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The numbers per tiller (abundance) and per unit area of ground (population density) of the dominant cereal aphids in winter wheat crops, Sitobion avenae (Fabricius) and Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) were recorded from 2000–2015. The results were used to test the hypothesis that at the population peak and 4 weeks previously, the population density of aphids in winter wheat crops (Triticum aestivum L., Poaceae) is uniformly distributed with respect to surface area and, as a result, their abundance is high in sparse stands (SPA) where the colonizing aphids are scattered among a small number of tillers (ca. 80 m−2), and low in dense stands (DEN) where they are scattered among a larger number of tillers (ca. 440 m−2). This prediction was verified for S. avenae, the population density of which did not significantly differ between SPA and DEN stands throughout this period. This species feeds mainly on the ears, whose nutritional quality for aphids varies little with crop density and during the course of ripening. In contrast and contrary to our prediction, the population density of M. dirhodum increased throughout this period more rapidly in SPA than in DEN stands. This species lives on leaves whose quality is better and remain present for longer during the course of ripening of the crop in SPA than DEN stands. The abundance of both species was higher in SPA than in DEN stands. Greater direct damage to cereal crops can be expected when using technologies and cultivars of winter wheat that need to be planted sparsely. [ABSTRACT FROM AUTHOR]

Using seventeen-year records of daily light trap catches of predatory Neuroptera (Chrysopidae, 13 species) and Coleoptera (Coccinellidae, 10 species), and of phytophagous Lepidoptera (Noctuidae, 79 species) we tested a hypothesis predicting that the range of annual fluctuations of catch size is greater in aphidophages, whose diet occurs irregularly and locally, than in phytophages, whose diet is available regularly and abundantly. The ranges of fluctuations of annual catches measured as the coefficient of variance (standard deviation expressed as a percentage of the average) of detrended annual catches were significantly greater in Chrysopidae (84 ± 7.1%) and Coccinellidae (121 ± 14.0%) than in Noctuidae (66 ± 2.6%). The difference between aphidophages and phytophages remained when we tested differences between the former and the samples of Noctuidae consisting only of those species whose characteristics (abundance, length and timing of flight period, number of generations per season, overwintering stage) were the same as in aphidophages. Similarly, no differences were found between sets of Noctuidae species that have characteristics (abundance, voltinism, period of flight activity) similar to aphidophages and sets of Noctuidae species that have contrary characteristics. Flight abilities of aphidophages are smaller than those of Noctuidae. As a result of this difference a light trap collects populations of aphidophages from a smaller area than populations of Noctuidae. Thus the extent of fluctuations of catch size of aphidophagous and phytophagous species is influenced both by annual differences in food availability and by differences in size of the area from which the individuals assembling to the light source are recruited. [ABSTRACT FROM AUTHOR]

The current climate warming is associated with the development of a second generation in populations of species such as Pyrrhocoris apterus (L.) (Heteroptera: Pyrrhocoridae), which, in Central Europe, were univoltine in the 1980s. Females of the fi rst generation that develop in spring either enter diapause immediately following the adult moult or after a period of oviposition that gives rise to a second generation. In 2005-2010, in overwintering populations, 3 ± 0.6% of females were fertilized. We explored the possibility that the females that overwintered in a fertilized state were those that had oviposited in the previous season. To test this hypothesis, we reared females of the fi rst generation that moulted to the adult stage in June-August under natural conditions. For these females, we recorded oviposition, mortality and overwintering in the fertilized state. In 2004-2007, the majority (78%) of the fi rst-generation females that oviposited in summer also died before winter and the rest entered dormancy and overwintered. Most of the overwintering females that had laid eggs before overwintering were fertilized. However, the majority (63%) of females that overwintered in the fertilized state had not laid eggs in the previous season; they only copulated and stored the sperm until the next spring. The presence of fertilized females in a hibernating population thus indicates pre-winter sexual activity but not the percentage of fi rst-generation females that oviposit before overwintering. [ABSTRACT FROM AUTHOR]

The relationship between the number of cereal aphids in flight (recorded by a national grid of suction traps in the Czech Republic) and their occurrence on winter wheat (in Prague) was established between 1999–2015. The flight of all the species was bimodal. Except for Rhopalosiphum padi, whose flight activity peaked in autumn, > 80% of individuals were trapped during April to mid-August. The species frequency was different between the winter wheat and aerial populations. R. padi, the dominant species in the trap catches, formed a small proportion of the aphids on the winter wheat, while Sitobion avenae and Metopolophium dirhodum, which were underrepresented in the suction traps, alternately dominated the populations on the wheat. The aphid abundance in the wheat stands was correlated with the suction trap catches in the “spring” peak (April to mid-August), and the maximum flight activity occurred 4–10 days after the peak in the number of aphids on the wheat. In contrast, the prediction of the aphid abundance in the wheat stands using the total suction trap catches until the 15th of June (the final date for the application of crop protection actions) was reliable only for M. dirhodum. Its maximum abundance on the wheat exceeded 40 aphids per tiller if the total suction trap catch until the 15th of June was ≥ 60 individuals per trap. The prediction of R. padi and S. avenae abundance using the suction trap catches was not reliable. [ABSTRACT FROM AUTHOR]

