| 1. |
- Bommarco, Riccardo, et al.
(författare)
-
Outbreak suppression by predators depends on spatial distribution of prey
- 2007
-
Ingår i: Ecological Modelling. - : Elsevier BV. - 0304-3800 .- 1872-7026. ; 201:2, s. 163-170
-
Tidskriftsartikel (refereegranskat)abstract
- The capacity of a predator population to suppress a prey population that varies in abundance and spatial distribution is explored in a lattice simulation model. The model is based on empirically derived parameters for particular species. Within season predation by Pterostichus cupreus (Coleoptera: Carabidae) of varying densities and distributions of the prey Rhopalosiphum padi (Homoptera: Aphididae) in spring cereals was simulated. From these spatially explicit simulations prey population suppression was found to be largely dependent on the spatial distribution of the prey. A possible mechanism was that high degrees of prey aggregation provided refuge for the prey that, when aggregated, escaped detection by P. cupreus. In contrast, P. cupreus was found to efficiently suppress incipient outbreaks for evenly distributed prey populations, even at high prey densities. A higher predator density compensated for the lowered control ability of the predators for highly aggregated prey populations and hastened the decline of the prey population.
|
|
| 2. |
- Lundhagen, Anna, et al.
(författare)
-
Species-specific primers for predation studies of the pollen beetle, Meligethes aeneus (Coleoptera, Nitidulidae)
- 2009
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 9, s. 1132-1134
-
Tidskriftsartikel (refereegranskat)abstract
- Species-specific primers were developed for the pollen beetle (a pest in oilseed rape) for studies of predation by natural insect predators. Two forward and three reverse primers were designed within the mitochondrial COI gene and used in combination to amplify fragments in the size range of 163-290 bp. Remains of pollen beetle DNA were consistently detected in Pardosa spiders up to 24 h after ingestion but dropped drastically at 48 h. These primers will facilitate studies on biological control of this oilseed rape pest. Detection time was not correlated with fragment length as might be expected as the DNA gradually degrades into progressively shorter fragments over time.
|
|
| 3. |
- Åhman, Inger, et al.
(författare)
-
Impact of herbivory and pollination on performance and competitive ability of oilseed rape transformed for pollen beetle resistance
- 2009
-
Ingår i: Arthropod-Plant Interactions. - : Springer Science and Business Media LLC. - 1872-8855 .- 1872-8847. ; 3, s. 105-113
-
Tidskriftsartikel (refereegranskat)abstract
- Competitive ability of transgenic oilseed rape transformed with a pea lectin gene was estimated by comparisons of its performance when grown in a mixture with its non-transgenic counterpart and when grown singly, with and without pollen beetles present. The experiments were carried out in cages, once with bumblebees as pollinators and once without. In the absence of herbivory but with the presence of bumblebees, singly grown plant lines without lectin generally performed better than lines with lectin. Pollen beetles affected plant growth and reproduction, but there were no consistent differences between the lectin and non-lectin plant lines indicating that the transgenic trait did not protect plants from pest attack. Herbivory reduced the number of seeds when bumblebees were present. In the absence of bumblebees, however, plants produced more seeds with pollen beetles than without, indicating that some pollination was carried out by the beetles. Efficient pollination affected the competitive abilities of the lines; lectin lines were more competitive with bumblebees present and the reverse was true when bumblebees were absent. In the presence of bumblebees, lectin lines gained from being grown mixed with its non-transgenic counterpart. Because the transgenic plants expressed pea lectin in developing pollen it is possible that pollen quality in those plants was reduced, which may explain why the lectin lines had an advantage over non-lectin lines when exchange of pollen between the two plant types was facilitated by bumblebees.
|
|
