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Ovicidal activity of Atalantia monophylla(L)Correa against Spodoptera litura Fab.(Lepidoptera:Noctuidae)

Asian Pacific Journal of Tropical Biomedicine 2012年第12期2卷 987-991页

作者： Kathirvelu Baskar Chellaiah Muthu Gnanaprakasam Antony Raj Selvadurai Kingsley Savarimuthu Ignacimuthu Entomology Research Institute Loyola College PG and Research Department of Advanced Zoology and Biotechnology Loyola College

Objective:To evaluate the efficacy of Atalantia monophylla(A.monophylla)leaf in different solvent crude extracts and fractions against eggs of Spodoptera litura(S.litura).Methods:Hexane,ethyl acetate and chloroform solvent extracts of A.monophylla leaf and 12 fractions from hexane extract were screened at 5.0%t,2.5%,1.0%and 0.5%for crude extracts and 1000,500,250 and 125 mg/kg for fractions against the eggs of S.litura for the ovicidal activity.LC_(50)and LC_(90)were calculated using probit analysis.Results:Hexane crude extract showed maximum ovicidal activity of 61.94%at 5.0%concentration with a correlation value of r^2=0.81,and least LC_(50)value of3.06%.Hexane extract was fractionated using silica gel column chromatography and 12 fractions were obtained.Fraction 9 was active which showed maximum ovicidal activity of 75.61%at 1000mg/kg with the LC_(50)value of 318.65 mg/kg and LC_(90)value of 1473.31 mg/kg.In linear regression analysis,significant and high correlation(r^2=0.81%)was seen between concentration and ovicidal activity of hexane crude extracts and its active frsctien.Conclusions:As per our knowledge,this is the first report for ovicidal activity of A.monophylla against S.litura,A.monophylla could be used for the management of S.litura and other insect pests.

关键词： Atalantia monophylla Crude extracts Fractions Ovicidal activity Spodoptera litura

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Mathematical Model of Seed Dispersal by Frugivorous Birds and Migration Potential of Pinyon and Juniper in Utah

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Applied Mathematics 2015年第9期6卷 1506-1523页

作者： Ram C. Neupane James A. Powell Department of Mathematics and Statistics Utah State University Logan USA Department of Biology Utah State University Logan USA

Seed dispersal of juniper and pinyon is a process in which frugivorous birds play an important role. Birds either consume and digest seeds or carry and cache them at some distance from the source tree. These transported and settled seeds can be described by a dispersal kernel, which captures the probability that the seed will move a certain distance by the end of the process. To model active seed dispersal of this nature, we introduce handling time probabilities into the dispersal model to generate a seed digestion kernel. In the limit of no variability in handling time the seed digestion kernel is Gaussian, whereas for uniform variability in handling time the kernel approaches a Laplace distribution. This allows us to standardize spatial movement (diffusion) and handling time (peak settling rate) parameters for all three distributions and compare. Analysis of the tails indicates that the seed digestion kernel decays at a rate intermediate between Gaussian and Laplace seed kernels. Using this seed digestion kernel, we create an invasion model to estimate the speed at which juniper and pinyon forest boundaries move. We find that the speed of seed invasion corresponding to the digestion kernel was faster than seeds resulting from Laplace and Gaussian kernels for more rapidly digested seeds. For longer handling times the speeds are bounded between the Laplace (faster) and Gaussian (slower) speeds. Using parameter values from the literature we evaluate the migration potential of pinyon and juniper, finding that pinyon may be able to migrate up to two orders of magnitude more rapidly, consistent with observations of pine migration during the Holocene.

关键词： Dispersal Kernel Invasion Speed Seed Handling Time Pinus monophylla Juniperus osteosperma

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