Preferences of seed predators may be an important factor that introduces bias in the results of seed predation studies. In this paper, we report on the experimentally established preferences of carabid beetles for seeds of herbaceous plants. The standard arrangement of 28 species of seeds from 13 families was offered to 37 species of carabids belonging to 5 tribes. The overall consumption was affected by the body mass more than by the body length and showed a quadratic relationship with the dry body mass of the carabid. The number of preferred species of seeds varied from 1 to 16, and in unspecialized species the ordered standardized consumptions formed an almost straight line with negative slope, while in specialized to highly specialized species the standardized consumption exponentially declined with increasing order of species. The most preferred seeds were Taraxacum officinale, Capsella bursa-pastoris, Tripleurospermum inodorum and Descurainia sophia, which were preferred by 28, 20, 19 and 19 species of carabids, respectively, while Consolida regalis, Arctia lappa and Bidens tripartita were not preferred by any of the studied carabids. We pinpoint that choice for a model seed species for a seed predation experiment in the field shall reflect the attractiveness of the seed for predators as seed identity may bring bias in the results. [ABSTRACT FROM AUTHOR]

The mating behaviour of Pyrrhocoris apterus in the laboratory is well studied, but little is known about it under natural conditions. In natural populations in Central Europe, overwintered adults start copulating in March and continue until their death. Caged females, kept under natural conditions in the permanent presence of males, copulated repeatedly. Their mating activity increased sharply until early April, then very slowly until the end of June and then declined as the females die-off. Half of copulations were short (< 5 h) and only 9% were longer than 1 day. By contrast, in natural populations, mating activity (percentage of individuals involved in copula) reached its maximum in April and then decreased until early July, when the overwintered adults die. The decline in mating frequency (percentage of adults involved in copula) was associated with a decrease in the availability of receptive females towards the end of the mating period. For a female, repeated copulation is necessary because sperm is nearly depleted after insemination of 3-5 egg batches. [ABSTRACT FROM AUTHOR]

Seeds of many species of plants may survive for a long time in the soil and germinate when brought to the surface, but whether they are subsequently eaten by seed predators is unknown. We examined the preferences of three species of carabids (Coleoptera: Carabidae) for 25 species of seeds and determined the difference in palatability between freshly dispersed and those buried for six years. The stability of their preferences was tested using a collection of seeds of different species, each of which was offered fresh or after being buried. Carabid beetles readily accepted previously buried seeds as food. In total, Pseudoophonus rufipes and Amara littorea ate more fresh seeds than previously buried seeds, while the opposite was true for Harpalus affinis. The seeds of some species were even more attractive to carabids after burial than in the fresh state. For all the species of carabids tested, the diet breadth was similar when the beetles were fed fresh or buried seeds, but the preferences for fresh and buried seed of particular species were correlated only in P. rufipes and A. littorea. We measured the seed characteristics (mass and viability) likely to be associated with the loss of attractiveness to carabids during burial. The change in carabid consumption was not related to changes in any of these characteristics. This fi nding indicates that factors responsible for variation in seed acceptability are complex. This study provides the fi rst conclusive evidence that invertebrate seed predators will feed on seeds from seed banks, although they prefer fresh seeds. [ABSTRACT FROM AUTHOR]

To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profiles) were compared in terms of their size (area under the seasonal profile curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profiles varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profiles revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this fl exibility is an important factor in its invasive success. [ABSTRACT FROM AUTHOR]

The mating behaviour of Pyrrhocoris apterus in the laboratory is well studied, but little is known about it under natural conditions. In natural populations in Central Europe, overwintered adults start copulating in March and continue until their death. Caged females, kept under natural conditions in the permanent presence of males, copulated repeatedly. Their mating activity increased sharply until early April, then very slowly until the end of June and then declined as the females die-off. Half of copulations were short (< 5 h) and only 9% were longer than 1 day. By contrast, in natural populations, mating activity (percentage of individuals involved in copula) reached its maximum in April and then decreased until early July, when the overwintered adults die. The decline in mating frequency (percentage of adults involved in copula) was associated with a decrease in the availability of receptive females towards the end of the mating period. For a female, repeated copulation is necessary because sperm is nearly depleted after insemination of 3-5 egg batches. [ABSTRACT FROM AUTHOR]

Seeds of many species of plants may survive for a long time in the soil and germinate when brought to the surface, but whether they are subsequently eaten by seed predators is unknown. We examined the preferences of three species of carabids (Coleoptera: Carabidae) for 25 species of seeds and determined the difference in palatability between freshly dispersed and those buried for six years. The stability of their preferences was tested using a collection of seeds of different species, each of which was offered fresh or after being buried. Carabid beetles readily accepted previously buried seeds as food. In total, Pseudoophonus rufipes and Amara littorea ate more fresh seeds than previously buried seeds, while the opposite was true for Harpalus affinis. The seeds of some species were even more attractive to carabids after burial than in the fresh state. For all the species of carabids tested, the diet breadth was similar when the beetles were fed fresh or buried seeds, but the preferences for fresh and buried seed of particular species were correlated only in P. rufipes and A. littorea. We measured the seed characteristics (mass and viability) likely to be associated with the loss of attractiveness to carabids during burial. The change in carabid consumption was not related to changes in any of these characteristics. This finding indicates that factors responsible for variation in seed acceptability are complex. This study provides the first conclusive evidence that invertebrate seed predators will feed on seeds from seed banks, although they prefer fresh seeds. [ABSTRACT FROM AUTHOR]

