Response by coccinellids to spatial variation in cereal aphid density

2000 ◽  
Vol 42 (1) ◽  
pp. 81-90 ◽  
Author(s):  
N. Elliott ◽  
R. W. Kieckhefer
Keyword(s):  
Spatial Variation ◽  
Cereal Aphid ◽  
Aphid Density

scholarly journals Comparison of Field Population Growths of Three Cereal Aphid Species on Winter Wheat

2011 ◽  
Vol 39 (No. 2) ◽  
pp. 61-64 ◽  
Author(s):  
V. Jarošík ◽  
A. Honěk ◽  
A. Tichopád
Keyword(s):  
Winter Wheat ◽  
Rhopalosiphum Padi ◽  
Intrinsic Rate ◽  
Aphid Species ◽  
Population Increase ◽  
Intrinsic Rate Of Increase ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Rate Of Increase

Population growths of three aphid species colonising winter wheat stands, Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae, were analysed by regression method. The calculations were based on counts in 268 winter wheat plots at 3 or 7 day intervals over 10 (leaves) or 6 (ears) years. The population dynamics of a particular species differed widely between years. Density independent exponential growth of the population was most common, but its rate differed significantly between species, and for S. avenae also between populations on leaves and ears, on which the populations grew fastest. Field estimates of the intrinsic rate of increase derived from the exponential growths ranged between 0.010–0.026 in M. dirhodum, 0.0071–0.011 in R. padi, and between 0.00078–0.0061 and 0.0015–0.13 in S. avenae on leaves and ears, respectively. In the populations with the most vigorous population growth, S. avenae on ears and M. dirhodum on leaves, the rate of population increase significantly decreased with increasing aphid density.  

A GENERAL METHOD FOR ESTIMATING CEREAL APHID POPULATIONS IN SMALL GRAIN FIELDS BASED ON FREQUENCY OF OCCURRENCE

1995 ◽  
Vol 127 (1) ◽  
pp. 59-63 ◽  
Author(s):  
G.L. Hein ◽  
N.C. Elliott ◽  
G.J. Michels ◽  
R.W. Kieckhefer
Keyword(s):  
Weighted Average ◽  
Aphid Species ◽  
Parameter Estimates ◽  
Single Model ◽  
Cereal Aphid ◽  
Grain Aphid ◽  
Aphid Density ◽  
Single Set ◽  
General Method ◽  
Aphid Populations

AbstractSimilarities in population parameters among aphid species led us to investigate the potential for a single set of parameters that can be used to develop a ‘generic’ sampling plan for multiple small grain aphid species. A weighted average for the slope and intercept used to relate the proportion of infested tillers to the number of aphids per tiller was determined from the data in 15 published reports. These average parameter estimates were used to predict the number of aphids per tiller in 48 wheat fields sampled for four aphid species. The predicted estimates were regressed on the observed estimates with neither slopes nor intercepts differing significantly from one or zero, respectively. Therefore, it appears the single model is adequate for predicting aphid density for the aphid species tested.

scholarly journals Influence of Plant Diversity on the Numerical Response ofEriopis connexa(Coleoptera: Coccinellidae) to Changes in Cereal Aphid Density in Wheat Crops

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
María C. Tulli ◽  
Dora M. Carmona ◽  
Ana M. Vincini
Keyword(s):  
Plant Diversity ◽  
Aphid Species ◽  
Linear Increase ◽  
Numerical Response ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Higher Plant ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Eriopis Connexa

Cereal aphids cause economic injury to wheat crops. In Argentina,Eriopis connexais an indigenous ladybird. In the present study, the numerical response ofE. connexato changes in aphid density on wheat crops with high and low plant diversity was investigated. The study was carried out in Balcarce, Buenos Aires, Argentina, from September to December 2007 and 2008, on two wheat crops with either a higher plant diversity (HPD) with refuge strips or a lower plant diversity (LPD) without refuge strips. Crops were sampled every week and the abundance of aphids andE. connexawas recorded. The dominant aphid species wereSchizaphis graminum, Metopolophium dirhodum,andSitobion avenae.Eriopis connexashowed a linear increase in the numerical response to an increase in aphid density, which varied in space and time. The abundance ofE. connexaincreased in relation to the crop development and aphid population and was higher in the HPD than in the LPD system. This predator increased its reproductive numerical response only in 2008, with a significant liner response in the HPD system. This suggests that the potential ofE. connexaas a predator of cereal aphids also increases directly in proportion to landscape vegetal diversity.

