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Jacques Brodeur - One of the best experts on this subject based on the ideXlab platform.
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Preference and performance of the hyperparasitoid Syrphophagus aphidivorus (Hymenoptera: Encyrtidae): fitness consequences of selecting hosts in live aphids or aphid mummies
Ecological Entomology, 2004Co-Authors: R. Buitenhuis, Guy Boivin, Louise E. M. Vet, Jacques BrodeurAbstract:1. Theoretical models predict that ovipositional decisions of parasitoid females should lead to the selection of the most profitable host for parasitoid development. Most parasitoid species have evolved specific adaptations to exploit a single host stage. However, females of the aphid hyperparasitoid Syrphophagous aphidivorus (Mayr) (Hymenoptera: Encyrtidae) display a unique and atypical oviposition behaviour by attacking either primary parasitoid larvae in live aphids, or parasitoid pupae in dead, mummified aphids. 2. In the laboratory, the correlation between host suitability and host preference of S. aphidivorus on the host Aphidius Nigripes Ashmead parasitising the aphid Macrosiphum euphorbiae (Thomas) was investigated. 3. The relative suitability of the two host stages was determined by measuring hyperparasitoid fitness parameters (survival, development time, fecundity, sex ratio, and adult size of progeny), and calculating the intrinsic rate of population increase (rm). Host preference by S. aphidivorus females and the influence of aphid defence behaviour on host selection was also examined. 4. Hyperparasitoid offspring performance was highest when developing from hosts in aphid mummies and females consistently preferred this host to hosts in parasitised aphids. Although aphid defensive behaviour may influence host selection, it was not a determining factor. Ecological and evolutionary processes that might have led to dual oviposition behaviour in S. aphidivorus are discussed. [KEYWORDS: Host suitability ; offspring fitness ; oviposition ; preference ; parasitoid life history]
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Pheromone-mediated mating in the aphid parasitoid,Aphidius Nigripes (hymenoptera: Aphididae)
Journal of Chemical Ecology, 1995Co-Authors: Jeremy N. Mcneil, Jacques BrodeurAbstract:Mating in the aphid parasitoid, Aphidius Nigripes , is mediated by a female sex pheromone that stimulates both upwind flight and courtship behavior by males. There is no evidence of any overt behavior associated with the release of the pheromone, but bioassay results, using female extracts, suggest that the pheromone is produced in the abdomen, although it may be actively released from the entire body surface. Age does not appear to have a major influence on either pheromone production by the female or on male responsiveness. However, field data suggest the presence of a strong diel periodicity in the emission of and/or receptivity to the pheromone. Laboratory bioassay results indicated diel changes in the male response but more refined techniques are needed to determine if such periodicity exists in pheromone production by females. Following mating, female pheromone production is significantly reduced. The potential use of the parasitoid sex pheromone in integrated management of aphids is discussed.
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Seasonal ecology of Aphidius Nigripes (Hymenoptera: Aphidiidae), a parasitoid of Macrosiphum euphorbiae (Homoptera: Aphididae).
Environmental Entomology, 1994Co-Authors: Jacques Brodeur, Jeremy N. McneilAbstract:Aphidius Nigripes Ashmead is the most common parasitoid attacking the potato aphid Macrosiphum euphorbiae (Thomas) in eastern North America. In field and insectary experiments, >87% of A. Nigripes prepupae successfully overwintered. Spring emergence occurred from mid-April to mid-May, the period during which diapausing M. euphorbiae eggs are hatching on primary hosts. Data obtained from sticky traps indicate that both aphid and parasitoid enter the potato agroecosystem in early June, suggesting that one or several generations occur on primary host plants in the spring. The number of males captured in sticky traps containing virgin females indicated that the parasitoid is present in high numbers throughout the potato growing season. Diapause in A. Nigripes was observed from mid-August, when aphids had migrated back to their primary host plants. Our results do not support the hypotheses that inability of the parasitoid to overwinter or host-parasitoid asyncrony explain why A. Nigripes does not appear to have any major regulating effect on M. euphorbiae in the potato agroecosystem.
