نتایج جستجو برای: larval density
تعداد نتایج: 433688 فیلتر نتایج به سال:
OBJECTIVE To determine the effects of environmental characteristics of larval habitats on distribution and abundance of anopheline mosquitoes in Bashagard county, a malarious area in southeast of Iran. METHODS Larvae were collected monthly using the standard dipping method and identified using a morphological-based key. Environmental characteristics of the larval habitats were recorded. Water...
the population response of heliothis armigera larvae to nuclear polyhedrosis virus (npv) was investigated. the virus was introduced by permitting the larvae to feed on lettuce leaves. median lethal doses (ld50) were determined. the estimated ld50 values for the first, second, third, early, and late fourth larval instars were 5, 141, 1226, 5168 and 24553 polyhedra per larva respectively. in ...
High Density Induces a Large Head in Larval <i>Hynobius retardatus</i> from a Low Density Population
Background The Mantispidae are a distinctive group of Neuroptera known for the adults' possession of raptorial forelegs. There are four recognised, extant subfamilies of Mantispidae: the Mantispinae, Symphrasinae, Calomantispinae and Drepanicinae. The life history and larval behaviour of the subfamily Mantispinae is best known: the immatures are spider egg predators. Among the three remaining s...
International efforts are underway to establish well-connected systems of marine protected areas (MPAs) covering at least 10% of the ocean by 2020. But the nature and dynamics of ocean ecosystem connectivity are poorly understood, with unresolved effects of climate variability. We used 40-year runs of a particle tracking model to examine the sensitivity of an MPA network for habitat-forming col...
abstract: the potato tuberworm, phthorimaea operculella (zeller), is an important insect pest of potato (solanum tuberosum l.) in the storage and field in most parts of the world especially in tropical and subtropical regions due to its close relationship with the host, high reproductive potential and high economic losses. information on host preference, life table parameters and digestive en...
Results of previous laboratory studies suggest that high population density often buffers the effects of chemical stressors that predominately increase mortality. Mortality stressors act to release more resources for the survivors and, therefore, produce less-than-additive effects. By contrast, growth stressors are expected to have opposite results or more-than-additive effects. We investigated...
Effective methods are needed to protect ash trees (Fraxinus spp.) from emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive buprestid that has killed millions of North American ash (Fraxinus spp.) trees. We randomly assigned 175 ash trees (11.5Ð48.1 cm in diameter) in 25 blocks located in three study sites in Michigan to one of seven insecticide treatments in ...
Scant attention has been paid to invasive species whose range and abundance has decreased after an initial range expansion. One such species is the browntail moth Euproctis chrysorrhoea L, which was discovered in the eastern United States in 1897. Its range expanded until 1914; after 1915, however, its range contracted and now it persists in only two isolated coastal locations. Although a biolo...
37 The standard view of adaptation to larval crowding in fruitflies, built on results from 25 38 years of multiple experimental evolution studies on D. melanogaster, is that enhanced 39 competitive ability evolves primarily through increased larval feeding and foraging rate, at 40 the cost of efficiency of food conversion to biomass, and increased larval tolerance to 41 nitrogenous wastes. Thes...
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