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Francesco Pennacchio - One of the best experts on this subject based on the ideXlab platform.
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flight behaviour of the aphid parasitoid Aphidius ervi hymenoptera braconidae in response to plant and host volatiles
European Journal of Entomology, 2013Co-Authors: Emilio Guerrieri, Francesco Pennacchio, E TremblayAbstract:The flight behaviour of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) has been studied in a wind tunnel, in response to the following natural odour sources: broad bean plants infested with Acyrthosiphon pisum (Harris) (Homoptera: Aphididae) (PHC, plant-host complex), damaged broad bean plants from which the aphids were removed (HDP, host damaged plants), aphids (H, host) and uninfested broad bean plants (P, plant). The most attractive odour sources were PHC and HDP, which both stimulated a similar high number of oriented straight flights. In contrast, H and P were much less attractive and did not seem to be important in the long range attraction of the parasitoids.
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cornicle secretion of acyrthosiphon pisum homoptera aphididae as a contact kairomone for the parasitoid Aphidius ervi hymenoptera braconidae
European Journal of Entomology, 2013Co-Authors: Donatella Battaglia, Francesco Pennacchio, G Marincola, A TranfagliaAbstract:Females of the endophagous parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) respond positively to the cornicle secretion of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae). The parasitoid response has been assessed in a Petri dish choice test by presenting an aphid dummy consisting of a glass bead coated with cornicle secretion along with an untreated bead, which acted as a control. Naive females responded similarly to the treated glass beads and aphids, while experienced females responded less to the treated beads than to aphids. The kairomonal activity of the cornicle secretion decreased as the wax dried. The behavioural response registered seems to be innate and not induced by associative learning.
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functional analysis of a fatty acid binding protein produced by Aphidius ervi teratocytes
Journal of Insect Physiology, 2012Co-Authors: Silvia Caccia, Patrizia Falabella, Francesco Pennacchio, M Casartelli, Annalisa Grimaldi, Magda De Eguileor, B GiordanaAbstract:Abstract Aphidius ervi (Hymenoptera, Braconidae) is an endophagous parasitoid of various aphid species, including Acyrthosiphon pisum (Homoptera, Aphididae), the model host used in the present study. Parasitized hosts show a marked increase of their nutritional suitability for the developing parasitoid larvae. This alteration of the biochemical and metabolic profile is due to a castration process mediated by the combined action of the venom, injected at the oviposition, and of the teratocytes, cells deriving from the dissociation of the embryonic membrane. Teratocytes produce and release in the host haemocoel two parasitism-specific proteins, which are of crucial importance for the development of their sister larvae. One of the proteins is a fatty acid binding protein (Ae-FABP), which shows a high affinity for C14–C18 saturated fatty acids (FAs) and for oleic and arachidonic acids. To better define the possible nutritional role of this protein, we have studied its immunolocalization profile in vivo and the impact on FA uptake by the epidermal and midgut epithelia of A. ervi larvae. During the exponential growth of A. ervi larvae, Ae-FABP is distributed around discrete lipid particles, which are abundantly present in the haemocoel of parasitized host aphids and in the midgut lumen of parasitoid larvae. Moreover, a strong immunodetection signal is evident on the surface of the two larval epithelia involved in nutrient absorption: the parasitoid midgut epithelium and the external epidermal layer. These two epithelia can effectively absorb radiolabelled myristic acid, but the FA transport rates are not affected by the presence in the medium of Ae-FABP. The protein appears to act essentially as a vector in the host haemolymph, transferring FAs from the digestion sites of host lipids to the growing parasitoid larvae. These data indicate that the proteins produced by A. ervi teratocytes may play complementary roles in the nutritional exploitation of the host.
