scholarly journals Fungal plant endosymbionts alter life history and reproductive success of aphid predators

2006 ◽  
Vol 273 (1591) ◽  
pp. 1301-1306 ◽  
Author(s):  
Claudio de Sassi ◽  
Christine B Müller ◽  
Jochen Krauss
Keyword(s):  
Rhopalosiphum Padi ◽  
Coccinella Septempunctata ◽  
Fungal Endophyte ◽  
Cereal Aphids ◽  
Negative Effects ◽  
Cascading Effects ◽  
Top Predators ◽  
Significant Damage ◽  
Aphid Predators ◽  
Toxic Alkaloids

Endosymbionts occur in most plant species and may affect interactions among herbivores and their predators through the production of toxic alkaloids. Here, we ask whether effects of mycotoxins produced by the symbiosis of the fungal endophyte Neotyphodium lolii and the grass Lolium perenne are transmitted to the aphidophagous ladybird Coccinella septempunctata when feeding on cereal aphids Rhopalosiphum padi on infected plants. The larval development of coccinellids was extended, while their survival was reduced when feeding exclusively on aphids from infected plants. Ladybirds developing on aphids from infected plants showed reduced fecundity and impaired reproductive performance. Body size and symmetries of ladybird adults were not affected by the endophytes. Consistently strong, negative effects of endophytes on the lifetime performance of ladybirds indicates that mycotoxins are transmitted along food chains, causing significant damage for top predators. Such cascading effects will influence the population dynamics of aphid predators in the long term and could feedback to the primary plant producers.

Impactul inundaţiilor pluviale din Republica Moldova și măsurile de diminuare a lui

2019 ◽  
Author(s):  
Galina Mindru ◽  
Keyword(s):  
Statistical Data ◽  
Negative Effects ◽  
Digital Map ◽  
Republic Of Moldova ◽  
Significant Damage ◽  
Annual Frequency ◽  
The Republic ◽  
Favorable Conditions ◽  
The Impact ◽  
Main Factor

In the Republic of Moldova, the main factor contributing to the floods is the torrential rains from the warm semester of the year, which create favorable conditions for triggering strong, sometimes catastrophic floods in the rivers of the republic, especially in the smaller ones. During the study period, 40 floods with significant damage were recorded in the country, with an annual frequency ranging from 0 to 12 cases. In the administrativeterritorial profile, the damages caused by the aforementioned floods varied greatly. Based on the statistical data, a digital map was developed reflecting the degree of exposure of the territory of the Republic of Moldova in the administrative-territorial aspect to the mentioned risk, expressed by the value of the damages caused. In order to reduce the impact caused by the flood floods, measures have been developed to prevent, reduce and combat the negative effects of that risk.

scholarly journals Life table parameters of the aphid predators Coccinella septempunctata, Ceratomegilla undecimnotata and Propylea quatuordecimpunctata (Coleoptera: Coccinellidae)

2008 ◽  
Vol 105 (3) ◽  
pp. 427-430 ◽  
Author(s):  
Dimitrios C. KONTODIMAS ◽  
Panagiotis G. MILONAS ◽  
George J. STATHAS ◽  
Nickolaos E. PAPANIKOLAOU ◽  
Anna SKOURTI ◽  
...  
Keyword(s):  
Life Table ◽  
Coccinella Septempunctata ◽  
Life Table Parameters ◽  
Propylea Quatuordecimpunctata ◽  
Aphid Predators

Trophic interactions between three species of cereal aphid (Hemiptera: Aphididae) and spring wheat (Poaceae): implications for pest management

2007 ◽  
Vol 139 (6) ◽  
pp. 850-863 ◽  
Author(s):  
Samuel M. Migui ◽  
Robert J. Lamb
Keyword(s):  
Spring Wheat ◽  
Trophic Interactions ◽  
Plant Biomass ◽  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Economic Damage ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Economic Thresholds ◽  
Specific Impact