To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profiles) were compared in terms of their size (area under the seasonal profile curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profiles varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profiles revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this flexibility is an important factor in its invasive success. [ABSTRACT FROM AUTHOR]

The mating behaviour of Pyrrhocoris apterus in the laboratory is well studied, but little is known about it under natural conditions. In natural populations in Central Europe, overwintered adults start copulating in March and continue until their death. Caged females, kept under natural conditions in the permanent presence of males, copulated repeatedly. Their mating activity increased sharply until early April, then very slowly until the end of June and then declined as the females die-off. Half of copulations were short (< 5 h) and only 9% were longer than 1 day. By contrast, in natural populations, mating activity (percentage of individuals involved in copula) reached its maximum in April and then decreased until early July, when the overwintered adults die. The decline in mating frequency (percentage of adults involved in copula) was associated with a decrease in the availability of receptive females towards the end of the mating period. For a female, repeated copulation is necessary because sperm is nearly depleted after insemination of 3-5 egg batches. [ABSTRACT FROM AUTHOR]

Seeds of many species of plants may survive for a long time in the soil and germinate when brought to the surface, but whether they are subsequently eaten by seed predators is unknown. We examined the preferences of three species of carabids (Coleoptera: Carabidae) for 25 species of seeds and determined the difference in palatability between freshly dispersed and those buried for six years. The stability of their preferences was tested using a collection of seeds of different species, each of which was offered fresh or after being buried. Carabid beetles readily accepted previously buried seeds as food. In total, Pseudoophonus rufipes and Amara littorea ate more fresh seeds than previously buried seeds, while the opposite was true for Harpalus affinis. The seeds of some species were even more attractive to carabids after burial than in the fresh state. For all the species of carabids tested, the diet breadth was similar when the beetles were fed fresh or buried seeds, but the preferences for fresh and buried seed of particular species were correlated only in P. rufipes and A. littorea. We measured the seed characteristics (mass and viability) likely to be associated with the loss of attractiveness to carabids during burial. The change in carabid consumption was not related to changes in any of these characteristics. This finding indicates that factors responsible for variation in seed acceptability are complex. This study provides the first conclusive evidence that invertebrate seed predators will feed on seeds from seed banks, although they prefer fresh seeds. [ABSTRACT FROM AUTHOR]

To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profiles) were compared in terms of their size (area under the seasonal profile curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profiles varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profiles revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this flexibility is an important factor in its invasive success. [ABSTRACT FROM AUTHOR]

The mating behaviour of Pyrrhocoris apterus in the laboratory is well studied, but little is known about it under natural conditions. In natural populations in Central Europe, overwintered adults start copulating in March and continue until their death. Caged females, kept under natural conditions in the permanent presence of males, copulated repeatedly. Their mating activity increased sharply until early April, then very slowly until the end of June and then declined as the females die-off. Half of copulations were short (< 5 h) and only 9% were longer than 1 day. By contrast, in natural populations, mating activity (percentage of individuals involved in copula) reached its maximum in April and then decreased until early July, when the overwintered adults die. The decline in mating frequency (percentage of adults involved in copula) was associated with a decrease in the availability of receptive females towards the end of the mating period. For a female, repeated copulation is necessary because sperm is nearly depleted after insemination of 3-5 egg batches. [ABSTRACT FROM AUTHOR]

Seeds of many species of plants may survive for a long time in the soil and germinate when brought to the surface, but whether they are subsequently eaten by seed predators is unknown. We examined the preferences of three species of carabids (Coleoptera: Carabidae) for 25 species of seeds and determined the difference in palatability between freshly dispersed and those buried for six years. The stability of their preferences was tested using a collection of seeds of different species, each of which was offered fresh or after being buried. Carabid beetles readily accepted previously buried seeds as food. In total, Pseudoophonus rufipes and Amara littorea ate more fresh seeds than previously buried seeds, while the opposite was true for Harpalus affinis. The seeds of some species were even more attractive to carabids after burial than in the fresh state. For all the species of carabids tested, the diet breadth was similar when the beetles were fed fresh or buried seeds, but the preferences for fresh and buried seed of particular species were correlated only in P. rufipes and A. littorea. We measured the seed characteristics (mass and viability) likely to be associated with the loss of attractiveness to carabids during burial. The change in carabid consumption was not related to changes in any of these characteristics. This finding indicates that factors responsible for variation in seed acceptability are complex. This study provides the first conclusive evidence that invertebrate seed predators will feed on seeds from seed banks, although they prefer fresh seeds. [ABSTRACT FROM AUTHOR]