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Aphidius ervi teratocytes release an extracellular enolase
Insect Biochemistry and Molecular Biology, 2009Co-Authors: Patrizia Falabella, L Riviello, Maria Luisa De Stradis, Carmela Stigliano, Paola Varricchio, Annalisa Grimaldi, Magda De Eguileor, Franco Graziani, Silvia Gigliotti, Francesco PennacchioAbstract:Abstract We report the cloning of a gene and the characterization of the encoded protein, which is released by the teratocytes of the parasitoid Aphidius ervi in the haemocoel of the host aphid Acyrthosiphon pisum . The studied protein was identified by LC-MS/MS, and the gathered information used for isolating the full length cDNA. The corresponding gene was made of 3 exons and 2 introns, and was highly expressed in the adult wasps and in parasitized hosts. The translation product, which was named Ae -ENO, showed a very high level of sequence identity with insect enolases. In vivo immunodetection experiments evidenced Ae -ENO localization in round spots, present in the teratocytes and released in the host haemocoel. Moreover, strong immunoreactivity was detected on the surface of A. ervi larvae and of host embryos. Ae -ENO expressed in insect cells was not secreted in the medium, indicating the occurrence in the teratocytes of an unknown pathway for Ae -ENO release. The recombinant protein produced in bacteria under native conditions was a dimer, with evident enolase activity ( K m = 0.086 ± 0.017 mM). Enolase is a well known enzyme in cell metabolism, which, however, is associated with a multifunctional role in disease, when present in the extracellular environment, on the surface of prokaryotic and eukaryotic cells. In these cases, the enolase mediates the activation of enzymes involved in the invasion of tissues by pathogens and tumour cells, and in the evasion of host immune response. The possible role played by Ae -ENO in the host regulation process is discussed in the light of this information.
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functional bases of host acceptance behaviour in the aphid parasitoid Aphidius ervi
Physiological Entomology, 2007Co-Authors: Anna Larocca, Francesco Pennacchio, Paolo Fanti, Sara Ruschioni, Roberto Romani, Nunzio Isidoro, Vito Antonio Romano, Emilia Marsicovetere, Donatella BattagliaAbstract:The host acceptance behaviour in Aphidius ervi is investigated, assessing the role of both external and internal host-associated cues, offered to the experimental parasitoids with parafilm-made aphid dummies. The reaction to internal cues present in the host haemolymph is clearly evident, and its intensity is enhanced by external cues. Parasitoid females lay few eggs in aphid dummies filled with host haemolymph. A significant increase in the number of both oviposition reactions (host stinging) and egg laying is observed only when these dummies are coated with cornicle secretion. However, this enhancement is not observed when the aphid dummies contain distilled water. Thus, the host acceptance behaviour of A. ervi females appears to be controlled by the integration of both external and internal chemical cues. The physiological basis of this behavioural response is investigated with a detailed study on the anatomy and ultrastructure of A. ervi ovipositor. The detection of chemical cues present in the host haemolymph that act as kairomones is made possible by the presence of gustatory sensilla on the tip of the ovipositor. These sensilla consist of porous areas, reached by unbranched dendrites running inside both the lower valves (i.e. first valvulae) and the unpaired upper valve (i.e. second valvulae). The mechanosensory function during ovi- position appears to be provided mostly by the basiconic sensilla found on the tip of external valves (i.e. third valvulae). A tentative functional model accounting for the observed oviposition behaviour of A. ervi is proposed.
Emilio Guerrieri - One of the best experts on this subject based on the ideXlab platform.
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Unintended effects of a Phytophtora-resistant cisgenic potato clone on the potato aphid Macrosiphum euphorbiae and its parasitoid Aphidius ervi
Journal of Pest Science, 2018Co-Authors: P. Cascone, M. Radkova, S. Arpaia, S. Errico, L. A. P. Lotz, R. A. Magarelli, D. Djilianov, Emilio GuerrieriAbstract:Genetically modified (GM) plants may show unintended differences compared to the original varieties, due to the modification process. Such differences might in some cases affect non-target organisms linked to the crop into an agro-ecosystem. In this paper, we aimed to study interactions of two blight-resistant GM potato clones with the aphid species Macrosiphum euphorbiae Thomas, a non-target arthropod frequently feeding on potato plants and one of the major pests of that crop. One of the potato events used in our experiments caused an increased fertility of the aphids in the first generation, and consequently, a positive effect on the growth of the aphid population was estimated. When a second generation of the aphid was reared on potato leaves of the same GM event, differences in aphid fertility were no longer observed. Behavioural studies conducted in a wind tunnel using the aphid parasitoid Aphidius ervi Haliday indicated that neither of the two tested GM varieties had a significant effect on the attractiveness of potato plants towards the parasitoid . In planta tests proved to be sensitive protocols to detect unintended effects on a non-target arthropod; experimental results, however, indicate that these effects are not expected to be biologically relevant in this tritrophic system, if these GM events become available for commercial use in the future.
