 |
SEPG 2032 - Date Awarded 2002
Increasing distance between extinction-prone local host populations reduces regional persistence of parasitoids in a field experiment
Gisep Rauch & Wolfgang W. Weisser
Abstract
Dispersal rate is a key factor for host-parasitoid metapopulations to persist regionally, even when local populations go extinct frequently. In a field experiment we tested the influence of dispersal rate on regional persistence time of the locally unstable parasitoid Lysiphlebus hirticornis. Regional persistence was measured as time surviving in a host population group. A host population group consisted of local populations of the aphid Metopeurum fuscoviride living on seven plants placed in a row. The parasitoid was released on the central plant. Parasitoid dispersal rate was manipulated by changing the distance between plants. Four distance treatments were established where the distance between the plants of one group were either one, four, 16 or 64 metres, respectively. Dispersal rate and regional persistence time of the parasitoid decreased with increasing distance. The regional persistence time was decreased to 50 % in the four metres distance treatment, to 4 % and 14 % in the 16 and 64 metres treatment compared to the one metre treatment. To our knowledge, this is the first demonstration of distance dependent regional persistence of a parasitoid in a field experiment.
Full report: SEPG2032
|
Home