To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profiles) were compared in terms of their size (area under the seasonal profile curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profiles varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profiles revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this flexibility is an important factor in its invasive success. [ABSTRACT FROM AUTHOR]

Seeds of many species of plants may survive for a long time in the soil and germinate when brought to the surface, but whether they are subsequently eaten by seed predators is unknown. We examined the preferences of three species of carabids (Coleoptera: Carabidae) for 25 species of seeds and determined the difference in palatability between freshly dispersed and those buried for six years. The stability of their preferences was tested using a collection of seeds of different species, each of which was offered fresh or after being buried. Carabid beetles readily accepted previously buried seeds as food. In total, Pseudoophonus rufipes and Amara littorea ate more fresh seeds than previously buried seeds, while the opposite was true for Harpalus affinis. The seeds of some species were even more attractive to carabids after burial than in the fresh state. For all the species of carabids tested, the diet breadth was similar when the beetles were fed fresh or buried seeds, but the preferences for fresh and buried seed of particular species were correlated only in P. rufipes and A. littorea. We measured the seed characteristics (mass and viability) likely to be associated with the loss of attractiveness to carabids during burial. The change in carabid consumption was not related to changes in any of these characteristics. This fi nding indicates that factors responsible for variation in seed acceptability are complex. This study provides the fi rst conclusive evidence that invertebrate seed predators will feed on seeds from seed banks, although they prefer fresh seeds. [ABSTRACT FROM AUTHOR]

To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profiles) were compared in terms of their size (area under the seasonal profile curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profiles varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profiles revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this fl exibility is an important factor in its invasive success. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Flowers of dicotyledonous plants host communities of arthropod species. We studied the community associated with dandelion (Taraxacum section Ruderalia), a complex of apomictic micro-species abundant in central Europe. Identification of microspecies in the field was impracticable. These plants produce an abundance of flowers that host arthropod communities that are not yet fully documented. We investigated species occurrence, its diurnal and seasonal variation and some of the factors that determine the abundance of the dominant species. Insect and spiders were collected from 2010 to 2012 at a locality in Prague. Whole capitula were harvested at weekly intervals and resident arthropods were identified. Diurnal variation in insect presence and the effect of pollen and microclimate on some of the species were also examined. The insect community (> 200 species) consisted mainly of species of Hymenoptera (86 spp.), Coleoptera (56 spp.), Diptera (46 spp.) and Heteroptera (23 spp.). The most abundant were Thysanoptera (2 spp.). Pollen eaters/collectors and nectar feeders dominated over predators and occasional visitors. From April to mid-August, the insect community was dominated by Coleoptera, and later by Diptera and Hymenoptera. Except for Meligethes spp. and species breeding in the capitula, the insects occupied flowers during the daytime when the flowers were open (10-12 h in spring and only 2-4 h in late summer). The presence of Meligethes spp. in particular flowers was associated with the presence of pollen; the occurrence of Byturus ochraceus with pollen and flower temperature. Although pollination is not necessary, dandelion plants produce both nectar and pollen. The community of arthropods that visit dandelion flowers is rich despite their being ephemeral. The composition of local faunas of flower visitors, presence of floral rewards and flower microclimate are important factors determining the composition of the flower community. [ABSTRACT FROM AUTHOR]

Taxonomical bias for the intensity of research in natural sciences is well documented but less data exists for crop protection, weed and phytopathology sciences. Here we test a hypothesis predicting a positive relationship between the number of pests recorded in various taxa ("pest-taxa") in the Czech Republic, their economic importance and numbers of persons engaged in research of crop protection, weed, and phytopathology. In contrast, we established an imbalance in the distribution of manpower and the number of pest species. The most counterintuitive result of this study was that the number of scientists was weakly inversely related to the average economic importance of particular taxa. [ABSTRACT FROM AUTHOR]

Aphid populations show periodic fluctuations and many causes are attributed to their dynamic. We investigated the regulation by temperature of the aphid populations composed of Metopolophium dirhodum, Sitobion avenae, and Rhopalosiphum padi on winter wheat using a 24 years long time series data. We computed the sum of daily temperatures above 5°C, the threshold temperature for aphid development, and the sum of daily temperatures within the [0(threshold for wheat development),5] °C interval. Applying Generalised Additive Model framework we tested influences of temperature history expressed via degree days before the start of the aphid immigration on the length of their occurrence. We aimed to estimate the magnitude and direction of this influence, and how far to the past before the start of the aphid season the temperature effect goes and then identify processes responsible for the effect. We fitted four models that differed in the way of correcting for abundance in the previous year and in specification of temperature effects. Abundance in the previous year did not affect the length of period of aphid population growth on wheat. The temperature effect on the period length increased up to 123 days before the start of the current season, i.e. when wheat completed vernalization. Increased sum of daily temperatures above 5°C and the sum of daily temperatures within the [0,5] °C interval both shortened the length of period of aphid population growth. Stronger effect of the latter suggests that wheat can escape from aphid attacks if during winter temperatures range from 0 to 5°C. The temperature influence was not homogeneous in time. The strongest effect of past temperature was about 50 to 80 and 90 to 110 days before the beginning of the current aphid season indicating important role of termination of aphid egg dormancy and egg hatching. [ABSTRACT FROM AUTHOR]

