CONSPECIFIC SUPERPARASITISM IN TWO PARASITOID WASPS, APHIDIUS ERVI HALIDAY AND APHELINUS ASYCHIS WALKER: REPRODUCTIVE STRATEGIES INFLUENCE HOST DISCRIMINATION

1991 ◽  
Vol 123 (6) ◽  
pp. 1229-1237 ◽  
Author(s):  
B. Bai
Keyword(s):  
Reproductive Strategies ◽  
Acyrthosiphon Pisum ◽  
Aphidius Ervi ◽  
Parasitoid Wasps ◽  
Host Discrimination ◽  
Larval Competition ◽  
Parasitoid Species ◽  
Aphid Parasitoid ◽  
Aphelinus Asychis ◽  
Physiological Suppression

AbstractConspecific host discrimination and larval competition in two aphid parasitoid species were studied in the laboratory using the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), as a host. Aphidius ervi Haliday (Hymenoptera: Aphidiidae) used internal host cues to discriminate between unparasitized and conspecific parasitized hosts. When only parasitized hosts were available, females oviposited into recently parasitized ones where their progeny had a good chance to survive, but rejected those parasitized ≥24 h earlier where their offspring normally died. Competitions occurred only after both eggs had hatched. Larvae eliminated supernumeraries by means of physical combat and physiological suppression. In Aphelinus asychis Walker (Hymenoptera: Aphelinidae), factors, or changes in host internal condition, associated with hatching of the first egg resulted in suppression of conspecific competitors which could be in either larval or egg stage. The older larvae always won competitions through physiological means. A wasp’s oviposition decision is shown to be influenced by the probability of its progeny’s survival. Species that have different reproductive strategies may respond differently to identical host conditions.

HOST DISCRIMINATION BY THE APHID PARASITOID APHELINUS ASYCHIS (HYMENOPTERA: APHELINIDAE): WHEN SUPERPARASITISM IS NOT ADAPTIVE

1990 ◽  
Vol 122 (2) ◽  
pp. 363-372 ◽  
Author(s):  
B. Bai ◽  
M. Mackauer
Keyword(s):  
Egg Production ◽  
Acyrthosiphon Pisum ◽  
Host Acceptance ◽  
Parasitoid Species ◽  
Aphid Parasitoid ◽  
Egg Deposition ◽  
Aphelinus Asychis ◽  
Solitary Parasitoid ◽  
Long Time ◽  
Host Rejection

AbstractFemales of the solitary parasitoid Aphelinus asychis Walker discriminated between unparasitized and parasitized second-instar nymphs of the pea aphid, Acyrthosiphon pisum (Harris). Wasps normally avoided superparasitism, except when they were confined with few hosts for a long time. Parasitoid females did not need previous experience with unparasitized aphids (learning) in order to discriminate. They probed with the ovipositor any aphids encountered, a behaviour suggesting that host acceptance and rejection were determined by internal cues. Prolonged ovipositor insertion (>80 s) was correlated with host acceptance and egg deposition, but short insertion times (≤80 s) generally indicated host rejection. Females tended to reject both self- and conspecific-parasitized aphids when provided with two of each kind. We consider hypotheses mat conspecific superparasitism may be adaptive and give examples to show exceptions. We propose that, in egg-limited parasitoid species such as A. asychis, a reproductive strategy based on the regulation of egg production and on oosorption can explain the equal avoidance of self and conspecific superparasitism.

Electrophoretic study of five aphid parasitoid species of the genus Aphidius (Hymenoptera: Braconidae), including evidence for reproductively isolated sympatric populations and a cryptic species

1998 ◽  
Vol 88 (1) ◽  
pp. 3-13 ◽  
Author(s):  
P. Atanassova ◽  
C.P. Brookes ◽  
H.D. Loxdale ◽  
W. Powell
Keyword(s):  
Cryptic Species ◽  
Acyrthosiphon Pisum ◽  
Genetic Relationships ◽  
Pea Aphid ◽  
Parasitoid Species ◽  
Sympatric Populations ◽  
Electrophoretic Study ◽  
Aphid Parasitoid ◽  
Parasitoid Population ◽  
The Uk

AbstractFour polymorphic enzymes (PEP, PGI, PGM and IDH) were separated from adult individuals of five aphid parasitoid species of the genus Aphidius Nees (A. ervi Haliday, A. microlophii Pennacchio & Tremblay, A. eadyi Starý, Gonzalez & Hall, A. picipes Nees and A. urticae Haliday) using horizontal cellulose acetate plate electrophoresis. These markers were used to investigate the genetic relationships, including reproductive isolation and host adaptation/specificity, in laboratory and field populations. Samples were collected from the pea aphid, Acyrthosiphon pisum (Harris) and/or the nettle aphid, Microlophium carnosum (Buckton) in the UK and Bulgaria between 1991 and 1994. Whilst all loci discriminated between some species, PGM discriminated all five species, one species (A. eadyi) bearing two unique alleles (PGMa and PGMc). Aphidius microlophii (from nettle aphid) and A. ervi (from pea aphid), which are difficult to separate morphologically, possessed unique PGM alleles – PGMb and PGMe, respectively. Both parasitoids occur sympatrically, and whilst hybrids heterozygous for PGM were produced in the laboratory (PGMb,e), such genotypes were not observed in the field populations sampled. Hence, the species appear to be reproductively isolated. Most parasitoid populations studied showed mean heterozygote deficiencies per locus (homozygote excess) compared with Hardy-Weinberg expectations. In particular, A. eadyi bearing PGMa alleles were always homozygous whilst additionally, many were homozygous for another allele, PGIb. This is evidence for the existence of one or more morphologically-indistinguishable ‘cryptic’ species occurring sympatrically within European field populations. A dendrogram of relatedness was produced following calculation of Nei's genetic identity coefficient, I from the parasitoid population allele frequency data. All species showed very high similarity between populations at the intraspecific level (>0.9), but fewer interspecific similarities (0.23–0.63). These values compare well with previously published values for Aphidius populations and for other insects.

