1. Ecosystem retrogression, the decline-phase of ecosystem development, occurs during the long-term absence of catastrophic disturbance. It usually involves increased nutrient limitation over time, and leads to reductions in primary productivity, decomposition, and nutrient cycling. 2. As a consequence, retrogression can alter the quality and abundance of host plants as food resources, but litt...

Mistletoes are aerial hemiparasitic plants which occupy patches of favorable habitat (host trees) surrounded by unfavorable habitat and may be possibly modeled as a metapopulation. A metapopulation is defined as a subdivided population that persists due to the balance between colonization and extinction in discrete habitat patches. Our aim was to evaluate the dynamics of the mistletoe Psittacan...

Ailanthus altissima is an invasive alien species in Europe. Biological control of this tree by Verticillium nonalfalfae a potential alternative approach. This study investigates host specificity, pathogenicity and transmission V. to neighbouring plants with root contact mini-ecosystems. led dieback all inoculated trees. Furthermore, was transmitted trees, causing wilt dieback, and, one case, Qu...

Rhagoletis juglandis Cresson is a specialist that deposits its eggs into the husks of developing walnut fruit. Like other walnut infesting ßies in the R. suavis group, R. juglandis actively superparasitizes its larval hosts. However, little is known regarding the degree to which hosts are reused and the ecological context under which host reuse occurs. This Þeld study examined the pattern of ho...

the relationship between female oviposition preference and offspring performance is a key area of study on the evolution of host specificity. this study investigates host prefer-ence of the polyphagous hover fly syrphus ribesii (diptera: syrphidae) and compares it with some components of its offspring`s performance. females and offspring were tested on six naturally used aphid hosts (blackberry...

The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning.We tested the effects of tree diversity and the proporti...