AbstractThe susceptibilities of genetically diverse Canadian spring wheats, Triticum aestivum L. and Triticum durum Desf., to three aphid species, Rhopalosiphum padi (L.), Sitobion avenae (Fabricius), and Schizaphis graminum (Rondani), were investigated. Trophic interactions measured as changes in biomass of aphids and wheat plants were used to quantify levels of resistance, components of resistance, and impact of aphids on yield. Plants in field cages were infested with small numbers of aphids for 21 days at heading. These plants were usually more suitable for the development of S. avenae and S. graminum than of R. padi. Partial resistance, measured as seed production by infested plants as a proportion of that by a control, varied from 11% to 59% for different aphid species and wheat classes when all wheat plants were infested at the same stage. Cultivars within wheat classes responded similarly to each of the aphid species. None of the wheat cultivars showed agriculturally effective levels of antibiosis. The specific impact of each aphid species and wheat class varied from 5 to 15 mg of plant biomass lost for each milligram of biomass gained by the aphids. Canadian Western Red Spring wheat had a lower specific impact and therefore was more tolerant to aphids than the other two classes, but not tolerant enough to avoid economic damage at the aphid densities observed. Plants did not compensate for feeding damage after aphid feeding ceased, based on the higher specific impacts observed for mature plants than for plants that were heading. The interactions between aphids and plants show that current economic thresholds probably underestimate the damage caused by cereal aphids to Canadian spring wheat.

scholarly journals Virulence of Two Entomophthoralean Fungi, Pandora neoaphidis and Entomophthora planchoniana, to Their Conspecific (Sitobion avenae) and Heterospecific (Rhopalosiphum padi) Aphid Hosts

Insects ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 54 ◽  
Author(s):  
Ibtissem Ben Fekih ◽  
Annette Bruun Jensen ◽  
Sonia Boukhris-Bouhachem ◽  
Gabor Pozsgai ◽  
Salah Rezgui ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Sitobion Avenae ◽  
Cereal Aphids ◽  
Infection Level ◽  
Initial Exposure ◽  
Pandora Neoaphidis ◽  
First Time ◽  
Aphid Host

Pandora neoaphidis and Entomophthora planchoniana (phylum Entomophthoromycota) are important fungal pathogens on cereal aphids, Sitobion avenae and Rhopalosiphum padi. Here, we evaluated and compared for the first time the virulence of these two fungi, both produced in S. avenae cadavers, against the two aphid species subjected to the same exposure. Two laboratory bioassays were carried out using a method imitating entomophthoralean transmission in the field. Healthy colonies of the two aphid species were exposed to the same conidial shower of P. neoaphidis or E. planchoniana, in both cases from a cadaver of S. avenae. The experiments were performed under LD 18:6 h at 21 °C and a successful transmission was monitored for a period of nine days after initial exposure. Susceptibility of both S. avenae and R. padi to fungal infection showed a sigmoid trend. The fitted nonlinear model showed that the conspecific host, S. avenae, was more susceptible to E. planchoniana infection than the heterospecific host R. padi, was. In the case of P. neoaphidis, LT50 for S. avenae was 5.0 days compared to 5.9 days for R. padi. For E. planchoniana, the LT50 for S. avenae was 4.9 days, while the measured infection level in R. padi was always below 50 percent. Our results suggest that transmission from conspecific aphid host to heterospecific aphid host can occur in the field, but with expected highest transmission success to the conspecific host.

scholarly journals Loss of top-down biotic interactions changes the relative benefits for obligate mutualists

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182501 ◽  
Author(s):  
Rong Wang ◽  
Xiao-Yong Chen ◽  
Yan Chen ◽  
Gang Wang ◽  
Derek W. Dunn ◽  
...  
Keyword(s):  
Biotic Interactions ◽  
Trophic Levels ◽  
Fig Wasp ◽  
Negative Effects ◽  
Top Down ◽  
Top Predators ◽  
Natural Range ◽  
Obligate Mutualism ◽  
The Stability ◽  
Food Web Complexity