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flight behaviour of the aphid parasitoid Aphidius ervi hymenoptera braconidae in response to plant and host volatiles
European Journal of Entomology, 2013Co-Authors: Emilio Guerrieri, Francesco Pennacchio, E TremblayAbstract:The flight behaviour of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) has been studied in a wind tunnel, in response to the following natural odour sources: broad bean plants infested with Acyrthosiphon pisum (Harris) (Homoptera: Aphididae) (PHC, plant-host complex), damaged broad bean plants from which the aphids were removed (HDP, host damaged plants), aphids (H, host) and uninfested broad bean plants (P, plant). The most attractive odour sources were PHC and HDP, which both stimulated a similar high number of oriented straight flights. In contrast, H and P were much less attractive and did not seem to be important in the long range attraction of the parasitoids.
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Electrophysiological and behavioural responses of Aphidius ervi (Hymenoptera: Braconidae) to tomato plant volatiles
Chemoecology, 2009Co-Authors: Raffaele Sasso, John Anthony Pickett, Christine M. Woodcock, L. Iodice, Emilio GuerrieriAbstract:Flight responses of the aphid parasitoid Aphidius ervi to tomato volatiles have recently demonstrated that different plant stresses can lead to increases in attractiveness for this parasitoid. For example, infestation of tomato plants by the aphid Macrosiphum euphorbiae results in the overexpression of defensive genes, as well as the release of volatile compounds that attract aphid parasitoids. Here, we determine which of the induced compounds elicit a significant electrophysiological response from parasitoid antennae. Compounds shown to be detected at the antennal level were then tested at a range of doses in a wind tunnel assay. A significant electroantennogram response was demonstrated for three compounds, (8 S ,9 R )-( E )-caryophyllene, methyl salicylate, and ( Z )-3-hexen-1-ol, over four concentrations. These compounds proved to be significantly attractive in the wind tunnel at a rate not always proportionally dependent upon the dose. The practical implications of these findings are discussed in the framework of sustainable control for pest aphids in agriculture.
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host locating response by the aphid parasitoid Aphidius ervi to tomato plant volatiles
Journal of Plant Interactions, 2007Co-Authors: Raffaele Sasso, L. Iodice, Maria Cristina Digilio, Andrea Carretta, Luigi Ariati, Emilio GuerrieriAbstract:Abstract The blend of volatile compounds emitted by tomato plants (Solanum lycopersicum) infested with the potato aphid (Macrosiphum euphorbiae) has been studied comparatively with undamaged plants and aphids themselves. Aphid-infested plants were significantly more attractive towards Aphidius ervi than undamaged plants and aphids themselves. Oriented response towards host-damaged plant, from which aphids were removed just before running the bioassay, did not differ from that recorded for infested plants. Collection of the volatiles and analysis by gas chromatography revealed only quantitative differences between uninfested and aphid-infested plants. Nine compounds, α-pinene, (Z)-3-hexen-1-ol, α-phellandrene, limonene, (E)-β-ocimene, p-cymene, methyl salicylate, (E)-β-caryophyllene and an unknown compound, were emitted at higher levels from aphid-infested plants than from undamaged control plants, whilst no differences were noted for hexanal, 6-methyl-5-hepten-2-one, and humulene (=α-caryophyllene). Synth...
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Plant-to-Plant Communication Mediating In-Flight Orientation of Aphidius ervi
Journal of Chemical Ecology, 2002Co-Authors: Emilio Guerrieri, W. Powell, G. M. Poppy, Francesco PennacchioAbstract:Broad bean plants ( Vicia faba ) infested by the pea aphid, Acyrthosiphon pisum , play a key role in the in-flight orientation of the parasitoid Aphidius ervi , by producing host-induced synomones (HIS). These volatiles are herbivore-specific and are systemically released from insect-free parts of an infested plant, suggesting the existence of an elicitor circulating throughout the plant. This study was designed to investigate whether the plant metabolic changes, leading to HIS biosynthesis and emission, can in some way trigger similar responses in neighboring plants through aerial and/or root communication. Uninfested broad bean plants maintained in the same pot together with plants infested by A. pisum became more attractive towards A. ervi females when tested in a wind-tunnel bioassay. This change was not observed when root contact was prevented among plants that had their aerial parts in close proximity, suggesting that an exudate from the roots of the infested plant may cause the induction of the attractive volatiles in uninfested plants. Broad bean plants grown hydroponically also produce pea aphid induced signals that attract A. ervi . When an intact (uninfested) plant was placed in a hydroponic solution previously used to grow a pea aphid-infested plant, it became attractive to parasitoids, while an intact plant placed in a solution previously used to grow an intact plant did not undergo such a change. These results indicate that plant-to-plant signaling in this tritrophic system may occur at the rhizosphere level and is most likely mediated by a systemically translocated elicitor.