scholarly journals Aphids Facing Their Parasitoids: A First Look at How Chemical Signals May Make Higher Densities of the Pea Aphid Acyrthosiphon pisum Less Attractive to the Parasitoid Aphidius ervi

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 878
Author(s):  
Mohannad Ismail ◽  
Penelope Zanolli ◽  
Frédéric Muratori ◽  
Thierry Hance
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Aphidius Ervi ◽  
Aphid Parasitoid ◽  
Aphid Infestation ◽  
Induced Volatiles ◽  
Aphid Density ◽  
Infestation Density ◽  
Series Of Experiments ◽  
The Impact

Herbivore-induced plant volatiles constitute the first indicators of insect host presence, and these can affect the foraging behavior of their natural enemies. The density of insect hosts may affect the nature and concentration of these plant-induced volatiles. We tested the impact of infestation density (low, intermediate, and high) of the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae), feeding on the broad bean Vicia faba, on the attractiveness of the parasitoid Aphidius ervi (Hymenoptera: Braconidae), using a Y-tube olfactometer (infested vs. non-infested plants). The emitted volatile compounds from both infested and non-infested plants were collected and identified. In addition, two series of experiments were carried out to test the impact of the presence of a conspecific female parasitoid within the aphid/plant complex on the attractiveness to other females. Parasitoids were significantly more attracted to the plants with low and intermediate aphid infestation levels. The volatile blend composition of the infested plants changed in relation to aphid density and may explain the low attraction of parasitoids toward high aphid density. The presence of conspecific females on the aphid patch had no apparent impact on the behavioral choices of other parasitoid females. Our study adds a new aspect to understanding plant–aphid–parasitoid interactions, including the possibility that aphids may manipulate chemical cues of host plants affecting the orientation of parasitoids.

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

PLoS ONE ◽  
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.

scholarly journals Influence of “protective” symbionts throughout the different steps of an aphid–parasitoid interaction

2020 ◽  
Author(s):  
Corentin Sochard ◽  
Laura Bellec ◽  
Jean-Christophe Simon ◽  
Yannick Outreman
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Acyrthosiphon Pisum ◽  
Evolutionary Dynamics ◽  
Aphidius Ervi ◽  
Parasitic Wasps ◽  
Aphid Parasitoid ◽  
Trade Offs ◽  
Defensive Behaviors ◽  
Parasitoid Development

Abstract Microbial associates are widespread in insects, some conferring a protection to their hosts against natural enemies like parasitoids. These protective symbionts may affect the infection success of the parasitoid by modifying behavioral defenses of their hosts, the development success of the parasitoid by conferring a resistance against it or by altering life-history traits of the emerging parasitoids. Here, we assessed the effects of different protective bacterial symbionts on the entire sequence of the host-parasitoid interaction (i.e., from parasitoid attack to offspring emergence) between the pea aphid, Acyrthosiphon pisum, and its main parasitoid, Aphidius ervi and their impacts on the life-history traits of the emerging parasitoids. To test whether symbiont-mediated phenotypes were general or specific to particular aphid–symbiont associations, we considered several aphid lineages, each harboring a different strain of either Hamiltonella defensa or Regiella insecticola, two protective symbionts commonly found in aphids. We found that symbiont species and strains had a weak effect on the ability of aphids to defend themselves against the parasitic wasps during the attack and a strong effect on aphid resistance against parasitoid development. While parasitism resistance was mainly determined by symbionts, their effects on host defensive behaviors varied largely from one aphid–symbiont association to another. Also, the symbiotic status of the aphid individuals had no impact on the attack rate of the parasitic wasps, the parasitoid emergence rate from parasitized aphids nor the life-history traits of the emerging parasitoids. Overall, no correlations between symbiont effects on the different stages of the host–parasitoid interaction was observed, suggesting no trade-offs or positive associations between symbiont-mediated phenotypes. Our study highlights the need to consider various sequences of the host-parasitoid interaction to better assess the outcomes of protective symbioses and understand the ecological and evolutionary dynamics of insect–symbiont associations.

scholarly journals Performance of the parasitoid species Aphelinus asychis Walker (Hymenoptera: Aphelinidae), Aphidius ervi (Haliday) (Hymenoptera: Braconidae) and Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae), using Myzus persicae (Sulzer) (Hemiptera: Aphididae) as host

