Adaptive Variation of Buchnera Endosymbiont Density in Aphid Host Acyrthosiphon pisum Controlled by Environmental Conditions

AbstractAphids have evolved bacteriocytes or symbiotic host cells that harbor the obligate mutualistic bacterium Buchnera aphidicola. Because of the large cell size (approximately 100 μm in diameter) of bacteriocytes and their pivotal role in nutritional symbiosis, researchers have considered that these cells are highly polyploid and assumed that bacteriocyte polyploidy may be essential for the symbiotic relationship between the aphid and the bacterium. However, little is known about the ploidy levels and dynamics of aphid bacteriocytes. Here, we quantitatively analyzed the ploidy levels in the bacteriocytes of the pea-aphid Acyrthosiphon pisum. Image-based fluorometry revealed the hyper polyploidy of the bacteriocytes ranging from 16- to 256-ploidy throughout the lifecycle. Bacteriocytes of adult parthenogenetic viviparous females were mainly 64-128C DNA levels, while those of sexual morphs (oviparous females and males) were consisted of 64C, and 32-64C cells, respectively. During post-embryonic development of viviparous females, the ploidy level of bacteriocytes increased substantially, from 16-32C at birth to 128-256C in actively reproducing adults. These results suggest that the ploidy levels are dynamically regulated among phenotypes and during development. Our comprehensive and quantitative data provides a foundation for future studies to understand the functional roles and biological significance of the polyploidy of insect bacteriocytes.

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A histological study of the invasive and developmental processes of the aphid pathogen Erynia neoaphidis (Zygomycotina: Entomophthorales) in the pea aphid Acyrthosiphon pisum

Canadian Journal of Botany ◽

10.1139/b90-281 ◽

1990 ◽

Vol 68 (10) ◽

pp. 2153-2163 ◽

Cited By ~ 27

Author(s):

T. M. Butt ◽

A. Beckett ◽

N. Wilding

Keyword(s):

Germ Tube ◽

Acyrthosiphon Pisum ◽

Histological Study ◽

The Body ◽

Plant Cuticle ◽

Erynia Neoaphidis ◽

Secondary Conidium ◽

Aphid Pathogen ◽

Aphid Host ◽

Primary Conidium

On landing on the surface of an aphid host, the primary conidium of Erynia neoaphidis produced either a secondary conidium, a germ tube, or an appressorium. Appressoria were usually globose or clavate and each produced a single penetration peg. A circular bore hole marked the penetration site. Once the fungus had breached the cuticle, it formed protoplasts that failed to elicit an obvious immune response and multiplied rapidly in the haemocoel and in tissues. When the body of the host was occluded (about 3 days after penetration at 20 °C), the protoplasts regenerated a wall and differentiated into rhizoids, which were confined to the midventral region of the dead insect, pseudocystidia, and conidiophores. The rhizoids terminated in a digitate holdfast that adhered firmly to the plant cuticle but did not penetrate it. Conidiophores appeared to break out through the host cuticle using a combination of enzymatic and mechanical means. Key words: Erynia neoaphidis, Entomophthorales, infection, development, aphid.

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Morphological variation ofAphidius erviHaliday (Hymenoptera: Braconidae) associated with different aphid hosts

PeerJ ◽

10.7717/peerj.3559 ◽

2017 ◽

Vol 5 ◽

pp. e3559 ◽

Cited By ~ 1

Author(s):

Cinthya M. Villegas ◽

Vladimir Žikić ◽

Saša S. Stanković ◽

Sebastián A. Ortiz-Martínez ◽

Ainara Peñalver-Cruz ◽

...

Keyword(s):

Biological Control ◽

Geometric Morphometrics ◽

Acyrthosiphon Pisum ◽

Biological Control Agent ◽

Feeding Habits ◽

Aphidius Ervi ◽

Wing Size ◽

Size And Shape ◽

Aphid Host ◽

Shape And Size

BackgroundParasitoids are frequently used in biological control due to the fact that they are considered host specific and highly efficient at attacking their hosts. As they spend a significant part of their life cycle within their hosts, feeding habits and life history of their host can promote specialization via host-race formation (sequential radiation). The specialized host races from different hosts can vary morphologically, behaviorally and genetically. However, these variations are sometimes inconspicuous and require more powerful tools in order to detect variation such as geometric morphometrics analysis.MethodsWe examinedAphidius ervi, an important introduced biological control agent in Chile associated with a great number of aphid species, which are exploiting different plant hosts and habitats. Several combinations (biotypes) of parasitoids with various aphid/host plant combinations were analyzed in order to obtain measures of forewing shape and size. To show the differences among defined biotypes, we chose 13 specific landmarks on each individual parasitoid wing. The analysis of allometric variation calculated in wing shape and size over centroid size (CS), revealed the allometric changes among biotypes collected from different hosts. To show all differences in shape of forewings, we made seven biotype pairs using an outline-based geometric morphometrics comparison.ResultsThe biotypeA. pis_pea(Acyrthosiphon pisumon pea) was the extreme wing size in this study compared to the other analyzed biotypes. Aphid hosts have a significant influence in the morphological differentiation of the parasitoid forewing, splitting biotypes in two groups. The first group consisted of biotypes connected withAcyrthosiphon pisumon legumes, while the second group is composed of biotypes connected with aphids attacking cereals, with the exception of theR. pad_wheat(Rhopalosiphum padion wheat) biotype. There was no significant effect of plant species on parasitoid wing size and shape.DiscussionAlthough previous studies have suggested that the genotype of parasitoids is of greater significance for the morphological variations of size and shape of wings, this study indicates that the aphid host on whichA. ervidevelops is the main factor to alter the structure of parasitoid forewings. Bigger aphid hosts implied longer and broader forewings ofA. ervi.