Hermann M Niemeyer - One of the best experts on this subject based on the ideXlab platform.
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male wing fanning by the aphid parasitoid Aphidius ervi hymenoptera braconidae produces a courtship song
Bulletin of Entomological Research, 2011Co-Authors: C A Villagra, Carlos F Pinto, M Penna, Hermann M NiemeyerAbstract:We, herein, report evidence that wing fanning by the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) constitutes a courtship song. Complete removal of the forewings or only the distal half of them reduced male copulation success in comparison to intact males. Males that achieved copulation within the observation period produced wing fanning at a higher rate than males that did not copulate. Playback of wing fanning sound altered the behaviour of virgin females, increasing the time they devoted to grooming, as compared with subjects that were exposedto silence or white noise. Our findings contribute to the understanding of the acoustic dimension of the sensory modalities employed by this aphid parasitoid in sexual signalling.
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olfactory conditioning in mate searching by the parasitoid Aphidius ervi hymenoptera braconidae
Bulletin of Entomological Research, 2008Co-Authors: Cristian A Villagra, Rodrigo A Vasquez, Hermann M NiemeyerAbstract:Despite the fact that insect learning capacity has been broadly demonstrated, the role that this process plays during mate searching has been scarcely explored. We studied whether the sexual behaviour of a male parasitic wasp can be conditioned to the odours from two alternative host plant complexes (HPCs) present during its first copulation. The experimental subjects were newly emerged males of the aphid parasitoid, Aphidius ervi, and two alternative HPCs (alfalfa or wheat). In the training protocol, copulation experience corresponded to an unconditioning stimulus and HPC odours to the conditioning stimuli. The initial (just after eclosion) and trained responses were assessed in a glass Y-olfactometer. The results showed that neither alfalfa HPC nor wheat HPC stimuli elicited sexualrelated behaviours in initial male responses. Conversely, both HPCs triggered strong attraction and wing fanning courtship behaviour in trained responses when the male was exposed to a female plus HPC during training. In males trained with females plus a given HPC but tested with the alternative HPC in the olfactometer, trained response showed a similar trend to the non-associative treatments. Hence, through learning, the olfactory stimulus context present during copulation could become a predictive cue for further mate searching. These results are discussed in terms of parasitic wasp ecology and host fidelity.
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increased xylem ingestion and decreased phloem ingestion in the aphid acyrthosiphon pisum hemiptera aphididae parasitised by Aphidius ervi hymenoptera braconidae
European Journal of Endocrinology, 2006Co-Authors: Claudio C Ramirez, Cristian A Villagra, Hermann M NiemeyerAbstract:The effects of parasitisation by Aphidius ervi on the feeding behaviour of the aphid Acyrthosiphon pisum were studied. There was progressive increase in the time devoted to xylem ingestion (G waveform) and concomitant decrease in time devoted to phloem ingestion (E2 waveform) in parasitized relative to unparasitized aphids, as the time from parasitisation increased. These changes are interpreted as a way aphids compensate for metabolic changes occurring during parasitisation.
