Habitat selection by dispersers is the focus of much theoretical models, most of which are based on the assumption of negative density dependence. The archetype of these models is the ideal free distribution, characterized by an evolutionary stable state where more competitors aggregate in better habitats, so that the fitness benefit of resource abundance is equally offset by the cost of compet...

When there is conspicuous underexploitation of a limited resource, it is worth asking, what mechanisms allow presumably valuable resources to be left unused? Evolutionary biologists have generated a wide variety of hypotheses to explain this, ranging from interdemic group selection to selfishly prudent individual restraint. We consider a situation in which, despite high intraspecific competitio...

Brown spot caused by Bipolaris oryzae is an important rice disease in Southern coast of Caspian Sea, the major rice growing region in Iran. A total of 45 Trichoderma isolates were obtained from rice paddy fields in Golestan and Mazandaran provinces which belonged to Trichoderma harzianum, T. virens and T. atroviride species. Initially, they were screened against B. oryzae by antagonism tests in...

Fungi of the genus Fusarium infect cereal crops during the growing season and cause head blight and other diseases. Their toxic secondary metabolites (mycotoxins) contaminate grains. Several dozen toxic compounds produced by fungal pathogens have been identified to date. Type B trichothecenes-deoxynivalenol, its acetyl derivatives and nivalenol (produced mainly by F. graminearum and F. culmorum...

Climate change affects the abundance, distribution and activity of natural enemies that are important for suppressing herbivore crop pests. Moreover, higher mean temperatures and increased frequency of climatic extremes are expected to induce different responses across trophic levels, potentially disrupting predator-prey interactions. Using field observations, we examined the response of an aph...

This study investigated the interactions of the pupal fruit ßy parasitoid, Dirhinus giffardii Silvestri, with each of four eggor larval-pupal fruit ßy parasitoids: Fopius arisanus (Sonan), Diachasmimorpha longicaudata (Ashmead), Diachasmimorpha kraussii Fullaway, and Psyttalia concolor (Szépligeti) in Hawaii. F. arisanus attacks host eggs, whereas the other three attack host larvae; all four pa...

Sheath blight, causes by Rhizoctonia spp., threaten maize yield every year throughout the world. Trichoderma could degrade Rhizoctonia solani on maize mainly via competition and hyperparasitism, whereas validamycin A could efficiently inhibit the growth of R. solani via disturbing the energy system. By contrast, validamycin A is efficient but it takes effect in a short period, while Trichoderma...

The parasitoid assemblage associated with a lepidopteran leafminer, Coptotriche japoniella (Tischeriidae), on an evergreen tree, Eurya japonica (Theaceae), was studied in the center of Japan to explore parasitoid coexistence mechanisms. The leafminer supported 12 parasitoid species. Eight abundant or common species were classiÞed into Þve guilds according to their koinobiont/ idiobiont mode and...

Understanding how resource diversification affects ecological interactions, food web structure and ecosystem functioning is essential in both fundamental applied ecology. While plant strategies (either in-field or around-field) are often proposed agricultural landscapes as practices to improve the biological control of herbivores by natural enemies, results remain variable unsure. Here, we stud...