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Life history of the aphid hyperparasitoid Asaphes vulgaris Walker (Pteromalidae): possible consequences on the efficacy of the primary parasitoid Aphidius Nigripes Ashmead (Aphidiidae)
The Canadian Entomologist, 1994Co-Authors: Jacques Brodeur, Jeremy N. McneilAbstract:AbstractAspects of the life history of the aphid hyperparasitoid Asaphes vulgaris Walker, when reared on Aphidius Nigripes Ashmead, were investigated under laboratory conditions. Longevity was significantly related to temperature and to the sex of adults. Female life span was about 4 months at 15 °C compared with 46 days at 25 °C; under the same conditions male longevity was 66 and 19 days, respectively. Females started to oviposit in aphid mummies upon eclosion and lifetime fecundity was high, reaching 1433 offspring. The sex ratio (proportion of males) was low early in reproductive life but rose sharply after several weeks. The implications of these results on the efficacy of A. Nigripes in the potato agrosystem are discussed. It is suggested that high hyperparasitoid fecundity and longevity might play a role in reducing the impact of the primary parasitoid.
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Host behaviour modification by the endoparasitoid Aphidius Nigripes: a strategy to reduce hyperparasitism
Ecological Entomology, 1992Co-Authors: Jacques Brodeur, Jeremy N. McneilAbstract:. 1. One possible component of successful parasitism by insect parasitoids is the reduction of predation and hyperparasitism through the modification of host behaviour. 2. Just prior to death, potato aphids, Macrosiphum euphorbiae (Thomas), containing diapausing larvae of the parasitoid Aphidius Nigripes Ashmead have been shown to leave the host plant to mummify in concealed sites, while those parasitized by non-diapausing individuals generally leave the aphid colony to mummify on the upper leaf surfaces. 3. The present study examines the within plant distribution of aphids and mummies containing non-diapausing A.Nigripes, and compares parasitoid survival among microhabitats under field conditions. 4. On potato, Solunum tuberosum L., a significant proportion of aphids were found on lower leaf surfaces, whereas mummies were usually on the upper surfaces, particularly in the apical stratum of the plant canopy. 5. In both field surveys and experimental manipulations, parasitoid survival was higher on the upper surface of apical leaves than in other microhabitats, due to lower levels of hyperparasitism and, to a lesser extent, lower predation. This suggests that the pressure exerted by natural enemies has influenced the evolution of host behaviour modification.
Hamid Yarmand - One of the best experts on this subject based on the ideXlab platform.
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development of the entomopathogenic hyphomycete lecanicillium muscarium hyphomycetes moniliales on various hosts
European Journal of Endocrinology, 2007Co-Authors: Hassan Askary, Hamid YarmandAbstract:The present scanning electron microscopy study describes the development of Lecanicillium muscarium, strain DAOM 198499, on the surface of diverse hosts, including Sphaerotheca fuliginea, a fungal host, and Macrosiphum euphorbiae and Aphidius Nigripes, insect hosts. The hosts were sprayed with a conidial suspension of L. muscarium (107 conidia/ml). The specimens used in the SEM investigation were collected at particular periods after spraying and prepared for scanning using standard methods. Germination tubes developed twenty-four hours after applying L. muscarium conidia to each host. Hyphae were attached to the host by a thin mucilaginous matrix. Seventy-two hours after spraying, hyphae of S. fuliginea had collapsed and were encircled by the parasite, and primary sporulation of L. muscarium was observed. On the aphid host, colonization started with adherence of the conidia to the host cuticle, followed by conidial germination and growth of mycelium on the surface of the insect's integument. After 48 to 72 h, post colonization, the first sporulation was observed on the cuticle, particularly at articulations. The mode of parasitism of A. Nigripes by this fungus was similar to that of the aphid. Development of L. muscarium was observed on both mummified aphids (containing the pupae of parasitoids) and adult parasitoids.
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investigation on survival of Aphidius Nigripes ashmead hym aphidiidae reared on infected potato aphid by lecanicillium muscarium deut moniliaceae
Communications in agricultural and applied biological sciences, 2006Co-Authors: Hassan Askary, Ajam Hassani M, Hamid YarmandAbstract:: Survival of larval stages of endoparasitoid Aphidius Nigripes Ashmead was investigated on entomopathogen Lecanicillium muscarium (Zare and Gains) infected potato aphid Macrosiphum euphorbiae Thomas. Low and high concentrations of L. muscarium (10s and 10(7) blastospore/ml., respectively) were administered on parasitized aphid nymphs (by A. Nigripes) on 0, 2, 4 and 6 day intervals base. Distilled water with surfactant agent was used as control and 3 replicates were applied. Ten days following inoculation by the pathogen, aphid mortality; aphid progeny and emerged parasitoids were sampled to estimate the aphid survival, treated aphid net reproductive rate (Ro) and survival of parasitoid, respectively. Results demonstrated that parasitoid and pathogen collectively enhanced aphid mortality and lowered its net reproductive rate compared to any single use of the agents (P 0.05) between emerged parasitoid adults, both from fungus infected mummified aphids and control treatments.