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associative odour learning affects mating behaviour in Aphidius ervi males hymenoptera braconidae
European Journal of Endocrinology, 2005Co-Authors: Cristian A Villagra, Rodrigo A Vasquez, Hermann M NiemeyerAbstract:We used the aphid parasitoid Aphidius ervi reared in its host Acyrthosiphon pisum to examine if male sexual attractive responses can be conditioned to an odour (vanilla) that is not present in the natural environment. We used prior mating experience (exposure to females) as a non-conditioning stimulus and vanilla odour as a conditioning stimulus. The behavioural responses were tested in a glass Y-olfactometer just after eclosion (i.e., initial response) and after a training experience (i.e., trained response). During the 10-min training period individual males were allowed to copulate with a virgin female with or without vanilla odour pre- sent, or were exposed only to vanilla odour. Wing fanning was a recurrent behaviour which denoted increased sexual attraction to a volatile stimulus. Total time and time doing wing fanning in each olfactometer arm were determined. Vanilla odour, which initially did not elicit sexual-related behaviours, triggered strong sexual attractive responses when males were trained to females plus vanilla odour. Neither copulation only nor vanilla odour only treatments elicited such behaviours in trained males. The results are discussed in terms of parasitoid learning ability and its ecological consequences.
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acceptance and suitability of acyrthosiphon pisum and sitobion avenae as hosts of the aphid parasitoid Aphidius ervi hymenoptera braconidae
European Journal of Endocrinology, 2003Co-Authors: Pauline Dazabustamante, Eduardo Fuentescontreras, Hermann M NiemeyerAbstract:Aphidius ervi Haliday is a parasitoid of natural populations of both Acyrthosiphon pisum (Harris) on alfalfa and Sitobion avenae (Fabricius) on wheat in Chile. In this study the performance of the aphid parasitoid on both host species was evaluated. Regardless of origin, both females and males of A. ervi were significantly smaller when reared on S. avenae than on A. pisum. Males and females of A. ervi reared on S. avenae on wheat also took significantly longer to develop than when reared on A. pisum. There was no significant difference in the sex ratio of the parasitoid when reared on these two host aphids. Survival of parasitoids from the A. pisum - alfalfa system was significantly lower when reared on S. avenae relative to those reared on A. pisum, but no significant difference in survival on both hosts was detected in parasitoids from the S. avenae - wheat system. Behaviour of parasitoid females during oviposition, such as frequency of encounters, number of attacks and stabbings of host aphids, were significantly higher in the A. pisum - A. ervi interaction than in the S. avenae - A. ervi interaction, regardless of the origin of the parasitoid. Aphid defensive reactions such as kicking or production of cornicle secretion, were significantly higher in the A. pisum - A. ervi than the S. avenae - A. ervi interaction. The results are discussed in relation to the effect of host quality and host aphid body size on parasitoid development.
Thierry Hance - One of the best experts on this subject based on the ideXlab platform.
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Presence of less-preferred hosts of the aphid parasitoids Aphidius ervi and Praon volucre reduces parasitism efficiency
Phytoparasitica, 2018Co-Authors: Muhammad Mubashir Saeed, Abu Bakar Muhammad Raza, Muhammad Afzal, Anjum Aqueel, Muhammad Farooq, Thierry HanceAbstract:Parasitoids are characterized by a defined range of hosts, either more specialist or generalist. Under natural conditions, females may encounter different host species on the same plant or in the same location. In this case, their preference for one host could influence their choice. However, the presence of less suitable hosts may also affect their choice and, in some cases, may reduce their interest in a patch where both preferred and less preferred hosts are available. The aim of the present study was to test the consequences of the simultaneous presence of three cereal aphids ( Sitobion avenae Fabricius , Metopolophium dirhodum Walker , and Rhopalosiphum padi Linnaeus ) on the parasitism by two of their parasitoids, Aphidius ervi Haliday and Praon volucre Haliday. Firstly, in the no-choice experiment, A. ervi parasitized on S. avenae at a significantly higher rate as compared to M . dirhodum , whereas no parasitism on R. padi was observed. P. volucre parasitized the three species of cereal aphids with a significant preference for S. avenae . Interestingly, when two or three host species were offered simultaneously in the same quantity to pairs of parasitoids, the level of parasitism was less than that observed for one host species alone. This observation exhibits a distractive effect on non-host species, from the defense mechanism of a non-suitable host or from the perception of bad quality patches. These results raise the question of the practical application of inundative release of parasitoids for biocontrol when several hosts are available simultaneously.
