نتایج جستجو برای: larval population density

تعداد نتایج: 1092977  

2017
Christopher Doropoulos Nicolas R Evensen Luis A Gómez-Lemos Russell C Babcock

Population growth involves demographic bottlenecks that regulate recruitment success during various early life-history stages. The success of each early life-history stage can vary in response to population density, interacting with intrinsic (e.g. behavioural) and environmental (e.g. competition, predation) factors. Here, we used the common reef-building coral Acropora millepora to investigate...

Journal: :Ecological applications : a publication of the Ecological Society of America 2012
J D Willson W A Hopkins C M Bergeron B D Todd

Concern that environmental contaminants contribute to global amphibian population declines has prompted extensive experimental investigation, but individual-level experimental results have seldom been translated to population-level processes. We used our research on the effects of mercury (Hg) on American toads (Bufo americanus) as a model for bridging the gap between individual-level contamina...

2006
Kevin D. Lafferty

I investigated the prediction that parasitic castrators can reduce host population density. A survey of the salt marsh snail Cerithidea californica suggested a negative association between snail density and the prevalence of larval trematodes which castrate parasitized snails. Field experiments were conducted to determine the mechanisms by which larval trematodes might affect snail populat ion~...

2011
Angela R Amarillo-Suárez R Craig Stillwell Charles W Fox

Body size varies considerably among species and among populations within species, exhibiting many repeatable patterns. However, which sources of selection generate geographic patterns, and which components of fitness mediate evolution of body size, are not well understood. For many animals, resource quality and intraspecific competition may mediate selection on body size producing large-scale g...

2012
D. T. Tyler Flockhart Tara G. Martin D. Ryan Norris

A central goal of population ecology is to identify the factors that regulate population growth. Monarch butterflies (Danaus plexippus) in eastern North America re-colonize the breeding range over several generations that result in population densities that vary across space and time during the breeding season. We used laboratory experiments to measure the strength of density-dependent intraspe...

2017
Suellen de Oliveira Daniel Antunes Maciel Villela Fernando Braga Stehling Dias Luciano Andrade Moreira Rafael Maciel de Freitas

BACKGROUND Wolbachia has been deployed in several countries to reduce transmission of dengue, Zika and chikungunya viruses. During releases, Wolbachia-infected females are likely to lay their eggs in local available breeding sites, which might already be colonized by local Aedes sp. mosquitoes. Therefore, there is an urgent need to estimate the deleterious effects of intra and interspecific lar...

2012
B. J. Rothschild T. R. Osborn T. D. Dickey D. M. Farmer

Larval mortality is an important component of recruitment variability. To understand the mechanisms affecting larval mortality, it is necessary to take into account the nonlinear interactions involved in density-dependent population dynamics and the physical environment at scales of motion comparable with larval feeding scales. This paper develops a framework for further analysis by describing ...

Journal: :Journal of Insect Science 2004
Melanie Gibbs Lesley A. Lace Martin J. Jones Allen J. Moore

In insects, the outcome of intraspecific competition for food during development depends primarily upon larval density and larval sex, but effects will also depend on the particular trait under consideration and the species under study. Experimental manipulations of larval densities of a Madeiran population of the speckled wood butterfly Pararge aegeria confirmed that intraspecific competition ...

The larval community of coral reef fishes in the Red Sea was studied in coastal and offshore sites to determine the effects of the exposure to waves and currents and the distance from the shore in structuring the larval fish community. Plankton sampling from inshore and offshore sites and the exposed and sheltered sides of the reefs resulted in the collection of 2048 larvae representing 49 diff...

Journal: :journal of agricultural science and technology 2010
a. a. pourmirza

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 ...

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