and fertilized variants by 58.5 and 61.2 %, respectively. Key words: winter wheat, frost resistance, mineral fertilizers, ice crust, productivity, survival.

The degree of ripening of the grapevine in the varieties of selection of National Scientific Centre ‟Institute of viticulture and wine-making after V.YE. Tairovˮ in the conditions of the northern part of the Forest-steppe of Ukraine

Strong growth of shoots and ripening of grape fruits do not give grounds for claiming that the variety is in accordance with the climatic conditions of a certain area. Only a well-ripe vine can withstand severe winter conditions. The purpose of the study is to determine the degree of maturation of the vine in grape varieties of Odessa breeding grown in the northern part of the Forest-steppe, and to identify among them the most prepared for wintering conditions in the area. The degree of maturation of the vine was determined during 2018–2019 in the autumn before the cover of grape plants by the method of primary fluorescence using a microscope MBS-2 with fluorescent illuminator OI-18 and by the method of N. Matuzok. Studies have shown that the degree of ripening of the grapevine depends on the weather conditions during the growing season and varietal characteristics of the plants. Weather conditions during the years of study contributed to the good maturation of the shoots of grapes of all varieties except Kometa and Zahadka. The first had a characteristic brown color of the mature bark along the entire length of the shoot. When bending the vine in its upper part of the characteristic cracking of the bark was not in the varieties Kometa, Zahadka, Yarylo and Muskat odeskyi. The highest degree of ripening of shoot tissues was noted in the lower zone of the vine in the Aromatnyi, Kardyshakh, Kishmish tayirovskij. In the middle zone of shoots, the highest degree of maturation of the felema was found in the variety Kardyshakh, and in the upper part of the shoot, in the variety Aromatnyi. The highest conditional coefficient of maturation (Kv) of the tissues of the vine in the fifth internode is defined in the varieties Aromatnyi and Kyshmysh tairovskyi (0.90), the mean in the variety Kardyshakh (0.88), and the lowest in the variety Kometa (0.56). Based on the data obtained from the results of complex studies, it was found that the varieties Aromatnyi, Kyshmysh tairovskyi and Kardyshakh are the most prepared for wintering in the northern part of the Forest-steppe.

Modelling the Bioclimatic Niche and Distribution of the Steppe Mouse, Mus Spicilegus (Rodentia, Muridae), in Ukraine

The Steppe mouse, Mus spicilegus, is endemic to Europe and found to be expanding its home range in recent years. In Ukraine there are indications a north- and eastwards expansion and/or reestablishment of M. spicilegus. We suggest that climatic conditions may be the primary factors that foster or limit the range expansion of M. spicilegus in Eastern Europe. Our objective was to complement the knowledge about the distribution of the species with an estimation of the potential distribution of the species in Ukraine using known occurrence sites (in Ukraine and neighbouring areas) and environmental variables in an ecological niche modelling algorithm. After accounting for sampling bias and spatial autocorrelation, we retained 73 occurrence records. The algorithm used in this paper, Maxent (Phillips et al., 2006), is a machine learning algorithm and only needs presence data, besides the environmental layers. Using this approach, we have highlighted the importance and significance of a number of bioclimatic variables, particularly those characterizing wintering conditions, under which higher mean temperatures enhance habitat suitability, whereas increased precipitation leads to an opposite effect. The broadly northwards shift of the home range of the species in Ukraine could generally be due to the increasing (since the 1980s) mean temperature of the winter season. We expect this expansion process will continue together with the changing climate and new records of locations of the species may be used for monitoring such change.

Reasons for the number of insects decrease of the Samara Region (on the example of leaf beetle populations)

The survival mechanisms of leaf beetles (as typical phytophagous insects, surrounded by a corrosive environment: unstable, rapidly changing climate, decreasing forage, direct action of predators, ecto- and endoparasites, parasitoids, pathogens helminthiasis and entomophtorous, other pathogenic organisms) were studied during 1974-2016 in the Samara Region. 25 background species of chrysomelid beetles (approximately 240 individuals) were used as model objects. In addition to the natural fluctuations of the insect population, 21 causes of sudden increase in the number of local populations of leaf beetles were revealed, as a result of the influence of negative environmental agents, including abiotic (8), biotic (12) and anthropic (1 reason). From 5% to 90% of the leaf beetles population die as a result of unfavorable wintering conditions, sharp fluctuations in temperature and humidity, wind and precipitation; 2 reasons (concerning the resources of the forage base), 2 reasons (caused by the imbalance of the age and sexual structure of the population and therefore low reproductive potential), 2 reasons (determined by the fierce competition of insects and larval cannibalism) and 6 reasons (associated with the influence of predators, parasites and pathogens) are able to withdraw from 2% to 96% of the livestock (eggs, larvae, pupae and adults) of the population. It is concluded that many agents affects the number of insects.

Dispersal-dependent juvenile survival in a sexually dimorphic long-lived bird, the Greater Flamingo Phoenicopterus roseus

The viability and dynamics of spatially structured populations depend critically upon dispersal behaviour. Yet, in long lived species with delayed maturity, the fitness consequences of post-fledging dispersal, dispersal from the birthplace after independence and before first breeding attempt, are poorly understood although it is a critical determinant of natal dispersal.We aimed at estimating sex-specific variations of juvenile survival in a long-lived bird species with sexual size dimorphism, the greater flamingo, as a function of post fledging dispersal destination. Using capture-recapture models, we estimated the survivorship of flamingos ringed in the Camargue (south of France) and wintering in the Mediterranean.Dispersal probability from France was > 0.66 with important annual variations in preferred dispersal destinations. First-year survival increased along the winter temperature gradient with estimates below 0.50 ± 0.07 in France and above 0.60 ± 0.07 in African wetlands. The survival of flamingos wintering in France dropped by 30–50 % depending on sex between fall and spring of their first year.In African sites and in Italy, there was no detectable difference of survival between sexes suggesting favorable wintering conditions. Body condition at fledging did not explain variations in first-fall survival within genders. Males wintering in France had a better survival than females.These results show that sex and post-fledging dispersal destination affect juvenile survival, support the energetic hypothesis predicting an advantage of large body size to cope with cold temperatures and the competition hypothesis, and suggest the existence of sex-specific post fledging dispersal tactics.