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Fitness consequences of low temperature storage of Aphidius ervi
BioControl, 2014Co-Authors: Mohannad Ismail, Philippe Vernon, Joan Van Baaren, Valérie Briand, Jean-sébastien Pierre, Thierry HanceAbstract:In biological control programs, storage at low temperatures is used to produce large number of individuals before inundative releases. However, an exposure to low temperatures may affect the survival of exposed individuals and some life history traits such as the daily fecundity or the longevity of the survivors. This impact on life history traits is important because they will determine the growth potential of the population. To estimate the costs of different treatments of low temperature exposure, we analyzed the main instantaneous demographic parameters of the parental generation of Aphidius ervi Haliday (Hymenoptera: Braconidae: Aphidiinae) when exposed to three storage temperatures (7, 4 and 0 °C), combined with two storage durations (one and two weeks) and two thermal regimes (constant and fluctuating), which represents a total of 12 treatments and a control. The average cohort generation time ( Tc ) decreased significantly after exposure to low temperature, particularly in fluctuating treatments. This means that development continues during storage. Cumulative fecundity and the net reproductive rate ( R _ 0 ) decreased significantly for most of the storage treatments. This decrease was most pronounced in the constant temperature treatments. Females under fluctuating thermal regime produced a higher cumulative fecundity than those exposed to constant temperatures. Surprisingly, an exposure to 0 °C over one week did not affect emergence rate and fecundity whereas all other treatments did. Storage at low temperatures may affect the efficiency of inundative releases, with the exception of storage for one week at 0 °C. Moreover, cumulative fecundity and net reproductive rate ( R _ 0 ) represent a more immediate prediction of the increase of the population after low temperature exposure than the intrinsic rate of increase ( r _ m ), and reflect the qualities required in an inundative release context.
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fitness consequences of low temperature storage of Aphidius ervi
Biocontrol, 2014Co-Authors: Mohannad Ismail, Philippe Vernon, Joan Van Baaren, Valérie Briand, Jean-sébastien Pierre, Thierry HanceAbstract:In biological control programs, storage at low temperatures is used to produce large number of individuals before inundative releases. However, an exposure to low temperatures may affect the survival of exposed individuals and some life history traits such as the daily fecundity or the longevity of the survivors. This impact on life history traits is important because they will determine the growth potential of the population. To estimate the costs of different treatments of low temperature exposure, we analyzed the main instantaneous demographic parameters of the parental generation of Aphidius ervi Haliday (Hymenoptera: Braconidae: Aphidiinae) when exposed to three storage temperatures (7, 4 and 0 °C), combined with two storage durations (one and two weeks) and two thermal regimes (constant and fluctuating), which represents a total of 12 treatments and a control. The average cohort generation time (Tc) decreased significantly after exposure to low temperature, particularly in fluctuating treatments. This means that development continues during storage. Cumulative fecundity and the net reproductive rate (R 0 ) decreased significantly for most of the storage treatments. This decrease was most pronounced in the constant temperature treatments. Females under fluctuating thermal regime produced a higher cumulative fecundity than those exposed to constant temperatures. Surprisingly, an exposure to 0 °C over one week did not affect emergence rate and fecundity whereas all other treatments did. Storage at low temperatures may affect the efficiency of inundative releases, with the exception of storage for one week at 0 °C. Moreover, cumulative fecundity and net reproductive rate (R 0 ) represent a more immediate prediction of the increase of the population after low temperature exposure than the intrinsic rate of increase (r m ), and reflect the qualities required in an inundative release context. © 2013 International Organization for Biological Control (IOBC).
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encounters with aphid predators or their residues impede searching and oviposition by the aphid parasitoid Aphidius ervi hymenoptera aphidiinae
Insect Science, 2014Co-Authors: Raki Almohamad, Thierry HanceAbstract:Intraguild predation (IGP) can be an important factor influencing the effectiveness of aphid natural enemies in biological control. In particular, aphid parasitoid foraging could be influenced by the presence of predators. This study investigated the effect of larvae of the predatory hoverfly Episyrphus balteatus DeGeer (Diptera: Syrphidae) and the multicolored Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae) on the foraging behavior of the aphid parasitoid, Aphidius ervi Haliday (Hymenoptera: Aphidiidae) in choice experiments using a leaf disc bioassay. Wasp response to chemical tracks left by those predator larvae was also tested. Parasitoid behavior was recorded using the Observer (Noldus Information Technology, version 5.0, Wageningen, the Netherlands). The experiments were conducted under controlled environmental conditions using leaves of the broad bean plant, Vicia faba L. (Fabaceae) with Myzus persicae Sulzer (Homoptera: Aphididae) as the host complex. A. ervi females avoided aphid patches when larvae of either predator were present. A similar avoidance response was shown by A. ervi to aphid patches with E. balteatus larval tracks, whereas no significant response was observed to tracks left by H. axyridis larvae. It was concluded that IG predator avoidance shown by the aphid parasitoid A. ervi may be a factor affecting their distribution among host patches. © 2013 Institute of Zoology, Chinese Academy of Sciences.