The collapse of mutualisms owing to anthropogenic changes is contributing to losses of biodiversity. Top predators can regulate biotic interactions between species at lower trophic levels and may contribute to the stability of such mutualisms, but they are particularly likely to be lost after disturbance of communities. We focused on the mutualism between the fig tree Ficus microcarpa and its host-specific pollinator fig wasp and compared the benefits accrued by the mutualists in natural and translocated areas of distribution. Parasitoids of the pollinator were rare or absent outside the natural range of the mutualists, where the relative benefits the mutualists gained from their interaction were changed significantly away from the plant's natural range owing to reduced seed production rather than increased numbers of pollinator offspring. Furthermore, in the absence of the negative effects of its parasitoids, we detected an oviposition range expansion by the pollinator, with the use of a wider range of ovules that could otherwise have generated seeds. Loss of top-down control has therefore resulted in a change in the balance of reciprocal benefits that underpins this obligate mutualism, emphasizing the value of maintaining food web complexity in the Anthropocene.

Application of the FAO-recommended method for detecting insecticide resistance in Aphis jabae Scopoli, Sitobion avenae (F.), Metopolophium dirhodum (Walker) and Rhopalosiphum padi (L.) (Hemiptera: Aphididae)

1983 ◽  
Vol 73 (1) ◽  
pp. 107-115 ◽  
Author(s):  
M. F. Stribley ◽  
G. D. MOORES ◽  
A. L. DEVONSHIRE ◽  
R. M. SAWICKI
Keyword(s):  
Insecticide Resistance ◽  
Rhopalosiphum Padi ◽  
Sitobion Avenae ◽  
Aphis Fabae ◽  
Cereal Aphids ◽  
Metopolophium Dirhodum ◽  
Large Numbers ◽  
The Uk ◽  
Dip Test

AbstractBaseline toxicity measurements established discriminating concentrations of pirimicarb and demeton-S-methyl guaranteed to kill susceptible examples of Aphis fabae Scop., Sitobion avenae (F.), Metopolophium dirhodum (Wlk.) and Rhopalosiphum padi (L.) in the dip-test, the FAO-recommended method for detecting resistance in aphids. There was no evidence for resistance to either insecticide in field-collected populations of aphids from various parts of the UK or amongst variants of S. avenae characterised by staining their esterases after electrophoresis. New, simple techniques for rearing large numbers of colonies of cereal aphids are described.

scholarly journals Transgenic Winter Wheat Expressing the Sucrose Transporter HvSUT1 from Barley does not Affect Aphid Performance

Insects ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 388 ◽  
Author(s):  
Yang ◽  
Kloos ◽  
Mora-Ramírez ◽  
Romeis ◽  
Brunner ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Sucrose Transporter ◽  
Yield Potential ◽  
Cereal Aphids ◽  
Biotic Stresses ◽  
Transgenic Lines ◽  
Negative Impacts ◽  
Parental Cultivar

Winter wheat expressing the sucrose transporter HvSUT1 from barley (HOSUT) has an increased yield potential. Genetic engineering should improve cultivars without increasing susceptibility to biotic stresses or causing negative impacts on ecosystem services. We studied the effects of HOSUT wheat on cereal aphids that feed on the sugar-rich phloem sap. Three HOSUT winter wheat lines, their conventional parental cultivar Certo, and three conventional cultivars were used. Clip cage experiments in the greenhouse showed no differences in life-table parameters of Rhopalosiphum padi and Sitobion avenae (Hemiptera: Aphididae) on transgenic lines compared to Certo, except higher fecundity of S. avenae on one HOSUT line. Population development of both aphid species over three weeks on caged flowering tillers did not reveal differences between the HOSUT lines and Certo. When aphids were monitored in a Swiss field study over two years, no differences between HOSUT lines and Certo were observed. We conclude that HOSUT wheat did not have consistent effects on aphids compared to the parental cultivar and measured parameters were generally in the range observed for the conventional winter wheat cultivars. Thus, HOSUT wheat is unlikely to suffer from increased aphid damage.

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