Jeremy N. Mcneil - One of the best experts on this subject based on the ideXlab platform.
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Effects of Wind Speed and Atmospheric Pressure on Mate Searching Behavior in the Aphid Parasitoid Aphidius Nigripes (Hymenoptera: Aphidiidae)
Journal of Insect Behavior, 2000Co-Authors: David Marchand, Jeremy N. McneilAbstract:The effects of wind speed and atmospheric pressure on male mate searching behavior, modulated by a female sex pheromone, were investigated in the aphid parasitoid Aphidius Nigripes (Hymenoptera: Aphidiidae). Male A. nigripe generally did not reach females at wind speeds of 100 cm/sec, as the majority of individuals taking flight in the pheromone plume (81.8%) were unable to sustain upwind flight. At lower wind velocities, male responsiveness to females generally decreased with distance from the source. However, wind speeds approaching the upper threshold (100 cm/sec) tended to eliminate this distance effect. Therefore, there appears to be a trade-off between the need for higher wind speeds to detect the pheromone source from long distances, and a reduction in male flight capacity as wind velocity increases. Our results also indicate that chemical communication in A. Nigripes could be affected by variations in atmospheric pressure, as we observed a relationship between pressure fluctuations in the 24 hr prior to testing and male responsiveness to females. The importance of these abiotic factors on mate searching behavior is discussed within the context of the reproductive biology of A. Nigripes.
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Pheromone-mediated mating in the aphid parasitoid,Aphidius Nigripes (hymenoptera: Aphididae)
Journal of Chemical Ecology, 1995Co-Authors: Jeremy N. Mcneil, Jacques BrodeurAbstract:Mating in the aphid parasitoid, Aphidius Nigripes , is mediated by a female sex pheromone that stimulates both upwind flight and courtship behavior by males. There is no evidence of any overt behavior associated with the release of the pheromone, but bioassay results, using female extracts, suggest that the pheromone is produced in the abdomen, although it may be actively released from the entire body surface. Age does not appear to have a major influence on either pheromone production by the female or on male responsiveness. However, field data suggest the presence of a strong diel periodicity in the emission of and/or receptivity to the pheromone. Laboratory bioassay results indicated diel changes in the male response but more refined techniques are needed to determine if such periodicity exists in pheromone production by females. Following mating, female pheromone production is significantly reduced. The potential use of the parasitoid sex pheromone in integrated management of aphids is discussed.
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Seasonal ecology of Aphidius Nigripes (Hymenoptera: Aphidiidae), a parasitoid of Macrosiphum euphorbiae (Homoptera: Aphididae).
Environmental Entomology, 1994Co-Authors: Jacques Brodeur, Jeremy N. McneilAbstract:Aphidius Nigripes Ashmead is the most common parasitoid attacking the potato aphid Macrosiphum euphorbiae (Thomas) in eastern North America. In field and insectary experiments, >87% of A. Nigripes prepupae successfully overwintered. Spring emergence occurred from mid-April to mid-May, the period during which diapausing M. euphorbiae eggs are hatching on primary hosts. Data obtained from sticky traps indicate that both aphid and parasitoid enter the potato agroecosystem in early June, suggesting that one or several generations occur on primary host plants in the spring. The number of males captured in sticky traps containing virgin females indicated that the parasitoid is present in high numbers throughout the potato growing season. Diapause in A. Nigripes was observed from mid-August, when aphids had migrated back to their primary host plants. Our results do not support the hypotheses that inability of the parasitoid to overwinter or host-parasitoid asyncrony explain why A. Nigripes does not appear to have any major regulating effect on M. euphorbiae in the potato agroecosystem.
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Life history of the aphid hyperparasitoid Asaphes vulgaris Walker (Pteromalidae): possible consequences on the efficacy of the primary parasitoid Aphidius Nigripes Ashmead (Aphidiidae)
The Canadian Entomologist, 1994Co-Authors: Jacques Brodeur, Jeremy N. McneilAbstract:AbstractAspects of the life history of the aphid hyperparasitoid Asaphes vulgaris Walker, when reared on Aphidius Nigripes Ashmead, were investigated under laboratory conditions. Longevity was significantly related to temperature and to the sex of adults. Female life span was about 4 months at 15 °C compared with 46 days at 25 °C; under the same conditions male longevity was 66 and 19 days, respectively. Females started to oviposit in aphid mummies upon eclosion and lifetime fecundity was high, reaching 1433 offspring. The sex ratio (proportion of males) was low early in reproductive life but rose sharply after several weeks. The implications of these results on the efficacy of A. Nigripes in the potato agrosystem are discussed. It is suggested that high hyperparasitoid fecundity and longevity might play a role in reducing the impact of the primary parasitoid.