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Variation in intrinsic resistance of pea aphids to parasitoid wasps: A transcriptomic basis

PLoS ONE ◽

10.1371/journal.pone.0242159 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0242159

Author(s):

Ailsa H. C. McLean ◽

Benjamin J. Parker

Keyword(s):

Molecular Mechanisms ◽

Acyrthosiphon Pisum ◽

Early Stage ◽

Natural Populations ◽

Resistance Mechanisms ◽

Aphidius Ervi ◽

Parasitoid Wasps ◽

Intrinsic Resistance ◽

Braconid Wasp ◽

Aphid Host

Evolutionary interactions between parasitoid wasps and insect hosts have been well studied at the organismal level, but little is known about the molecular mechanisms that insects use to resist wasp parasitism. Here we study the interaction between a braconid wasp (Aphidius ervi) and its pea aphid host (Acyrthosiphon pisum). We first identify variation in resistance to wasp parasitism that can be attributed to aphid genotype. We then use transcriptome sequencing to identify genes in the aphid genome that are differentially expressed at an early stage of parasitism, and we compare these patterns in highly resistant and susceptible aphid host lines. We find that resistant genotypes are upregulating genes involved in carbohydrate metabolism and several key innate immune system genes in response to parasitism, but that this response seems to be weaker in susceptible aphid genotypes. Together, our results provide a first look into the complex molecular mechanisms that underlie aphid resistance to wasp parasitism and contribute to a broader understanding of how resistance mechanisms evolve in natural populations.

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Horizontal Transfer of Bacterial Symbionts: Heritability and Fitness Effects in a Novel Aphid Host

Applied and Environmental Microbiology ◽

10.1128/aem.71.12.7987-7994.2005 ◽

2005 ◽

Vol 71 (12) ◽

pp. 7987-7994 ◽

Cited By ~ 94

Author(s):

Jacob A. Russell ◽

Nancy A. Moran

Keyword(s):

Horizontal Transfer ◽

Acyrthosiphon Pisum ◽

Horizontal Transmission ◽

Transmission Efficiency ◽

Maternal Transmission ◽

Fitness Effects ◽

Mediated Effects ◽

Novel Host ◽

Microbial Symbionts ◽

Aphid Host

ABSTRACT Members of several bacterial lineages are known only as symbionts of insects and move among hosts through maternal transmission. Such vertical transfer promotes strong fidelity within these associations, favoring the evolution of microbially mediated effects that improve host fitness. However, phylogenetic evidence indicates occasional horizontal transfer among different insect species, suggesting that some microbial symbionts retain a generalized ability to infect multiple hosts. Here we examine the abilities of three vertically transmitted bacteria from the Gammaproteobacteria to infect and spread within a novel host species, the pea aphid, Acyrthosiphon pisum. Using microinjection, we transferred symbionts from three species of natural aphid hosts into a common host background, comparing transmission efficiencies between novel symbionts and those naturally infecting A. pisum. We also examined the fitness effects of two novel symbionts to determine whether they should persist under natural selection acting at the host level. Our results reveal that these heritable bacteria vary in their capacities to utilize A. pisum as a host. One of three novel symbionts failed to undergo efficient maternal transmission in A. pisum, and one of the two efficiently transmitted bacteria depressed aphid growth rates. Although these findings reveal that negative fitness effects and low transmission efficiency can prevent the establishment of a new infection following horizontal transmission, they also indicate that some symbionts can overcome these obstacles, accounting for their widespread distributions across aphids and related insects.

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Effects of Endosymbiont Disruption on the Nutritional Dynamics of the Pea Aphid Acyrthosiphon pisum

Insects ◽

10.3390/insects9040161 ◽

2018 ◽

Vol 9 (4) ◽

pp. 161 ◽

Cited By ~ 2

Author(s):

Ning Lv ◽

Lei Wang ◽

Wen Sang ◽

Chang-Zhong Liu ◽

Bao-Li Qiu

Keyword(s):

