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2. Development of ovaries, allometry of reproductive traits and fecundity of Episyrphus balteatus (Diptera: Syrphidae)
- Creator:
- Branquart, Etienne and Hemptinne, Jean-Louis
- Type:
- article, model:article, and TEXT
- Subject:
- Syrphidae, Episyrphus balteatus, fecundity, egg production, ovaries, and allometry
- Language:
- English
- Description:
- Episyrphus balteatus only matures eggs after emergence. Ovaries develop in 4 stages. In the absence of oviposition sites, females refrain from ovipositing and their ovaries progressively fill the abdomen and then egg resorption occurs. The potential fecundity, which is expressed by the ovariole number, the reproductive biomass and the abdomen volume, scales isometrically with the size of females. Egg size is much less variable and does not rise proportionally to body size. In laboratory conditions, females of E. balteatus might lay between 2,000 and 4,500 eggs during their life-time at a rate of 1 to 2 eggs per ovariole per day. Both life-time fecundity and rate of egg production are directly related to the size of females. The potential and realized fecundities are likely to be limited by the availability of food resources during larval and adult life, respectively.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3. Do flower mixtures with high functional diversity enhance aphid predators in wildflower strips?
- Creator:
- Hatt, Séverin, Uyttenbroeck, Roel, Lopes, Thomas, Mouchon, Pierre, Chen, Julian, Piqueray, Julien, Monty, Arnaud, and Francis, Frédéric
- Format:
- print, počítač, and online zdroj
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, pestřenkovití, slunéčkovití, Syrphidae, Coccinellidae, Chrysopidae, agri-environmental measure, conservation biological control, wildflower strips, functional diversity, Rao's index, 2, and 59
- Language:
- English
- Description:
- Among the semi-natural elements in agricultural landscapes, wildflower strips sown at field margins or within fields are potential habitats for the natural enemies of insect pests. As insects are sensitive to a variety of flower traits, we hypothesized that mixtures with high functional diversity attract and support a higher abundance and species richness of aphid flower visiting predators than mixtures with low functional diversity. During a field experiment, repeated over two years (2014 and 2015) in Gembloux (Belgium), aphid predators (i.e., lacewings, ladybeetles and hoverflies) were pan-trapped in five sown flower mixtures (including a control mixture, with three replicates of each mixture) of low to high functional diversity based on seven traits (i.e., flower colour, ultra-violet reflectance and pattern, start and duration of flowering, height and flower class, primarily based on corolla morphology). In both years, the species of flowering plants in the sown mixtures (i.e., sown and spontaneous flowers) were listed, and the realized functional diversity in each plot calculated. Over the two years, a high functional diversity was not associated with high abundance and richness of aphid predators. Moreover, ladybeetles, which made up the majority of the predators trapped, were more abundant in mixtures with very low or intermediate functional diversity at sowing, especially in 2014. We hypothesize that certain flowers, which were abundant in certain mixtures (and not in those exhibiting the highest functional diversity), attracted predators and were sufficiently abundant to support them. Our results present novel information that could be used for developing flower mixtures that provide effective ecosystem services, such as pest control., Séverin Hatt, Roel Uyttenbroeck, Thomas Lopes, Pierre Mouchon, Julian Chen, Julien Piqueray, Arnaud Monty, Frédéric Francis., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Efficiency of two methods of sampling used to assess the abundance and species diversity of adult Syrphidae (Diptera) in mountainous meadows in the Austrian and Swiss Alps
- Creator:
- Hussain, Raja I, Walcher, Ronnie, Brandl, David, Arnberger, Arne, Zaller, Johann G, and Frank, Thomas
- Format:
- print, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- dvoukřídlí, pestřenkovití, Diptera, Syrphidae, hoverflies, sampling methods, observation-plot, line-transect, alpine grassland, 2, and 59
- Language:
- English
- Description:
- The outcome of assessments of the biodiversity of a taxonomic group often depend on the sampling method. The choice of an adequate method is especially important for biomonitoring purposes. In this study, the effectiveness of two methods of sampling syrphids (Diptera: Syrphidae) is compared: observation plot method vs. line transect, both sampled by sweep netting. Altogether, 18 meadows were selected in three mountain regions in the Austrian and Swiss Alps. We recorded a significantly higher abundance and richness of syrphids using the observation plot method than the line transect method in 2015. Comparing data for one region recorded in 2015 and 2016, similar results were obtained. Syrphid species assemblages were affected by sampling method in both years. More syrphid species and individuals were recorded using the observation plot method, which makes it more suitable for studies aiming at comparing differences in the numbers of adult syrphids in different grassland habitats., Raja I. Hussain, Ronnie Walcher, David Brandl, Arne Arnberger, Johann G. Zaller, Thomas Frank., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
