scholarly journals The use of salivary α-amylase as an evolutionary solution to host selection in parasitoids

2017 ◽  
Author(s):  
Gladys Bichang’a ◽  
Jean-Luc Da Lage ◽  
Claire-Marie Mailhan ◽  
Frédéric Marion-Poll ◽  
Claire Capdevielle-Dulac ◽  
...  
Keyword(s):  
Host Selection ◽  
Host Recognition ◽  
Host Feeding ◽  
Antennal Sensilla ◽  
Oral Secretions ◽  
Behavioral Observations ◽  
Selection Processes ◽  
Feeding Process ◽  
First Contact ◽  
Gustatory Neurons

AbstractForaging parasitoids use chemical signals in host recognition and selection processes. Thereby, chemicals from the herbivore hosts play a crucial role. When different herbivores are present in the same plant or field, the perception of specific volatiles and contact compounds emitted from the host itself enable the parasitoids both to differentiate between hosts and non-hosts and to estimate the health status of its host. During the host feeding process, contact between the parasitoid and its host is very crucial, and oral secretions from the host play a key role during the first contact for such evaluation by the parasitoid. Using an integration of behavioral observations, biochemical and sensory physiological approaches we demonstrate that female parasitoids of Cotesia flavipes recognize their host and oviposit in reaction to an α-amylase, which is present in the oral secretions of the larvae of their host, Chilo partellus. This activity was also mediated by a purified α-amylase synthetized from Drosophila melanogaster. Using this synthetized enzyme, we further demonstrate that the conformation of the enzyme rather than its catalytic site is responsible for this activity. This enzyme is activating gustatory neurons of the terminal antennal sensilla chaetica of C. flavipes females. α-amylases are therefore good candidates for an evolutionary solution to host selection in parasitoids, thus opening new avenues for investigations in hosts-parasitoids interactions.

Host selection behavior of the host-feeding parasitoid Necremnus tutae on Tuta absoluta

2021 ◽  
Author(s):  
Yibo Zhang ◽  
Xiaocao Tian ◽  
Hao Wang ◽  
Cristina Casteňé ◽  
Judit Arnó ◽  
...  
Keyword(s):  
Host Selection ◽  
Tuta Absoluta ◽  
Host Feeding ◽  
Host Selection Behavior ◽  
Selection Behavior

scholarly journals Agricultural management and plant selection interactively affect rhizosphere microbial community structure and nitrogen cycling

Microbiome ◽  
2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jennifer E. Schmidt ◽  
Angela D. Kent ◽  
Vanessa L. Brisson ◽  
Amélie C. M. Gaudin
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Nitrogen Cycling ◽  
Community Composition ◽  
Network Structure ◽  
Host Selection ◽  
Agricultural Management ◽  
Plant Selection ◽  
Selection Processes ◽  
Rhizosphere Microbial Community

Abstract Background Rhizosphere microbial communities are key regulators of plant performance, yet few studies have assessed the impact of different management approaches on the rhizosphere microbiomes of major crops. Rhizosphere microbial communities are shaped by interactions between agricultural management and host selection processes, but studies often consider these factors individually rather than in combination. We tested the impacts of management (M) and rhizosphere effects (R) on microbial community structure and co-occurrence networks of maize roots collected from long-term conventionally and organically managed maize-tomato agroecosystems. We also explored the interaction between these factors (M × R) and how it impacts rhizosphere microbial diversity and composition, differential abundance, indicator taxa, co-occurrence network structure, and microbial nitrogen-cycling processes. Results Host selection processes moderate the influence of agricultural management on rhizosphere microbial communities, although bacteria and fungi respond differently to plant selection and agricultural management. We found that plants recruit management-system-specific taxa and shift N-cycling pathways in the rhizosphere, distinguishing this soil compartment from bulk soil. Rhizosphere microbiomes from conventional and organic systems were more similar in diversity and network structure than communities from their respective bulk soils, and community composition was affected by both M and R effects. In contrast, fungal community composition was affected only by management, and network structure only by plant selection. Quantification of six nitrogen-cycling genes (nifH, amoA [bacterial and archaeal], nirK, nrfA, and nosZ) revealed that only nosZ abundance was affected by management and was higher in the organic system. Conclusions Plant selection interacts with conventional and organic management practices to shape rhizosphere microbial community composition, co-occurrence patterns, and at least one nitrogen-cycling process. Reframing research priorities to better understand adaptive plant-microbe feedbacks and include roots as a significant moderating influence of management outcomes could help guide plant-oriented strategies to improve productivity and agroecosystem sustainability.

