abstract myzus persicae sulzer is one of the serious pests in potato fields which has the ability of transmitting several viruses to the potato crop. throughout summer of 2008, field studies were carried out in ardabil to evaluate the seasonal population fluctuation of this aphid on 10 potato cultivars: granola, satina, moren, aozonia, cosima, agria, cosmos, kondor, diamant and savalan. density...

Zoophytophagous predators can substitute zoophagy for phytophagy to complete their development and reproduction. In such predators, variation in feeding behaviour is observed both across and within populations. This may be caused by genetic variation in diet specialization, some genotypes specializing on plant resources, whereas others rely mostly on prey to meet their energy and nutriment requ...

In ecology, prey switching refers to a predator’s adaptive change of habitat or diet in response to prey abundance. In this paper, we study piecewise-smooth models of predator-prey interactions with a linear trade-off in a predator’s prey preference. We consider optimally foraging predators and derive a model for a 1 predator-2 prey interaction with a tilted switching manifold between the two s...

There is an increasing realization of the diverse mechanisms by which parasites and pathogens influence the dynamics of host populations and communities. In multi-host systems, parasites may mediate food web dynamics with unexpected outcomes for host populations. Models have been used to explore the potential consequences of interactions between hosts, parasites and predators, but connections b...

Geocoris punctipes (Say) and Orius insidiosus (Say) are generalist predators found in awide range of crops, including cotton (GossypiumhirsutumL.) andmaize (ZeamaysL.), where they provide important biological control services by feeding on an array of pests, including eggs and small larvae of caterpillars. A high percentage of cotton and maize in the United States and several other countries ar...

1. Understanding predator–prey interactions of the arthropod community in any given ecosystem is essential in pinpointing the biological control services provided by natural enemies. 2. Hence, four prey-specific polymerase chain reaction (PCR) assays were developed to analyse the gut contents of the cotton predator community. The four targeted prey included a herbivore/pest, omnivore/pest, omni...

The distribution of weak and strong non-linear feeding interactions (i.e., functional responses) across the links of complex food webs is critically important for their stability. While empirical advances have unravelled constraints on single-prey functional responses, their validity in the context of complex food webs where most predators have multiple prey remain uncertain. In this study, we ...

Tadpoles involved in predator-prey interactions were studied in tropical wet forest in Costa Rica under laboratory and field conditions. Larvae of the frog Leptodactylus pentadactylas and naiads of the odonate Pantala flavescens are important predators on larvae of several species of frogs. The predators discriminate the prey on the basis of size and species, but not type of habitat in which pr...

Climate change is altering environmental temperature, a factor that influences ectothermic organisms by controlling rates of physiological processes. Demographic effects of warming, however, are determined by the expression of these physiological effects through predator-prey and other species interactions. Using field observations and controlled experiments, we measured how increasing temperat...