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optimisation of a semiochemical slow release alginate formulation attractive towards Aphidius ervi haliday parasitoids
Pest Management Science, 2012Co-Authors: Stephanie Heuskin, Isabelle Frere, Pascal Leroy, Eric Haubruge, Stephanie Lorge, Bruno Godin, Francois Verheggen, Jeanpaul Wathelet, Michele Mestdagh, Thierry HanceAbstract:BACKGROUND: Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting predators and parasitoids of aphids. Various formulation criteria were optimised with respect to semiochemical encapsulation capacity. Moreover, the optimised formulation was characterised by texturometry and confocal microscopy. The slow-release rates of semiochemicals were calculated in laboratory controlled conditions. The attractiveness of semiochemical formulations towards Aphidius ervi was demonstrated by olfactometry. RESULTS: Two major parameters were highlighted in encapsulation optimisation: the type of alginate (Sigma L) and the type of crosslinker ion (Ca2+ ). Other formulation parameters were optimised: ionic strength (0.5 M), Ca2+ (0.2 M) and alginate (1.5%) concentrations and the maturation time of beads in CaCl2 solution (48 h). After physical characterisation of beads, semiochemical slow-release measurements showed that alginate formulations were efficient sesquiterpene releasers, with 503 μg of E-β-farnesene and 1791 μg of E-β-caryophyllene totally released in 35 days. The efficiency of semiochemical alginate beads as attractants for female parasitoids was demonstrated, with high percentages of attraction for semiochemical odours (88 and 90% for E-β-farnesene and E-β-caryophyllene respectively) and significant statistical results. CONCLUSION: Semiochemical alginate beads can be considered as efficient slow-release systems in biological control. These formulations could be very useful to attract aphid parasitoids on crop fields.
M Mackauer - One of the best experts on this subject based on the ideXlab platform.
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Variation in selected life-history parameters of the parasitoid wasp,Aphidius ervi: Influence of host developmental stage
Entomologia Experimentalis et Applicata, 1994Co-Authors: R Sequeira, M MackauerAbstract:We determined the age-specific fecundity and survival of the solitary parasstoid wasp, Aphidius ervi Haliday (Hymenoptera: Aphidiidae), under constant laboratory conditions. Wasps were reared in each of the four nymphal instars of apterous pea aphids, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae): L_1 (age 24h), L_2 (48 h), L_3 (72 h), and L_4 (120 h). Age-specific survival (l_x) and fecundity (m_x) differed between parasitoids developing in different aphid instars. The wasps’ life-time reproductive success, as indexed by the intrinsic rate of population increase (r_m), varied non-linearly with adult biomass and host size at parasitization. A close agreement between larval growth rates in different host instars and adult reproductive performance suggests that, in A. ervi , fitness correlates may be significantly influenced by larval ontogeny and trade-offs in resource allocation.
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seasonal variation in body size and offspring sex ratio in field populations of the parasitoid wasp Aphidius ervi hymenoptera aphidiidae
Oikos, 1993Co-Authors: R Sequeira, M MackauerAbstract:We evaluated seasonal variations in body mass and sex ratio in field populations of Aphidius ervi Haliday (Hymenoptera: Aphidiidae), a solitary parasitoid of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae). Parasitoid dry mass was sexually dimorphic, with females being larger than males. Sexual size dimorphism was independent of host instar at parasitization. Parasitoid mass varied seasonally, being highest early and late in the season. The population sex ratio was female-biased, with a seasonal mean of 65.7% females (95% confidence interval, 63.8%-67.6%). As predicted by evolutionary host-size models, a greater proportion of female wasps emerged from large than small hosts early (but not late) in the season
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quantitative genetics of body size and development time in the parasitoid wasp Aphidius ervi hymenoptera aphidiidae
Canadian Journal of Zoology, 1992Co-Authors: R Sequeira, M MackauerAbstract:Body size and development time are key components of life-history strategies and fitness in parasitoid wasps. To assess the relative importance of phenotypic variability for fitness, we determined the heritabilities and reaction norms of body size (= dry mass) and development time in Aphidius ervi, a solitary parasitoid of the pea aphid. We estimated the variance components for body size from an ANOVA model for haplodiploidy, using a half-sib design, with each of 18 sires mated to 2 or 3 dams. Phenotypic expression of body size was strongly influenced by host size (= instar) at the time of parasitization. Heritability for body size in female A. ervi, averaged over sire and dam components, was 0.38. Although the heritability for development time could not be estimated precisely, a larger dam than sire component suggests that development time has lower heritability than body size. Differences between the heritability estimates for body size in males and females indicate that the mode of inheritance and phen...