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Surjeet Kumar ◽  
Shruti Kashyap ◽  
Saurbh Soni
Keyword(s):  
Myzus Persicae ◽  
Control Program ◽  
Diaeretiella Rapae ◽  
North India ◽  
Aphidius Ervi ◽  
Host Feeding ◽  
Host Age ◽  
Parasitoid Species ◽  
Developmental Duration ◽  
Aphelinus Asychis

Abstract Three parasitoid species viz. Aphelinus asychis Walker (Hymenoptera: Aphelinidae), Aphidius ervi (Haliday) (Hymenoptera: Braconidae) and Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae) parasitizing the aphid species Myzus persicae (Sulzer) (Hemiptera: Aphididae) in mid-hills of north India were studied. At different locations and times of the year, the parasitization by A. asychis, A. ervi, and D. rapae ranged from 7.53 to 37.58, 4.26 to 80.45, and 74.25 to 80.48%, respectively. All the 3 parasitoids successfully completed their development on different nymphal instars of the aphid host and the total developmental duration of A. asychis, A. ervi, and D. rapae ranged 10.4–14.6, 24.2–29.6, and 10.2–15.2 days, respectively. It was significantly longer on the 1st nymphal instar of the host. The longevity of the female parasitoids was significantly longer than their counterparts. Differences in host age significantly influenced the longevity of female parasitoids and it was more on 1 to 2-day-old nymphs than that on 4 to 5-day-old nymphs. Fecundity and ovipositional periods of the parasitoids on younger (1–2 days old) host age group were considerably prolonged than on the older ages of the aphid. Average total fecundity of A. asychis and D. rapae was significantly higher when parasitizing 1–2-day-old nymphs. In A. asychis, host feeding behavior was also observed by a total host feeding of 89.2 aphids (1–2 days old) and 43.4 aphids (4–5 days old) during its life span. It is concluded that A. asychis, A. ervi, and D. rapae can be mass reared using M. persicae as host and can be utilized successfully in augmentative biological control program.

scholarly journals Evidence for specificity in symbiont-conferred protection against parasitoids

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150977 ◽  
Author(s):  
Ailsa H. C. McLean ◽  
H. Charles J. Godfray
Keyword(s):  
Genetic Diversity ◽  
Host Plants ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Aphidius Ervi ◽  
Symbiotic Bacteria ◽  
Parasitoid Wasps ◽  
Bacterial Symbionts ◽  
Wasp Species ◽  
Hamiltonella Defensa

Many insects harbour facultative symbiotic bacteria, some of which have been shown to provide resistance against natural enemies. One of the best-known protective symbionts is Hamiltonella defensa , which in pea aphid ( Acyrthosiphon pisum ) confers resistance against attack by parasitoid wasps in the genus Aphidius (Braconidae). We asked (i) whether this symbiont also confers protection against a phylogenetically distant group of parasitoids (Aphelinidae) and (ii) whether there are consistent differences in the effects of bacteria found in pea aphid biotypes adapted to different host plants. We found that some H. defensa strains do provide protection against an aphelinid parasitoid Aphelinus abdominalis. Hamiltonella defensa from the Lotus biotype provided high resistance to A. abdominalis and moderate to low resistance to Aphidius ervi , while the reverse was seen from Medicago biotype isolates. Aphids from Ononis showed no evidence of symbiont-mediated protection against either wasp species and were relatively vulnerable to both. Our results may reflect the different selection pressures exerted by the parasitoid community on aphids feeding on different host plants, and could help explain the maintenance of genetic diversity in bacterial symbionts.

The fate of released parasitoids (Hymenoptera: Braconidae, Aphidiinae) for biological control of aphids in Chile

1993 ◽  
Vol 83 (4) ◽  
pp. 633-639 ◽  
Author(s):  
Petr Starý
Keyword(s):  
Biological Control ◽  
Host Range ◽  
Diuraphis Noxia ◽  
Aphidius Ervi ◽  
Parasitoid Species ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Aphid Parasitoid ◽  
Ecological Relationships ◽  
Ephedrus Cerasicola

AbstractResearch on aphid-parasitoid associations was carried out in Chile in 1979–80 and 1991–92 on the biological control of the cereal aphid pests Metopolophium dirhodum (Walker), Sitobion avenae (Fabricius), and Diuraphis noxia (Mordvilko). The introduced parasitoid species, Aphidius ervi Haliday, A. rhopalosiphi De Stefani Perez, A. smithi Sharma & Subba Rao, A. uzbekistanicus Luzhetski, Ephedrus cerasicola Starý, E. nacheri QuilisPerez, E. plagiator (Nees), Monoctonus nervosus (Haliday), Prnon gallicum Starý, P. volucre (Haliday) were all recovered in cereal and other ecosystems. Most of the parasitoids had adapted well and some of them had even extended their host range; ecological relationships were all found to extend beyond those of the target pests. The parasitoid complex, which had developed from the indigenous and introduced species, was found to be successful in preventive biocontrol and the endemic fauna of Chile was not affected.

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