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Host behaviour modification by the endoparasitoid Aphidius Nigripes: a strategy to reduce hyperparasitism
Ecological Entomology, 1992Co-Authors: Jacques Brodeur, Jeremy N. McneilAbstract:. 1. One possible component of successful parasitism by insect parasitoids is the reduction of predation and hyperparasitism through the modification of host behaviour. 2. Just prior to death, potato aphids, Macrosiphum euphorbiae (Thomas), containing diapausing larvae of the parasitoid Aphidius Nigripes Ashmead have been shown to leave the host plant to mummify in concealed sites, while those parasitized by non-diapausing individuals generally leave the aphid colony to mummify on the upper leaf surfaces. 3. The present study examines the within plant distribution of aphids and mummies containing non-diapausing A.Nigripes, and compares parasitoid survival among microhabitats under field conditions. 4. On potato, Solunum tuberosum L., a significant proportion of aphids were found on lower leaf surfaces, whereas mummies were usually on the upper surfaces, particularly in the apical stratum of the plant canopy. 5. In both field surveys and experimental manipulations, parasitoid survival was higher on the upper surface of apical leaves than in other microhabitats, due to lower levels of hyperparasitism and, to a lesser extent, lower predation. This suggests that the pressure exerted by natural enemies has influenced the evolution of host behaviour modification.
R. Buitenhuis - One of the best experts on this subject based on the ideXlab platform.
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The Role of Honeydew in Host Searching of Aphid Hyperparasitoids
Journal of Chemical Ecology, 2004Co-Authors: R. Buitenhuis, J. N. Mcneil, G. Boivin, J. BrodeurAbstract:Foraging in many insect parasitoids is mediated by chemicals associated with hosts. For example, honeydew, the feces of feeding aphids, induces and/or prolongs searching behavior of aphid parasitoids. In the laboratory, we tested if aphid hyperparasitoids, which belong to a higher trophic level, also rely on aphid honeydew to locate their hosts. We used the potato aphid, Macrosiphum euphorbiae, the primary parasitoid, Aphidius Nigripes , and four hyperparasitoids, Asaphes suspensu s, Dendrocerus carpenteri, Alloxysta victrix , and Syrphophagus aphidivorus that possess different biological attributes and host ranges. We determined if foraging hyperparasitoid females could discriminate between (i) honeydew from a host and a non-aphid host (the potato aphid and the soft brown scale, Coccus hesperidum ), and (ii) honeydew from healthy aphids and those parasitized by A. Nigripes . Females of A. suspensus did not react to any of the honeydew treatments. While the presence of non-aphid honeydew did not modify the behavior of A. victrix , D. carpenteri , and S. aphidivorus females, they exhibited an increase in searching time and path length but not walking speed when in the presence of honeydew from aphids. However, there were no changes in host searching behaviors, such as antennation or ovipositor probing that have been reported for primary aphid parasitoids. There was no difference in the response of hyperparasitoid females to honeydew from healthy and parasitized aphids. These results indicate that hyperparasitoids may use aphid honeydew, a conspicuous cue from the second trophic level, as an infochemical to locate their hosts.