Effects of floral herbivory (grazing flowers) by slugs on production and quality of seeds of herbaceous plants have been rarely quantified. We studied consequences of grazing by an invasive slug Arion lusitanicus (Mabille) for inflorescences of dandelion (Taraxacum officinale Weber ex Wiggers). In May 2008, a grassy site in Prague-Ruzyne (Czech Republic) was densely populated by dandelion inflorescences. Of the 40% of the flowers grazed by the slug, 70% died before seed dispersal and seed was eaten from 10% of the closed mature inflorescences. Viability of seeds from inflorescences that survived slug grazing was not affected. In addition to seedling predation, grazing of flowers may be an important source of dandelion mortality at sites where this slug is abundant. [ABSTRACT FROM AUTHOR]

Seeds of weeds buried by tillage may germinate at depths from which seedlings cannot establish. In barnyardgrass (Echinochloa crus-galli) we investigated how fatal germination was influenced by the depth and time of seed burial. The proportion of germinated seeds decreased with burial depth to 0-20% at ≥ 0.1 m depth which is fatal for seedling establishment. The percentage of fatal germination was greater for the seeds buried during the spring season than during autumn. Germination was influenced by seed pre-treatment, after ripening or stratification. Spring ploughing of non-dormant seeds below 0.1 m depth induces fatal germination, decreasing in this way seed bank of barnyardgrass. [ABSTRACT FROM AUTHOR]

Aphidophagous and coccidophagous ladybirds, similar to their prey, show marked differences in their pace of life (Dixon, 2000), in particular in their rate of development, with all stages of aphidophagous species developing much faster than those of coccidophagous species. Two hypotheses are proposed to account for the large difference in the pace of life of these two groups. These are that differences in the rate of development are a result of differences in lower temperature thresholds for development or the quality of their respective prey as food (Dixon et al., 2011). Analysis of published results on the rates of development of the eggs of ladybirds indicates that the inverse relationships between the number of day-degrees required for development ( K) and the lower temperature threshold for development ( tdmin) of these two groups are significantly different. In particular, the respective tdmin overlap and K of the aphidophagous and coccidophagous species with a similar tdmin are, on average, 38 and 117 day-degrees (Do). The relationship between the rate of development ( R) and temperature ( T) for aphids reared on poor- or high-quality foods indicates that, although the value of tdmin of a species depends on food quality, K does not, showing that it is unlikely that K is governed by food quality. Thus, there is little support for differences in either the tdmin or food quality governing the difference in the pace of life of these two groups of ladybirds. The results indicate that the physiological mechanism that may govern the difference in the pace of life between these two groups is the number of day-degrees ( K) needed to complete their development. The possible evolutionary reason for this is discussed. [ABSTRACT FROM AUTHOR]

Many rove beetle (Coleoptera: Staphylinidae) species are carnivorous. Despite their positive role in the biological control of agricultural arthropod pests rove beetles are relatively poorly studied in general, and little is known about their habitat associations including their occurrence and seasonal activity in the apple-orchard environment. In 1994, abundance and composition of adult staphylinid taxocenosis was established in a 12-years-old apple orchard at Prague-Ruzyně, and compared with taxocenoses inhabiting nearby grassy ridge, winter wheat field and forest. The staphylinids were collected throughout the vegetation season using unbaited pitfall traps. Staphylinid activity was highest in the apple orchard where 28 species were established in the total sample of 1238 individuals. Dominant species Drusilla canaliculata (F.), Ocypus nero semilanatus Müller, Dinarea angustula (Gyllenhal) and Oxytelus insecatus Gravenhorst together represented 93% of the total sample. The former two species dominated also the taxocenosis of grassy ridge and could disperse to the orchard from surrounding swards. Most established species are polyphagous predators or parasitoids that might contribute to the biological control of some orchard pests. [ABSTRACT FROM AUTHOR]

Abstract: This review surveys the literature dealing with food relationships of coccidophagous, aleurodophagous and psyllophagous coccinellids. While in the cold temperate climate aphids are the dominant prey group (68% of ladybird species), globally, coccids are the dominant prey group of 36% of coccinellid species, and only 20% prey primarily on aphids. Special attention is given to the physiological and environmental factors that affect the nutritive suitability of prey. In particular, the physiological states and development stages of the predators and prey species, sensory cues used in foraging, interspecific differences in the suitability of prey, the effects of host plants on predator–prey interactions, and climatic and seasonal effects on predation are discussed. Considerably more research has been conducted on the utility of coccinellids as predators of coccids than on aleyrodids and psyllids, in part because of the characteristics of whiteflies that restrict their consumption by polyphagous species. A major conclusion is that the assumption that coccinellids (and other predators) are of limited value in managing these non-aphid sternorrhynchans is premature, and that more research is sorely needed on these prey groups from predator ecologists. [Copyright &y& Elsevier]