5. Evolution of prey specialization in aphidophagous syrphids of the genera Melanostoma and Platycheirus (Diptera: Syrphidae) 1. Body size, development and prey traits
- Creator:
- Dziock, Frank
- Type:
- article, model:article, and TEXT
- Subject:
- Diptera, Syrphidae, Melanostoma, Platycheirus, aphidophaga, prey specialization, aphids, traits, body size, and life history
- Language:
- English
- Description:
- Interactions between syrphid predators and their prey are poorly known. The adaptations of syrphids to aphid defences and the consequences for the evolution of life history traits in these predators especially are mostly unstudied. This is the first of two papers investigating the evolution of prey specialization in aphidophagous hoverflies. The study focuses on two questions: (1) Are differences in the body size of syrphid predators reflected in differences in the size of their prey? (2) Are differences in body size, body mass and development time of the syrphid predators correlated with the defence strategies of their aphid prey (e.g. mobility, toxicity)? Platycheirus clypeatus (Meigen, 1822), Platycheirus fulviventris (Macquart, 1829), Melanostoma mellinum (Linnaeus, 1758), and Melanostoma scalare (Fabricius, 1794), which differ considerably in their prey specialization, but are closely related, were chosen as model species. Life history data for these syrphids came from a laboratory study, and that for the aphids from a literature survey. These syrphid species can be arranged on a gradient of increasing prey specialization, from 32 prey species for the generalist M. mellinum and only 3 for the specialist P. fulviventris. Differences in prey specialization were even more evident when the defence ability of the various species of aphid prey was considered. For instance, the specialization on ant-attended aphids in M. scalare. Larvae exhibited a one or two weeks diapause which made the determination of developmental time imprecise. Body size of the predators was not reflected in that of their aphid prey. The postulated relationship between body size of the predator and the defence strategies of their prey was not supported by our data. A comparison of a wider range of syrphid species from different taxonomic groupings together with a phylogenetic correction procedure might reveal clearer trends. The second part of this paper (Dziock, in prep.) will investigate the correlation between prey specialization and reproductive strategies (i.e. clutch size, egg size and number) and will put the results into a broader framework.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6. Genetic characterization of the Balkan endemic species, Merodon desuturinus (Diptera: Syrphidae)
- Creator:
- Milankov, Vesna, Gunilla, Stahls, and Vujić, Ante
- Type:
- article, model:article, and TEXT
- Subject:
- Allozymes, mtDNA, genetic characterization, genetic variability, Syrphidae, and Merodon desuturinus
- Language:
- English
- Description:
- Variation of 15 nuclear allozyme genes and a 708 bp fragment of DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene were surveyed in a population of a hoverfly species, Merodon desuturinus Vujić, Šimić & Radenković, 1995 (Diptera, Syrphidae), endemic to the Balkan Peninsula. Based on phylogeography and taxonomy, Merodon desuturinus is of special interest from a biogeographical and conservation perspective. Characterization and determination of genetic relationships between M. desuturinus and taxa of the M. aureus, M. avidus, and M. ruficornis groups on the Balkan Peninsula were estimated based on molecular markers (allozymes and COI sequences). We observed that the mean number of alleles per allozyme locus was 1.1, frequency of polymorphic loci 0.067, and heterozygotes were absent. Our results showed an extremely low genetic variability in the M. desuturinus population sampled. We suggest that this taxon calls for a conservation management plan, as it is likely a vulnerable and threatened taxon, an endemic, spatially divided species and represents a unique genetic unit on the Balkan Peninsula.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
7. Genetic structure and phenotypic diversity of two northern populations of Cheilosia aff. longula (Diptera: Syrphidae) has implications for evolution and conservation
- Creator:
- Milankov, Vesna, Francuski, Ljubinka, Ludoški, Jasmina, Stahls, Gunilla, and Vujić, Ante
- Type:
- article, model:article, and TEXT
- Subject:
- Diptera, Syrphidae, Cheilosia aff. longula, allozymes, asymmetry, COI mtDNA, genetic diversity, ITS2 rDNA, and wing geometric morphometrics
- Language:
- English
- Description:
