‘Bottom-up’ effects in a tritrophic plant–aphid–parasitoid system: Why being the perfect host can have its disadvantages

2019 ◽  
Vol 109 (6) ◽  
pp. 831-839
Author(s):  
M. Mehrparvar ◽  
A. Rajaei ◽  
M. Rokni ◽  
A. Balog ◽  
H.D. Loxdale
Keyword(s):  
Host Plant ◽  
Block Design ◽  
Aphid Species ◽  
Trophic Levels ◽  
Context Dependency ◽  
Diaeretiella Rapae ◽  
Host Specialization ◽  
Aphid Parasitoid ◽  
Cabbage Aphid ◽  
Genotype Effect

AbstractIn this study the host plant genotype effect on cabbage aphid, Brevicoryne brassicae (L.)(Hemiptera: Aphididae) preference and performance, the effect of aphid genotype on parasitoids performance, as well as the indirect effects of plant genotypes on aphid parasitoid performance, were tested using different population samples of the aphid and its primary endoparasitoid wasp, Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae). Experiments were run as fully-factorial randomized block design in a greenhouse. Accordingly, host plant cultivar had significant effects on the total number of aphids and aphid-load whilst the fitness of the aphid genotypes were also influenced by plant cultivar. The effect of parasitism on cabbage aphids was significantly different between plant cultivars. Overall, the results revealed that cabbage aphid is under different selective pressures arising from both higher (parasitoid) and lower (host plant cultivar) trophic levels. The host plant cultivar had a significant effect on both aphid fitness and parasitism rate on particular aphid genotypes. This indicates that host-plant-adapted aphid species can create much context-dependency in the nature and strength of ‘fitness benefits parasitism’, which may in turn alter the costs and benefits of host specialization.

Hieracium-associated aphid parasitoid guilds (Hymenoptera: Braconidae: Aphidiinae) in Europe

Zootaxa ◽  
2008 ◽  
Vol 1781 (1) ◽  
pp. 20 ◽  
Author(s):  
ŠELJKO TOMANOVIĆ ◽  
PETR STARÝ ◽  
NICKOLAS G. KAVALLIERATOS ◽  
ANDJELJKO PETROVIĆ ◽  
MARIJAN NIKETIĆ ◽  
...  
Keyword(s):  
Host Plant ◽  
Aphid Species ◽  
Taxonomic Position ◽  
New Host ◽  
Aphid Parasitoid ◽  
Brachycaudus Helichrysi

Eleven aphidiine braconid species are associated with 10 aphid species to form over 50 tritrophic associations in Europe. The host aphids belong to five genera, Aphis L., Brachycaudus Van der Goot, Hyperomyzus Börner, Nasonovia Mordvilko, and Uroleucon Mordvilko, and feed on 11 Hieracium species. Five new host plant records are reported. The associated aphidiine guilds are linked with the taxonomic position of the host aphids. Host aphids such as Brachycaudus helichrysi (Kaltenbach) and Uroleucon spp. are broadly oligophagous, but Nasonovia spp., Aphis hieracii Schrank, and Hyperomyzus hieracii (Börner) are specific mainly to Hieracium and related plants. A key for the identification of aphidiine species associated with aphids on Hieracium plants in Europe is provided.

Host stage preference and performance of the aphid parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) on Brevicoryne brassicae and Lipaphis pseudobrassicae (Hemiptera: Aphididae)

2016 ◽  
Vol 36 (01) ◽  
pp. 10-21 ◽  
Author(s):  
Sylvia W.R. Khakasa ◽  
Samira A. Mohamed ◽  
Zipporah O. Lagat ◽  
Fathiya M. Khamis ◽  
Chrysantus M. Tanga
Keyword(s):  
Host Species ◽  
Oviposition Preference ◽  
Aphid Species ◽  
Brevicoryne Brassicae ◽  
Diaeretiella Rapae ◽  
Pest Species ◽  
Aphid Parasitoid ◽  
Significant Difference ◽  
Host Stage ◽  
And Performance