1. The objective of this study was to test the theoretical prediction that the thermal tolerance range for development in insects should be about 20 °C. 2. The data on the thermal requirements for development of 66 species from eight orders of insects was obtained from the literature. The temperatures at which the developmental rates are at their minimum and maximum was obtained for each population by defining the relationship between developmental rate (1/ D) and temperature, using either Lactin et al.'s (1995 ) or Briére et al.'s (1999 ) model. 3. Thermal windows, i.e. the range in temperature between the minimum and maximum rate of development for individual species, and the relationship between the minimum and maximum temperatures, were examined. 4. The mean thermal window, 19·8 °C with 95% confidence interval 19·1–20·5 and range 13·3−28·6, was influenced by species phylogeny, with the windows narrower for species having a true pupal stage, but not by ecological traits thought to affect species thermal requirements. The relationship between the minimum and maximum temperatures was highly significant and independent of species phylogeny. 5. Theory and this analysis of empirical data indicate that each species of insect can only develop over a limited range of temperatures independent of species traits. In addition, the relationship between the minimum and maximum developmental rates co-vary independent of species phylogeny. This may help identify the precise nature of the physiological mechanism underlying the seasonal development and distribution of insects, and possibly other ectotherms. [ABSTRACT FROM AUTHOR]

Abstract: Rumex obtusifolius is the preferred host plant of Coreus marginatus. The survival of nymphal C. marginatus, its development on a diet of R. obtusifolius and the effects of herbivory on Rumex seed were investigated. Although the diet consisting solely of seed did not allow complete development, growth rates and survival of nymphs were proportionate to the quantity of provided seed. Nymphal feeding did not noticeably decrease seed mass but significantly decreased the proportion of germinating seed. In this way C. marginatus affects Rumex reproduction. Germination ability decreased with decreasing seed availability and increasing duration of seed predation. Nymphs confined to Rumex inflorescences in the field-completed development and significantly reduced both seed mass and germination ability. The mortality of seed overwintering on standing dry shoots of dock plants was moderately affected by feeding of C. marginatus. [Copyright &y& Elsevier]

Abstract. 1. The population growth of three aphid species, Metopolophium dirhodum (Walker), Rhopalosiphum padi (L.), and Sitobion avenae (F.), on winter wheat, was analysed by regression. The calculations were based on censuses of aphids made in 268 plots at 3- or 7-day intervals for 10 years on leaves and 6 years on ears. The calculations were made separately for each plot each year, then repeated on the pooled data from all plots monitored in a year. 2. At the level of individual plots, no population growth was detected at very low densities. At high densities, the populations grew exponentially and the growth rates did not decrease with increasing aphid density. 3. Significant growth was always detected in the pooled data. These growth rates decreased significantly at the highest densities. Field estimates of the intrinsic rate of increase derived from these data ranged from 0.010 to 0.026 for M. dirhodum , 0.0071–0.011 for R. padi , and 0.00078–0.0061 and 0.0015–0.13 for S. avenae , on leaves and ears respectively . 4. The apparent lack of growth in the individual plots at low densities is attributable to small sample size. It is concluded that the natural enemy ravine in the population dynamics of cereal aphids, identified by Southwood and Comins (1976), is a consequence of low population densities at which population increase is undetectable unless very large samples are taken. [ABSTRACT FROM AUTHOR]

Blue spruce (Picea pungens) has been planted in urban greenery as an ornamental tree in central Europe for more than 150 years. We investigated whether this nonnative spruce is a convenient habitat for ladybirds (Coleoptera, Coccinellidae). In 2021 and 2022, adults and larvae were sampled in four towns in Slovakia at monthly intervals throughout the growing season, from April to October. We recorded adults of 27 species and larvae of 11 ladybird species. Conifer specialist ladybird species predominated both in adult and larval communities (adults – 9 species, 85.2% of all individuals; larvae – 7 species, 92.1% of all individuals). Exochomus quadripustulatus and Aphidecta obliterata were the most common in adult (31.8% and 33.5% of all individuals, respectively) and larval (57.5% and 25.1% of all individuals, respectively) communities. The most abundant generalist species was nonnative invasive Harmonia axyridis (adults – 5.6%, larvae – 6.8% of all individuals). Adults and larvae of ladybirds were more abundant on solitary trees than on trees growing in groups. Our results confirmed that blue spruce hosts rich ladybird communities and provides them shelter and food resources. [ABSTRACT FROM AUTHOR]

Ladybirds (Coleoptera: Coccinellidae) provide services that are critical to food production, and they fulfill an ecological role as a food source for predators. The richness, abundance, and distribution of ladybirds, however, are compromised by many anthropogenic threats. Meanwhile, a lack of knowledge of the conservation status of most species and the factors driving their population dynamics hinders the development and implementation of conservation strategies for ladybirds. We conducted a review of the literature on the ecology, diversity, and conservation of ladybirds to identify their key ecological threats. Ladybird populations are most affected by climate factors, landscape composition, and biological invasions. We suggest mitigating actions for ladybird conservation and recovery. Short‐term actions include citizen science programs and education, protective measures for habitat recovery and threatened species, prevention of the introduction of non‐native species, and the maintenance and restoration of natural areas and landscape heterogeneity. Mid‐term actions involve the analysis of data from monitoring programs and insect collections to disentangle the effect of different threats to ladybird populations, understand habitat use by taxa on which there is limited knowledge, and quantify temporal trends of abundance, diversity, and biomass along a management‐intensity gradient. Long‐term actions include the development of a worldwide monitoring program based on standardized sampling to fill data gaps, increase explanatory power, streamline analyses, and facilitate global collaborations. Article impact statement: In light of major ecological threats, mitigating actions at different timescales are crucial for ladybird conservation and recovery. [ABSTRACT FROM AUTHOR]