Volatiles mediate host-selection in the corn hoppers Dalbulus maidis (Hemiptera: Cicadellidae) and Peregrinus maidis (Hemiptera: Delphacidae)

2019 ◽  
Vol 109 (05) ◽  
pp. 633-642 ◽  
Author(s):  
M.V. Coll Aráoz ◽  
V.G. Jacobi ◽  
P.C. Fernandez ◽  
E. Luft Albarracin ◽  
E.G. Virla ◽  
...  
Keyword(s):  
Host Selection ◽  
Visual Cues ◽  
Olfactory Cues ◽  
Host Recognition ◽  
Gas Chromatography Mass Spectrometry ◽  
Dalbulus Maidis ◽  
Peregrinus Maidis ◽  
Olfactory Responses ◽  
Phototactic Response ◽  
Volatile Cues

AbstractVolatile organic compounds (VOCs) released by plants are generally involved in host recognition and host selection for many phytophagous insects. However, for leafhoppers and planthoppers, host recognition is mainly thought to involve a phototactic response, but it is not clear if a host plant could be selected based on the volatile cues it emits. In this study we evaluated olfactory responses in dual choice tests of two Hemiptera species, Dalbulus maidis (De Long) (Cicadellidae) and Peregrinus maidis (Ashmead) (Delphacidae), vectors of maize-stunting diseases, to three maize (Zea mays L.) germplasms, a temperate and a tropical hybrid and a landrace. VOCs emitted by the germplasms were collected and identified using gas chromatography-mass spectrometry. The temperate hybrid released significantly more VOCs than the tropical hybrid and the landrace, and its volatile profile was dominated by (±)-linalool. D. maidis preferred odours emitted from the temperate hybrid, whereas P. maidis preferred odours from the tropical hybrid and the landrace over the temperate one. In order to test if linalool plays a role in the behavioural responses, we assayed this compound in combination with the tropical hybrid, to provide other contextual olfactory cues. D. maidis was attracted to the tropical hybrid plus a 0.0001% linalool solution, indicating that this compound could be part of a blend of attractants. Whereas addition of linalool resulted in a slight, though not significant, reduction in host VOC attractiveness for P. maidis. Both hopper species responded to olfactory cues in the absence of supplementary visual cues.

The early development of antenna and antennal sensilla in the noctuid moth, Agrotis segetum (Insecta: Lepidoptera)

1990 ◽  
Vol 48 (3) ◽  
pp. 502-503
Author(s):  
Eric Hallberg ◽  
Lina Hansén
Keyword(s):  
Cell Death ◽  
Stem Cell ◽  
Early Development ◽  
Larval Stage ◽  
Pupal Stage ◽  
Agrotis Segetum ◽  
Antennal Sensilla ◽  
Noctuid Moth ◽  
Standard Procedures

The antennal rudiments in lepidopterous insects are present as disks during the larval stage. The tubular double-walled antennal disk is present beneath the larval antenna, and its inner layer gives rise to the adult antenna during the pupal stage. The sensilla develop from a cluster of cells that are derived from one stem cell, which gives rise to both sensory and enveloping cells. During the morphogenesis of the sensillum these cells undergo major transformations, including cell death. In the moth Agrotis segetum the pupal stage lasts about 14 days (temperature, 25°C). The antennae, clearly seen from the exterior, were dissected and fixed according to standard procedures (3 % glutaraldehyde in 0.15 M cacaodylate buffer, followed by 1 % osmiumtetroxide in the same buffer). Pupae from day 1 to day 8, of both sexes were studied.

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