نتایج جستجو برای: parasitoid density
تعداد نتایج: 414309 فیلتر نتایج به سال:
Interactions of the parasitoids Palmistichus elaeisis Delvare & LaSalle and Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) with its alternative host Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) affect the success or failure of the mass production of these parasitoids for use in integrated pest management programs. The aim of this study was to evaluate changes ...
One frequent explanation for the failure of biological invasions is the Allee effect: due to positive density dependence, initially small invading populations may fail to establish and spread. Populations released for biological control are similar to fortuitous invading populations and may therefore suffer from Allee effects. However, unlike fortuitous invasions, biological control allows the ...
the mill moth, ephestia kuehniella zeller and indian meal moth, plodia interpunctella (hubner) are two injuriously important pests of stored products worldwide. harobracon hebetor (say) has been used as a biological control agent of moth’s larva in peanut storehouses and as well in packaged cereal products. in the present study, the efficacy of h. hebetor in parasitizing larva of the mill moth ...
Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity...
1. In the AÊ land islands of SW Finland, the parasitoid Cotesia melitaearum (Wilkonson) is a specialist on the Glanville fritillary butter ̄y, Melitaea cinxia (L.), which uses two host plants, Plantago lanceolata (L.) and Veronica spicata (L.). 2. Extensive survey data on the butter ̄y and parasitoid populations collected in 1994±97 were used to examine possible associations of parasitoid coloniz...
In order to succeed in biological control programs, not only is it crucial to understand the number of natural enemies to be released but also on how many sites per area this releasing must be performed. These variables might differ deeply among egg parasitoid species and crops worked. Therefore, these trials were carried out to evaluate the parasitism (%) in eggs of Anticarsia gemmatalis and P...
Body size is a major factor constraining the trophic structure and functioning of ecological communities. Food webs are known to respond to changes in basal resource abundance, and climate change can initiate compounding bottom-up effects on food-web structure through altered resource availability and quality. However, the effects of climate and co-occurring global changes, such as nitrogen dep...
introduction: lysiphlebus fabarum marshall (hymenoptera: braconidae: aphidiinae) is a common aphidiine parasitoid in central europe, where it attacks more than 70 species of aphids. although both unisexual (thelytokous) and bisexual (arrhenotokous) strains of l. fabarum have been reported in iran, the former appear to be more widely distributed. aphid control in iran relies heavily on pesticide...
An experiment was conducted to test whether parasitoid resistance within a single clonal line of pea aphid (Acyrthosiphon pisum) might increase after exposure to the parasitoid wasp Aphidius ervi. Any change in resistance was expected to occur through an increase in the density of protective symbiotic bacteria rather than genetic change within the aphid or the bacterial symbiont. Six aphid line...
The complex relationships of a crop with the pest, its natural enemies, and the climate factors exist in all the ecosystems, but the mathematic models has studied only some components to know the relation cause-effect. The most studied system has been concerned with the relationship pestnatural enemies such as prey-predator or host-parasitoid. The present paper shows a dynamical system for stud...
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