We tested whether two basic thermal requirements for insect development, lower developmental thresholds, i.e. temperatures at which development ceases, and sums of effective temperatures, i.e. numbers of day degrees above the lower developmental thresholds necessary to complete development, differ among insect species that proved to be successful invaders in regions outside their native range and those that did not. Focusing on species traits underlying invasiveness that are related to temperature provides insights into the mechanisms of insect invasions. The screening of thermal requirements thus could improve risk-assessment schemes by incorporating these traits in predictions of potentially invasive insect species. We compared 100 pairs of taxonomically-related species originating from the same continent, one invasive and the other not reported as invasive. Invasive species have higher lower developmental thresholds than those never recorded outside their native ranges. Invasive species also have a lower sum of effective temperatures, though not significantly. However, the differences between invasive and non-invasive species in the two physiological measures were significantly inversely correlated. This result suggests that many species are currently prevented from invading by low temperatures in some parts of the world. Those species that will overcome current climatic constraints in regions outside their native distribution due to climate change could become even more serious future invaders than present-day species, due to their potentially faster development. [ABSTRACT FROM AUTHOR]

The harlequin ladybird beetle Harmonia axyridis (Coleoptera, Coccinellidae) has invaded and established in Slovakia. Following unintentional introduction in 2008, the spread of the alien coccinellid was very fast. By the end of 2009, it was recorded across the whole country, and by the end of 2012 it was widely distributed and common in various habitats, particularly gardens, orchards and urban areas, where it was most frequent on trees. The rate of eastward spread was approximately 200 km year-1, similar to the overall rate of spread in Europe. Between 2008 and 2012, the coccinellid was recorded in a total of 153 localities, in altitudes ranging from 98 to 1,250 m. Most records of this species were made in lowlands, hilly areas and valleys separating mountain ridges. However, it was only rarely documented in areas above 700 m a.s.l. The non-melanic colour form (f. succinea) was dominant along a longitudinal transect including eight urban areas across Slovakia, with the frequency of melanic forms (f. spectabilis and f. conspicua together) between 6.3 and 19.2% and a median equal to 10.5%. The invasion history and distribution of H. axyridis in Slovakia are discussed with regard to the time sequence of records, rate of spread, altitudinal distribution, anthropogenic dispersal, effective recording, proportion of melanic forms and other relevant aspects associated with the spread of this successful invader. [ABSTRACT FROM AUTHOR]

Chemical and agronomical control of volunteer plants is difficult, especially in reduced-input cropping systems where feeding by natural herbivores may become an important cause of their mortality. The consumption of the early growth stages of winter oilseed rape (Brassica napus L. ssp. napus) by five species of ground-surface invertebrates abundant in rape fields of Central Europe was studied under laboratory conditions. The species were particular in their preferences for growth stages of oilseed rape. The gastropods Arion lusitanicus and Helix pomatia preferred seedlings rather than seeds, whereas all three species of arthropods rejected seedlings. Pseudoophonus rufipes consumed all seed stages with similar intensity, while Pterostichus melanarius readily accepted fresh, dry and imbibed seeds. The overall consumption by the isopod Armadillidium vulgare was low and concentrated on exhumed seeds. Seeds and the early growth stages of oilseed rape are thus susceptible to invertebrate predation, each stage being killed by a specific group of invertebrate predators. [ABSTRACT FROM AUTHOR]

Understanding of habitat favourability has wide relevance to the invasion biology of alien species. We studied the seasonal dynamics of the alien ladybird Harmonia axyridis (Coleoptera: Coccinellidae) in monoculture Scots pine forest stands in south-west Slovakia, Central Europe, from April 2013 to March 2015. Adult H. axyridis were collected monthly across seven randomly selected pine stands of different ages and canopy closure, from the lower branches of pine trees, and larvae were recorded qualitatively. Adults were recorded all year round, most abundantly in November and least abundantly in February. The relationship between the abundance of H. axyridis and selected forest stand characteristics was modelled using the negative binomial Generalized Additive Model with penalized spline component in month (seasonality) effect, year, canopy closure and age effects and the random effect of forest stand (sample area effect). The abundance of H. axyridis was significantly influenced by the age of stand and seasonality (with month granularity) for both closed and open canopy stands, whereas the effects of canopy closure and sample area were not significant. The bimodal pattern of seasonal dynamics of H. axyridis on Scots pine was common for closed and open canopy stands, with two peaks reflecting the cyclic movement of the species from and to overwintering sites. Harmonia axyridis utilized certain pine stands preferably for foraging during the growing season and certain stands for refuge during winter. The ladybirds were found in highest numbers in the 15 year old closed canopy stand (overwintering site). The occurrence of both adults and larvae in most stands indicated a suitability of Scots pine forest for ladybird breeding. The model of year-round dynamics of H. axyridis has been presented for the first time within the invaded range of the ladybird in Europe. [ABSTRACT FROM AUTHOR]

