| 1. |
- Björkman, Maria, et al.
(författare)
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Effects of plant competition and herbivore density on the development of the turnip root fly (Delia floralis) in an intercropping system
- 2009
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Ingår i: Arthropod-plant interactions. - : Springer Science and Business Media LLC. - 1872-8855 .- 1872-8847. ; 3, s. 55-62
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Tidskriftsartikel (refereegranskat)abstract
- In this study, interactive effects of plant competition and herbivory on plant quality and herbivore development were examined in a greenhouse experiment where cabbage plants [Brassica oleracea L. var. capitata (Brassicaceae)] were intercropped with red clover [Trifolium pratense L. (Fabaceae)]. Cabbages were grown with two red clover densities and attack rates by the root feeding herbivore the turnip root fly, Delia floralis Fall. (Diptera: Anthomyiidae). Above ground and below ground cabbage biomass was reduced through intercropping and larval damage. Intercropping also resulted in lower nitrogen and higher carbon root levels compared with levels in the roots of monocultured cabbage. Furthermore, both root nitrogen and carbon levels increased with herbivory. Root neutral detergent fibre (NDF) and lignin content increased in response to both increased plant competition and higher egg densities. For lignin, an interaction effect was observed in the form of elevated levels in intercropped plants subjected to larval damage, while levels in roots of monocultured cabbage remained unchanged. The quality changes brought about by clover competition affected D. floralis development negatively, which resulted in reduced pupal weight. In addition, increased egg density also decreased larval growth. The effects on the development of D. floralis in relation to host plant quality are discussed.
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| 2. |
- Einarsson, Bo, 1939-, et al.
(författare)
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Standardized mixed language programming for Fortran and C
- 2009
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Ingår i: ACM SIGPLAN Fortran Forum. - New York : ACM. - 1061-7264. ; 28:3, s. 8-22
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Tidskriftsartikel (refereegranskat)abstract
- Programmers have long practiced the matter of mixed language procedure calls. This is particularly true for the programming languages C and Fortran. The use of the alternate language often results in efficient running time or the effective use of human or other resources. Prior to the Fortran 2003 standard there was silence about how the two languages interoperated. Before this release there existed a set of differing ad hoc methods for making the inter-language calls. These typically depended on the Fortran and C compilers. The newer Fortran standard provides an intrinsic module, iso_c_binding, that permits the languages to interoperate. There remain restrictions regarding interoperable data types. This paper illustrates several programs that contain core exercises likely to be encountered by programmers. The source code is available from the first author's web site. Included is an illustration of a "trap" based on use of the ad hoc methods: A call from a C to a Fortran 2003 routine that passes a character in C to a character variable in Fortran results in a run-time error.
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| 3. |
- Hambäck, Peter, et al.
(författare)
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Scale-dependent responses in cabbage herbivores affect attack rates in spatially heterogenous systems
- 2009
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Ingår i: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791 .- 1618-0089. ; 10, s. 228-236
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Tidskriftsartikel (refereegranskat)abstract
- Herbivorous insects face a dilemma when selecting suitable hosts in a complex environment, and their sensory capability may often reduce the female capacity for proper selection. As a consequence, eggs are often deposited on inferior hosts, affecting both insect and host plant fitness. We examined the attack rates of three cabbage herbivores in monocultures and biculture plots of different Brassica oleracea genotypes, with different spatial heterogeneity. The main goals of the study were to improve our understanding of the spatial scales involved in herbivore search processes and to examine the possibility of using spatial heterogeneity for manipulating pest attack rates in cabbage cropping systems. The results showed that the host selection behaviour of the small white butterfly (Pieris rapae) was strongly dependent on spatial heterogeneity. The difference in egg density between plant genotypes was larger when contrasting plants were growing in close proximity than in monoculture. This suggests that P. rapae is able to differentiate among genotypes from a small distance, while selection is compromised at larger spatial scales. The two other herbivores in the study (Mamestra brassicae and Delia radicum) did not respond to heterogeneity at any spatial scale, but showed a constant preference hierarchy. This suggests that host selection in these species occurs after direct plant contact. The difference in species’ responses to spatial heterogeneity has consequences both for selection gradients in natural communities and for the potential to reduce pest attack in polyculture systems.
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| 4. |
- Hopkins, Richard
(författare)
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Role of Glucosinolates in Insect-Plant Relationships and Multitrophic Interactions
- 2009
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Ingår i: Annual Review of Entomology. - : Annual Reviews. - 0066-4170 .- 1545-4487. ; 54, s. 57-83
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Forskningsöversikt (refereegranskat)abstract
- Glucosinolates present classical examples of plant compounds affecting insect-plant interactions. They are found mainly in the family Brassiciceae, which includes several important crops. More than 120 different glucosinolates are known. The enzyme myrosinase, which is stored in specialized plant cells, converts glucosinolates to the toxic isothiocyanates. Insect herbivores may reduce the toxicity of glucosinolates and their products by excretion, detoxification, or behavioral adaptations. Glucosinolates also affect higher trophic levels, via reduced host or prey quality or because specialist herbivores may sequester glucosinolates for their own defense. There is substantial quantitative and qualitative variation between plant genotypes, tissues, and ontogenetic stages, which poses specific challenges to insect herbivores. Even though glucosinolates are constitutive defenses, their levels are influenced by abiotic and biotic factors including insect damage. Plant breeders may use knowledge on glucosinolates to increase insect resistance in Brassica crops. State-of-the-art techniques, such as mutant analysis and metabolomics, are necessary to identify the exact role of glucosinolates.
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| 5. |
- Styer, Katie L, et al.
(författare)
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Yersinia pestis kills Caenorhabditis elegans by a biofilm-independent process that involves novel virulence factors.
- 2005
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Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 6:10, s. 992-997
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Tidskriftsartikel (refereegranskat)abstract
- It is known that Yersinia pestis kills Caenorhabditis elegans by a biofilm-dependent mechanism that is similar to the mechanism used by the pathogen to block food intake in the flea vector. Using Y. pestis KIM 5, which lacks the genes that are required for biofilm formation, we show that Y. pestis can kill C. elegans by a biofilm-independent mechanism that correlates with the accumulation of the pathogen in the intestine. We used this novel Y. pestis-C. elegans pathogenesis system to show that previously known and unknown virulence-related genes are required for full virulence in C. elegans. Six Y. pestis mutants with insertions in genes that are not related to virulence before were isolated using C. elegans. One of the six mutants carried an insertion in a novel virulence gene and showed significantly reduced virulence in a mouse model of Y. pestis pathogenesis. Our results indicate that the Y. pestis-C. elegans pathogenesis system that is described here can be used to identify and study previously uncharacterized Y. pestis gene products required for virulence in mammalian systems.
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