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Preference and performance of the hyperparasitoid Syrphophagus aphidivorus (Hymenoptera: Encyrtidae): fitness consequences of selecting hosts in live aphids or aphid mummies
Ecological Entomology, 2004Co-Authors: R. Buitenhuis, Guy Boivin, Louise E. M. Vet, Jacques BrodeurAbstract:1. Theoretical models predict that ovipositional decisions of parasitoid females should lead to the selection of the most profitable host for parasitoid development. Most parasitoid species have evolved specific adaptations to exploit a single host stage. However, females of the aphid hyperparasitoid Syrphophagous aphidivorus (Mayr) (Hymenoptera: Encyrtidae) display a unique and atypical oviposition behaviour by attacking either primary parasitoid larvae in live aphids, or parasitoid pupae in dead, mummified aphids. 2. In the laboratory, the correlation between host suitability and host preference of S. aphidivorus on the host Aphidius Nigripes Ashmead parasitising the aphid Macrosiphum euphorbiae (Thomas) was investigated. 3. The relative suitability of the two host stages was determined by measuring hyperparasitoid fitness parameters (survival, development time, fecundity, sex ratio, and adult size of progeny), and calculating the intrinsic rate of population increase (rm). Host preference by S. aphidivorus females and the influence of aphid defence behaviour on host selection was also examined. 4. Hyperparasitoid offspring performance was highest when developing from hosts in aphid mummies and females consistently preferred this host to hosts in parasitised aphids. Although aphid defensive behaviour may influence host selection, it was not a determining factor. Ecological and evolutionary processes that might have led to dual oviposition behaviour in S. aphidivorus are discussed. [KEYWORDS: Host suitability ; offspring fitness ; oviposition ; preference ; parasitoid life history]
Conrad Cloutier - One of the best experts on this subject based on the ideXlab platform.
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Proteomes of the aphid Macrosiphum euphorbiae in its resistance and susceptibility responses to differently compatible parasitoids.
Insect biochemistry and molecular biology, 2008Co-Authors: Thi Thuy An Nguyen, Dominique Michaud, Simon Boudreault, Conrad CloutierAbstract:Host insects are either susceptible or resistant to parasitoids, where resistant hosts express immunity factors and compatible parasitoids express virulence factors that may reveal the manipulation of susceptible hosts. Using proteomics we compared responses of the same host, the aphid Macrosiphum euphorbiae, challenged by a well-adapted parasitoid Aphidius Nigripes or by a less adapted relative, Aphidius ervi. The host was found to be equally acceptable to both parasitoids, but while A. Nigripes normally developed and killed hosts (high susceptibility), development of the incompatible A. ervi was arrested at the primary egg stage (high resistance). Two-dimensional gels at two stages of parasitism revealed divergence in patterns of protein regulation of the M. euphorbiae host, responding to A. ervi or A. Nigripes, with the greatest number of protein modulations in the host resistance response. In A. ervi-resistant hosts, proPO was strongly up-regulated, as were also three cuticle proteins, suggesting a PO basis and exoskeleton reinforcement as early and late responses of M. euphorbiae to the risk of parasitism. Resistance also correlated with up-regulation of antioxidative, energy-related, cytoskeleton and heat shock proteins. In A. Nigripes-susceptible hosts, various proteins implicated in host and bacterial symbiont metabolism were significantly altered, suggesting complex host nutritional modulation. Over-expression of energy-related proteins also increased when A. Nigripes established and developed. Aphid proteomes of compatible and incompatible Aphidius parasitism provide an integrative basis for consolidating our knowledge of host-parasitoid interactions.
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Recombinant and classically selected factors of potato plant resistance to the Colorado potato beetle, Leptinotarsa decemlineata, variously affect the potato aphid parasitoid Aphidius Nigripes
BioControl, 2001Co-Authors: A. Ashouri, Dominique Michaud, Conrad CloutierAbstract:Different forms of crop resistance developed against majorpotato pests such as the Colorado potato beetle (CPB), Leptinotarsadecemlineata , may be variously compatible with biological controlof secondary pests such as aphids. We compared the performance of theparasitoid Aphidius Nigripes developing in the aphid host Macrosiphum euphorbiae , on five potato lines, including atransgenic `Superior-BT' line expressing the CryIIIA toxin of Bacillus thuringiensis , which is specific to Coleoptera; andthe `NYL 235-4' line derived from Solanum berthaultii ,characterized by relatively unspecific resistance to herbivores based onmoderately-high density of glandular trichomes. The other lines testedwere a `Kennebec-OCI' transgenic line expressing the protease inhibitorrice cystatin I (OCI), a potential resistance factor against coleopteranpests; and the commercial cultivars `Superior' and `Kennebec' used ascontrols. Parasitoid immature survival and adult size were reducedcompared to controls when the wasps developed on aphids fed the`Superior-BT' potato. In contrast, parasitoid size and fecundityincreased above control when the wasps developed on aphids fed the`Kennebec-OCI' potato. Parasitoids reached the adult stage faster andwere more fecund on `NYL 235-4' than control lines. The results indicatethat the different forms of potato resistance currently developed mainlyagainst the CPB had various unexpected effects on aphid parasitoidfitness. These effects on the parasitoid were complex but were generallyinterpretable in terms of host aphid quality variation among potatolines used as food by the aphids during parasitoiddevelopment.