- The genetic structure and phenotypic diversity of two populations of Cheilosia aff. longula (Diptera: Syrphidae) in Lapland, Finland, were examined using DNA sequencing, protein electrophoresis, and geometric morphometrics. The morphological identification of the species were verified using partial sequences of mitochondrial cytochrome c oxidase subunit I (COI mtDNA), and the nuclear ribosomal internal transcribed region 2 (ITS2 rDNA), and comparing the corresponding sequences of Cheilosia aff. longula and the closely related C. longula. Two and three haplotypes of the genes COI mtDNA and ITS2 rDNA were identified in the two populations. Analysis of 12 isozyme loci showed an extremely low genetic variability in the populations originating from Utsjoki and Kevo. Discriminant analysis combined with canonical variate analysis revealed inter-population divergence in wing shape. Variation among genetically diverse individuals, both within- and among studied populations was studied, and directional (DA) and fluctuating asymmetry (FA) estimated using landmarks in the framework of geometric morphometrics. It is likely that the documented DA and FA asymmetry in both wing shape and size reflects the developmental instability of the individuals studied. By using Procrustes ANOVA the locations of particular landmarks responsible for the variation in shape were determined. The decomposition of the components of variance accorded to each landmark showed that the landmarks differed in the percentage of variation they accounted for (DA, FA and variation among individuals). In the discussion the implications of the reduced genetic diversity and asymmetry in wing traits for conservation is considered.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
8. Immature stages, morphology and feeding behaviour of the saprophytic syrphids Copestylum tamaulipanum and Copestylum lentum (Diptera: Syrphidae)
- Creator:
- Marcos-García, Ma Angeles and Pérez-Baňón, Celeste
- Type:
- article, model:article, and TEXT
- Subject:
- Syrphidae, Copestylum tamaulipanum, Copestylum lentum, immature stages, morphology, feeding behaviour, and Cactaceae
- Language:
- English
- Description:
- Adults of Copestylum tamaulipanum and C. lentum were reared from larvae collected from decaying platyclades of the cactus Opuntia in the state of Veracruz (Mexico). The larvae and puparia of both species, as well as preliminary data about their life cycles are described. The feeding behaviour of the larva in relation to the morphology of the cephalopharyngeal skeleton is analysed.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
9. Influence of urbanisation and plants on the diversity and abundance of aphids and their ladybird and hoverfly predators in domestic gardens
- Creator:
- Rocha, Elise A, Souza, Estevão N.F, Bleakley, Lewis A.D, Burley, Christopher, Mott, Jade L, Rue-Glutting, Gloria, and Fellowes, Mark D.E
- Format:
- print, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- polokřídlí, mšicovití, dvoukřídlí, slunéčkovití, pestřenkovití, životní prostředí měst, Hemiptera, Aphididae, Coccinellidae, Diptera, Syrphidae, urban ecology, Coleoptera, species interactions, diversity, abundance, 2, and 59
- Language:
- English
- Description:
- Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Hemiptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) influence the local diversity and abundance of aphids, ladybirds, and hoverflies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfly species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfly abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may reflect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fine scale habitat variables that are determined by garden owners have the potential to greatly affect the diversity of aphids and their primary predators., Elise A. Rocha, Estevão N.F. Souza, Lewis A.D. Bleakley, Christopher Burley, Jade L. Mott, Gloria Rue-Glutting, Mark D.E. Fellowes., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
10. Intraguild interactions between the predatory hoverfly Episyrphus balteatus (Diptera: Syrphidae) and the Asian ladybird, Harmonia axyridis (Coleoptera: Coccinellidae): Effect of larval tracks
- Creator:
- Almohamad, Raki, Verheggen, Francois J., Francis, Frédéric, and Haubruge, Eric
- Type:
- article, model:article, and TEXT
- Subject:
- Syrphidae, Coccinellidae, Episyrphus balteatus, Harmonia axyridis, larval tracks, Vicia faba, aphids, and oviposition-deterring substances
- Language:
- English
- Description:
- The effects of the larval tracks of Episyrphus balteatus DeGeer (Diptera: Syrphidae) and Harmonia axyridis Pallas (Coleoptera: Coccinellidae) on the egg laying behavior of females of the predatory hoverfly E. balteatus were investigated in two-choice experiments. The oviposition response of H. axyridis to larval tracks of E. balteatus was also tested in one-choice experiments. Gravid E. balteatus females laid significantly fewer eggs on leaf discs with aphids and contaminated with tracks of conspecific or heterospecific larvae than on control leaf discs. H. axyridis females laid similar numbers of eggs in Petri dishes with aphids and contaminated with the tracks of E. balteatus larvae as in control Petri dishes. This indicates that E. balteatus females lay fewer eggs at sites where there are conspecific and heterospecific larval tracks, whereas the tracks of the syrphid larvae did not deter H. axyridis females from laying eggs.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
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