Energy Metabolism ◽

Host Plants ◽

Acyrthosiphon Pisum ◽

Soluble Sugars ◽

Pea Aphid ◽

Buchnera Aphidicola ◽

Phloem Sap ◽

Nutritional Factors ◽

Pea Aphids ◽

Aphid Host

Pea aphid (Acyrthosiphon pisum) is a worldwide pest that feeds exclusively on the phloem sap of numerous host plants. It harbours a well-known primary endosymbiont Buchnera aphidicola that helps to overcome the nutritional deficiency of a plant-based diet. However, how the Buchnera contributes to the nutritional and energy metabolism of its aphid host is unclear to date. In the current study, the function of Buchnera in relation to nutritional synthesis of pea aphid was investigated by disrupting the primary endosymbiont with an antibiotic rifampicin. Our findings revealed that the disruption of Buchnera led to infertility and higher loss in body mass of aphid hosts. Body length and width were also decreased significantly compared to healthy aphids. The detection of nutrition indicated that the quantity of proteins, soluble sugars, and glycogen in aposymbiotic pea aphids increased slowly with the growth of the aphid host. In comparison, the quantities of all the nutritional factors were significantly lower than those of symbiotic pea aphids, while the quantity of total lipid and neutral fat in aposymbiotic pea aphids were distinctly higher than those of symbiotic ones. Thus, we concluded that the significant reduction of the total amount of proteins, soluble sugars, and glycogen and the significant increase of neutral fats in aposymbiotic pea aphids were due to the disruption of Buchnera, which confirmed that the function of Buchnera is irreplaceable in the pea aphid.

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Parasitism and mating of Diaeretiella rapae (Hymenoptera Aphidiidae) in an uncontrolled environment

New Zealand Plant Protection ◽

10.30843/nzpp.2010.63.6599 ◽

2010 ◽

Vol 63 ◽

pp. 283-283

Author(s):

R. Kant ◽

M.A. Minor ◽

S.A. Trewick ◽

W.R.M. Sandanayaka

Keyword(s):

Sex Ratio ◽

Environmental Conditions ◽

Early Spring ◽

Late Spring ◽

Diaeretiella Rapae ◽

Parasitism Rate ◽

The Mean ◽

Significant Change ◽

Aphid Host

Parasitism and mating activities of Diaeretiella rapae were studied in a shadehouse under ambient environmental conditions during September (early spring) and November (late spring) Before collecting the data the parasitoid and its aphid host colonies were left to develop undisturbed on cabbage seedlings for 3 months in about 25 m2 area The plants were highly infested with aphids (average 27225 aphids/plant) and parasitism by D rapae varied between 25 and 36 during the study period There was no significant change in parasitism rate during the 10week study period (P069) Adult parasitoids emerged from aphid mummies at a rate of more than 90 with a higher number of females than males The mean female/male parasitoid sex ratio was greater in the second 5week (late spring) than the early 5week period (early spring) (P

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Parasitoid wasps influence where aphids die via an interspecific indirect genetic effect

Biology Letters ◽

10.1098/rsbl.2012.1151 ◽

2013 ◽

Vol 9 (3) ◽

pp. 20121151 ◽

Cited By ~ 8

Author(s):

Mouhammad Shadi Khudr ◽

Johan A. Oldekop ◽

David M. Shuker ◽

Richard F. Preziosi

Keyword(s):

Genetic Variation ◽

Acyrthosiphon Pisum ◽

Genetic Effect ◽

Parasitoid Wasp ◽

Aphidius Ervi ◽

Interacting Species ◽

Indirect Genetic Effect ◽

Host Parasite ◽

Aphid Host ◽

Behavioural Manipulation

Host–parasite interactions are a key paradigm for understanding the process of coevolution. Central to coevolution is how genetic variation in interacting species allows parasites to evolve manipulative strategies. However, genetic variation in the parasite may also be associated with host phenotype changes, thereby changing the selection on both species. For instance, parasites often induce changes in the behaviour of their host to maximize their own fitness, yet the quantitative genetic basis for behavioural manipulation has not been fully demonstrated. Here, we show that the genotype of the parasitoid wasp Aphidius ervi has a significant effect on where its aphid host Acyrthosiphon pisum moves to die following parasitism, including the likelihood that the aphid abandons the plant. These results provide a clear example of an interspecific indirect genetic effect whereby the genetics of one species influences the expression of a specific behavioural trait in another.

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Biotypes of Pea Aphid Acyrthosiphon pisum (Harris) in Relation to Alfalfa Clones

The Canadian Entomologist ◽

10.4039/ent97754-7 ◽

1965 ◽

Vol 97 (7) ◽

pp. 754-760 ◽

Cited By ~ 18

Author(s):

J. J. Cartier ◽

A. Isaak ◽

R. H. Painter ◽

E. L. Sorensen

Keyword(s):

Medicago Sativa ◽

Environmental Conditions ◽

Acyrthosiphon Pisum ◽

Pea Aphid ◽

Pea Aphids

AbstractTen alfalfa clones, Medicago sativa L., were tested at 60°, 70° and 80° F. in Kansas and Quebec for resistance to pea aphid biotypes, Acyrthosiphon pisum (Harris), originating in the respective areas.The resistance of the clones at the three temperatures varied differentially at the two locations. One clone was resistant at all temperatures to aphids of both locations. Results indicated that biotype C61-86 of the pea aphid at St. Jean, Quebec, is biologically different from the population of the same species in Kansas. Results also suggest the possibility of finding or combining clones so that varieties of alfalfa resistant to pea aphids over broad geographic areas and environmental conditions can be secured.

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