Comparing growth patterns among field populations of cereal aphids reveals factors limiting their maximum abundance

2006 ◽  
Vol 96 (3) ◽  
pp. 269-277 ◽  
Author(s):  
A. Honek ◽  
V. Jarosik ◽  
A.F.G. Dixon
Keyword(s):  
Exponential Growth ◽  
Rhopalosiphum Padi ◽  
Growth Patterns ◽  
Aphid Population ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Density Dependent ◽  
Maximum Abundance ◽  
Aphid Density

AbstractCereal stands in central Europe are commonly infested with three species of aphids that may become serious pests. With increasing abundance, the proportion of a particular species in the total aphid population may remain constant, suggesting a density-independent exponential growth, or the proportion can change, suggesting density-dependent constraints on growth. The constraints that affect particular species, and thus their relative abundance, were studied. The proportionality between maximum abundances of the cereal aphids was studied using a 10-year census of the numbers of aphids infesting 268 winter wheat plots. For two species their abundance on leaves and ears was compared. With increasing aphid density the maximum abundance of Rhopalosiphum padi (Linnaeus) remained proportional, but not that of Sitobion avenae (Fabricius), which was constrained by the smaller surface area of ears compared to leaves. There was no evidence of inter-specific competition. Maximum abundance of R. padi and Metopolophium dirhodum (Walker) on leaves did not change proportionally as the proportion of M. dirhodum decreased with increasing overall aphid density. This decrease was probably caused by the restricted distribution of M. dirhodum, which is confined to leaves, where space is limiting. No change in proportion between populations was detected when the average densities were below 0.54 aphids per leaf or ear. Non-proportional relationships between aphid populations appeared to be due to spatial constraints, acting upon the more abundant population. Detecting the limitation of population growth can help with the assessment of when density-independent exponential growth is limited by density-dependent factors. This information may help in the development of models of cereal aphid population dynamics.

Assessment of methods for estimating the numbers of aphids (Hemiptera: Aphididae) in Cereals

1982 ◽  
Vol 72 (4) ◽  
pp. 675-685 ◽  
Author(s):  
Alan M. Dewar ◽  
Godfrey J. Dean ◽  
Ray Cannon
Keyword(s):  
Field Studies ◽  
Accurate Method ◽  
Sitobion Avenae ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Very High ◽  
Vacuum Sampling

AbstractVisual counting was found to be the most accurate method of estimating cereal aphid numbers in field studies in England. Vacuum sampling decreased in efficiency as aphid density increased, but could be a useful alternative to visual counts at very low aphid densities when the latter became too time-consuming. Cutting tillers for later washing in the laboratory was less efficient than visual counting as aphids, especially Metopolophium dirhodum (Wlk.), fell off the plants during sampling, but this method was useful in determining the proportion of different morphs of Sitobion avenae (F.) present at very high densities.

Digital representation of spatial variation of multivariate landscape data

2006 ◽  
Vol 7 (2) ◽  
pp. 181-188 ◽  
Author(s):  
A. Altobelli ◽  
E. Bressan ◽  
E. Feoli ◽  
P. Ganis ◽  
F. Martini
Keyword(s):  
Spatial Variation ◽  
Digital Representation

Function of coprophagous beetles (Coleoptera: Scarabaeidae, Geotrupidae, Hydrophilidae) in cattle pastures inferred from pitfall trapping data

2010 ◽  
Vol 27 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Martin Šlachta ◽  
Jan Frelich ◽  
Tomáš Tonka
Keyword(s):  
Seasonal Variation ◽  
Spatial Variation ◽  
Dry Weight ◽  
Seasonal Distribution ◽  
The Other ◽  
Pitfall Trapping ◽  
Other Hand ◽  
Nested Anova ◽  
Species Groups ◽  
Dung Decomposition

Function of coprophagous beetles (Coleoptera: Scarabaeidae, Geotrupidae, Hydrophilidae) in cattle pastures inferred from pitfall trapping dataAn analysis of data on the dry weight biomass of coprophagous beetles in standardized dung (4.5 l) was conducted in order to characterize the spatial and the seasonal distribution of the beetles' biomass in cattle pastures and to elucidate their function in dung decomposition. Nested Anova with factors of farm, site (nested in farm), seasonal period and year was used to evaluate the effect of these factors on the biomass of four functional species groups: the dung dwellers ofScarabaeidae(subfamilyAphodiinae), the dung dwellers ofHydrophilidae, the small tunnellers ofScarabaeidae(subfamilyCoprinae) and the large tunnellers ofGeotrupidae. The spatial variation of biomass (between the sites and the farms) was insignificant (P>0.05) in the two dung-dweller groups and in the large-tunnellers group. On the other hand, a significant (P<0.05) seasonal variation of biomass was found in all but the large tunneller group. In dung dwellers, the spring biomass was formed mainly by two species,Aphodius prodromusandA. sphacelatus. In summer, most of the biomass was accounted for bySphaeridium lunatum, S. scarabaeoidesandA. rufipes. In the two tunneller groups,Onthophagus fracticornis, Geotrupes stercorariusandG. spinigerformed a majority of the biomass in dung.

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