We assessed the host stage preference and performance of the aphid parasitoidDiaeretiella rapae(McIntosh) on two aphid species,Brevicoryne brassicae(L.) andLipaphis pseudobrassicae(Davis). Although the parasitoid parasitized all nymphal instars of both aphid species, it showed a higher oviposition preference for 2nd (48.2 ± 7.74%) and 3rd (41.0 ± 7.82%) instars ofL. pseudobrassicae, and for the 3rd (40.0 ± 4.59%) instar ofB. brassicae. Across the host species, there was no significant difference in parasitoid preference between the 3rd and 4th instars, while 1st and 2nd instars ofL. pseudobrassicaewere significantly more preferred than their counterparts (B. brassicae). Days to mummification among different instars of the same host was not significantly different when the parasitoid was reared onB. brassicae, whereas this was highest on the 2nd, 3rd and 4th instars ofL. pseudobrassicae. Number of mummies was also significantly different among the nymphal instars of both host species and between the two host species for the 1st and 2nd instars. In terms of body size, femaleD. rapaereared onL. pseudobrassicaewere significantly larger than those reared onB. brassicae. We discuss the findings in the context of laboratory mass rearing ofD. rapaeand its potential as a biological control agent for both aphid pest species.

Highly conserved genes expressed in aphid saliva are candidates for host plant adaptation in Aphis gossypii

2020 ◽  
Author(s):  
Nathalie Boissot ◽  
Leslie Dutartre-Fricaux ◽  
Coralie Beucher ◽  
Flavie Vanlerberghe
Keyword(s):  
Host Plant ◽  
Acyrthosiphon Pisum ◽  
Aphis Gossypii ◽  
Aphid Species ◽  
Host Specialization ◽  
Salivary Proteins ◽  
Single Family ◽  
Host Plant Adaptation ◽  
Conserved Genes ◽  
Compatible Interactions

Abstract BackgroundAphids are major crop pests, most species attacking crops specialize on a narrow range of plant species from a single family. By contrast, Aphis gossypii is a highly polyphagous species, for which host races specializing on particular crops have been clearly described. Salivary components, which aphids inject into the phloem via their stylets, play a key role in establishing compatible interactions between plants and aphids, and are probably involved in specialization.ResultsWe used the extensive resources available for Myzus persicae and Acyrthosiphon pisum to identify putative salivary proteins expressed in Aphis gossypii, despite the lack of genomic resources for this species. In silico, we identified 51 putative salivary proteins; we focused on 17 genes with orthologs in at least one aphid species, assuming that some of the conserved genes expressed in salivary glands are involved in host specialization. We amplified and sequenced 10 coding sequences in full, from 17 clones of Aphis gossypii specialising on plants from Malvaceae, Cucurbitaceae or Solanaceae. We reconstructed the phylogenetic tree for these genes, on which we identified a clade corresponding to all clones specializing on cucurbits. Three of these genes were under positive selection.ConclusionsFull adaptation to a particular host plant may require a combination of alleles at quantitative trait loci in aphids. The three genes we identified could potentially be part of a cocktail of effectors manipulating the immune system of cucurbits and therefore responsible for A. gossypii specialization on that plant family.

Ecological specialization in Diaeretiella rapae (Hymenoptera: Braconidae: Aphidiinae) on aphid species from wild and cultivated plants

2017 ◽  
Vol 108 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Y. Navasse ◽  
S.A.P. Derocles ◽  
M. Plantegenest ◽  
A. Le Ralec
Keyword(s):  
Reproductive Isolation ◽  
Control Strategies ◽  
Chenopodium Album ◽  
Aphid Species ◽  
Diaeretiella Rapae ◽  
Cultivated Plants ◽  
Ecological Specialization ◽  
Aphid Parasitoid ◽  
Genetic Studies

AbstractDiaeretiella rapae is an aphid parasitoid with potential for use in biological control strategies. However, several recent genetic studies have challenged the long held view that it is a generalist parasitoid. We investigated its ecological specialization and ability to use resources in cultivated and uncultivated areas. Ecological specialization would reduce its ability to exploit the diversity of aphid species, particularly in uncultivated areas, and to control pest aphids. Four D. rapae strains were studied, three reared on pest aphids on Brassicaceae and one strain on a non-pest aphid on Chenopodiaceae. For each strain, we performed host-switching experiments, with a total of six aphid species, five of which D. rapae parasitizes in France. We tested cross-breeding ability between strains to detect potential reproductive isolation linked to aphid host species in D. rapae. The strain reared on non-pest aphids was able to develop on aphid species from both cultivated and uncultivated plants. The strains reared on pest aphids, however, exclusively parasitized aphid species on cultivated Brassicaceae. In addition, reproductive isolation was detected between strains from uncultivated and cultivated plants. Thus, the D. rapae populations examined here appear to be showing ecological specialization or they may even be composed of a complex of cryptic species related to the aphid hosts. The role of Chenopodium album as a reservoir for D. rapae, by providing a habitat for non-pest aphids on which it can feed, appears to be severely limited, and thus its efficiency to maintain local populations of D. rapae in the vicinity of crops is questionable.