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influence of superparasitism on development rate and adult size in a solitary parasitoid wasp Aphidius ervi
Functional Ecology, 1992Co-Authors: M MackauerAbstract:We tested the assumption that superparasitism by solitary species of parasitoid wasps has no fitness consequences For the surviving larva. Using Aphidius ervi and its aphid host, Acyrthosiphon pisum, as an experimental system, we compared adult dry mass and development time from oviposition to adult eclosion between male wasps that developed in single- and in superparasitized aphids. Parasitoids gained 14% more dry mass (with no increase in development time) in superparasitized hosts. It is suggested that superparasitized aphids have higher growth potential for the surviving parasitoid larva because they ingest more food than single-parasitized and unparasitized aphids, in that order
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decision to superparasitize based on larval survival competition between aphid parasitoids Aphidius ervi and Aphidius smithi
Entomologia Experimentalis Et Applicata, 1991Co-Authors: H Mcbrien, M MackauerAbstract:Abstract Oviposition by a parasitoid wasp in an already parasitized host (= superparasitism) may result in larval competition and the loss of offspring. Consequently, in solitary species, the decision to superparasitize should be based on the probability of offspring survival. Females of Aphidius ervi Haliday and A. smithi Sharma & Subba Rao (Hymenoptera: Aphidiidae), two parasitoids of the pea aphid, discriminated between conspecific- and heterospecific-parasitized hosts. Both species showed partial preference for aphids previously attacked by A. smithi, a result predicted from the fact that A. ervi is superior to A. smithi in larval competition under most conditions. Females of A. smithi selectively attacked conspecific-parasitized pea aphids when given a choice between these and self-parasitized hosts. Results indicated that females of both species responded to an external pheromone-like marker to discriminate between self-, conspecific- and heterospecific-parasitized aphids. In addition, A. smithi may use internal cues to recognize, and avoid oviposition in, aphids previously parasitized by A. ervi. Resume La decision de superparasiter basee sur la survie larvaire: competition entre les parasites du puceron du pois Aphidius ervi et Aphidius smithi L'oviposition par une guepe parasite dans un hote qui a deja ete parasite (= superparasitisme) pourrait conduire a une competition entre larves et a une perte de progeniture. Par consequent, dans les especes solitaires, la decision de superparasiter devrait etre basee sur la probabilite de survie de la progeniture. Les femelles de Aphidius ervi Haliday et de A. smithi Sharma & Subba Rao (Hymenoptera: Aphidiidae), deux parasites du puceron du pois, ont discrimine entre les hotes parasites par des individus de la meme espece et ceux parasites par des individus d'une espeece differente. Les deux especes de parasite ont montre une preference partielle pour les pucerons prealablement parasites par A. smithi, resultat qui etait previsible du fait que, dans la majorite des cas, A. ervi est superieur a A. smithi dans la competition entre larves. Les femelles de A. smithi ont selectivement attaque les pucerons parasites par un individu de la meme espece lorsqu'il leur etait donne de choisir parmi ceux-ci et ceux parasites par les meme individu. Les resultats indiquaient que les femelles des deux especes repondaient a une sorte de pheromone externe pour distinguer les pucerons parasites par le meme individu de ceux parasites par un individu de la meme espece et ceux parasites d'une autre espece. En plus, A. smithi pourrait utiliser des signaux internes pour reconnaitre et eviter l'oviposition dans les pucerons prealablement parasites par A. ervi.