Many species of ground beetles (Coleoptera: Carabidae) are important predators of seeds. While the consumption of herb seeds has been intensively studied, little attention has been paid to the consumption of seeds of gymnosperm plants. Here, we determined the consumption of seeds of six coniferous species by four common carabid species and compared carabid preference for conifer and selected common angiosperm weed seed species. In no-choice experiments, the large carabid species Pseudoophonus rufipes preferentially consumed the seeds of Picea abies, Larix decidua and Pinus sylvestris. Pinus sylvestris was also preferred by another large carabid, Pterostichus melanarius. The smaller carabids Harpalus affinis and H. rubripes consumed conifer seeds reluctantly. The intensity of seed consumption by carabids decreased with increasing seed size. In choice experiments, both of the large carabid species preferred the small conifer seeds of P. sylvestris and L. decidua over herb seeds of similar size (Dipsacus fullonum, Galeopsis speciosa, Polygonum lapathifolium). Carabids may prefer conifer seeds because of their soft seed coats, regardless of their chemical protections. Postdispersal predation of seeds by carabids may be an important mortality factor in some conifer species. [ABSTRACT FROM AUTHOR]

We surveyed ladybirds (Coleoptera: Coccinellidae) in 10 stands of Scots pine (Pinus sylvestris), all monoculture stands 5-100 years old, in western Slovakia, Central Europe, over two successive periods, October 2013 - March 2014 and October 2014 - March 2015. The winter in each period was exceptionally mild. Ladybirds were collected from the lower branches of pine trees using beating trays and were present in 61% of the 1040 samples (one sample containing ladybirds from 20 branches, 1 m long each). In total 3965 individuals of 20 species were recorded. Non-conifer dwelling species associated with broadleaved trees or herbaceous plants prevailed (45% of species), followed by conifer specialists (40%) and generalists (15%). Although 13 species were found at least in one winter month, December, January or February, only four of them, Exochomus quadripustulatus, Coccinella septempunctata, Harmonia axyridis and Hippodamia variegata, were recorded continually during both winters. The number of species, the abundance of all ladybirds and the abundance of dominant species (E. quadripustulatus, C. septempunctata and H. axyridis) decreased from late autumn towards winter and remained lowest during this most adverse time of the year for ladybirds. Overwintering species assemblages of ladybirds changed over time and varied with age of pine stand. Our results suggest that Scots pine in Central Europe supports species rich assemblages of ladybirds from late autumn to early spring and, being widely distributed, it could be suited to winter surveying of ladybirds at large spatial scales to reveal behavioural and ecological responses of species to changing weather or different climates. [ABSTRACT FROM AUTHOR]

Maximum aphid numbers on wheat are positively related to the length of the period elapsed from immigration to the population peak. We predicted that maximum abundances on late maturing cultivars would be greater than on early ones. This was tested using 8 spring wheat cultivars that differed in the length of time to senescence. In a 4-year experiment, numbers of aphids were checked at weekly intervals. Maximum abundances on late-maturing cultivars were significantly greater than those on early cultivars. However, the length of the vegetation period affected maximum abundances less than did the annual variation in aphid abundance. Genetic disposition for early ripening thus tends to decrease aphid numbers, but manipulation of this character is unlikely to become an important source of aphid resistance. [ABSTRACT FROM AUTHOR]

Seeds in soil banks can survive for many years before conditions become more suitable for germination. Meanwhile, seeds undergo changes in morphology and viability. In this study, we launched an artificial seed bank experiment that included 26 species of seeds. We excavated cohorts for 6–8 consecutive years after burial (YAB) in order to determine changes in the morphology (mass, volume, density, seed form) and proportion of fresh (thus persistent) seeds using a crush test as a measure of persistence. The change in seed morphology was fitted by linear and logistic regression, and the proportion of persistent seeds was fitted by logistic regression (effectively by the binomial GLM), which enabled estimation of 50 and 5% persistence times (PT50 and PT05). We found that in most species, seed mass, volume and proportion of persistent seeds declined with YAB, while other morphological traits were less variable, and the decline in these traits with YAB was best fitted with logistic regression. The decline in the proportion of persistent seeds was better fitted by the change in mass than by YAB in some species. Among the species included in this study, PT50 ranged from 1.2 to 10.5 years, and PT05 ranged from 2.1 to 24.3 years. These results can contribute to better understanding of the ecology of weed seed bank persistence in soil. Describing the morphological changes that the seeds undergo in the soil bank may improve our understanding of the biology of seed persistence and facilitate the identification of seeds from the soil bank. [ABSTRACT FROM AUTHOR]