scholarly journals Hymenopteran Parasitoids of Aphid Pests within Australian Grain Production Landscapes

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 44
Author(s):  
Samantha E. Ward ◽  
Paul A. Umina ◽  
Sarina Macfadyen ◽  
Ary A. Hoffmann
Keyword(s):  
Aphid Species ◽  
Crop Growth ◽  
Diaeretiella Rapae ◽  
Field Variation ◽  
Grain Crops ◽  
Growing Seasons ◽  
Crop Type ◽  
Eastern Australia ◽  
Crop Growth Stage ◽  
Hymenopteran Parasitoids

In grain crops, aphids are important pests, but they can be suppressed by hymenopteran parasitoids. A challenge in incorporating parasitoids into Integrated Pest Management (IPM) programs, however, is that parasitoid numbers can be low during periods within the season when aphids are most damaging. Understanding the population dynamics of key aphid species and their parasitoids is central to ameliorating this problem. To examine the composition and seasonal trends of both aphid and parasitoid populations in south-eastern Australia, samples were taken throughout the winter growing seasons of 2017 and 2018 in 28 fields of wheat and canola. Myzus persicae (Sulzer) was the most abundant aphid species, particularly within canola crops. Across all fields, aphid populations remained relatively low during the early stages of crop growth and increased as the season progressed. Seasonal patterns were consistent across sites, due to climate, crop growth stage, and interactions between these factors. For canola, field edges did not appear to act as reservoirs for either aphids or parasitoids, as there was little overlap in the community composition of either, but for wheat there was much similarity. This is likely due to the presence of similar host plants within field edges and the neighbouring crop, enabling the same aphid species to persist within both areas. Diaeretiella rapae (M’Intosh) was the most common parasitoid across our study, particularly in canola, yet was present only in low abundance at field edges. The most common parasitoid in wheat fields was Aphidius matricariae (Haliday), with field edges likely acting as a reservoir for this species. Secondary parasitoid numbers were consistently low across our study. Differences in parasitoid species composition are discussed in relation to crop type, inter-field variation, and aphid host. The results highlight potential focal management areas and parasitoids that could help control aphid pests within grain crops.

scholarly journals Genotype X Environment Interaction of Food Barley

2015 ◽  
Vol 21 ◽  
pp. 41-48
Author(s):  
Gebremedhin Welu
Keyword(s):  
Grain Yield ◽  
Block Design ◽  
Genotype X Environment Interaction ◽  
Environment Interaction ◽  
Genotype X Environment ◽  
Genotype Effect ◽  
Environment Effects ◽  
Randomized Complete Block Design ◽  
Barley Genotypes

The objective of this experiment was to estimate the magnitude of genotype X environment interaction on grain yield and yield related traits. Twelve varieties of food barley were included in the study planted in randomized complete block design with three replications. The ANOVA of combined and individual location revealed significant differences among the food barley genotypes for grain yield and other traits. The results of ANOVA for grain yield showed highly significant (p≤0.01) differences among genotypes evaluated for grain yield at Maychew and significant (p≤0.05) differences in Korem, Alage and Mugulat. The ANOVA over locations showed a highly significant (p≤0.01) variation for the genotype effect, environment effects, genotype X environment interaction (GEI) effect and significant (p≤0.05) variation for GEI effect of yield and for most of the yield related traits of food barley genotypes. Haftysene, Yidogit, Estayish and Basso were the genotypes with relatively high mean grain yield across all locations and they are highly performing genotypes to the area. Among locations, the highest mean grain yield was recorded at Korem and it was a suited environment to all the genotypes whereas Mugulat is unfavoured one. ECOPRINT 21: 41-48, 2014DOI: http://dx.doi.org/10.3126/eco.v21i0.11903

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