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Stefano Colazza - One of the best experts on this subject based on the ideXlab platform.
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Egg Parasitoid exploitation of plant volatiles induced by single or concurrent attack of a zoophytophagous predator and an invasive phytophagous pest
Scientific Reports, 2019Co-Authors: Stefano Colazza, Jacques Brodeur, Letizia Martorana, Maria Cristina Foti, Alfonso Agro, Ezio PeriAbstract:Zoophytophagous insect predators can induce physiological responses in plants by activating defence signalling pathways, but whether plants can respond to facultative phytophagy by recruiting natural enemies remains to be investigated. In Y-tube olfactometer bioassays, using a system including a Vicia faba plant, the zoophytophagous predator Podisus maculiventris and the Egg Parasitoid Telenomus podisi, we first demonstrated that T. podisi females are attracted by broad bean plants damaged by feeding activity of P. maculiventris and on which host Egg masses had been laid, while they are not attracted by undamaged plants or plants damaged by feeding activity alone. In a second experiment, we evaluated the impact of the invasive phytophagous pest Halyomorpha halys on this plant volatile-mediated tritrophic communication. Results showed that the invasive herbivorous adults do not induce plants to recruit the native Egg Parasitoid, but they can disrupt the local infochemical network. In fact, T. podisi females are not attracted by volatiles emitted by plants damaged by H. halys feeding alone or combined with oviposition activity, nor are they attracted by plants concurrently infested by P. maculiventris and H. halys, indicating the specificity in the Parasitoid response and the ability of the invasive herbivore in interrupting the semiochemical communication between plants and native Egg Parasitoids. To the best of our knowledge, this is the first study showing that zoophytophagous predator attacks induce indirect plant defences similarly to those defence strategies adopted by plants as a consequence of single or concurrent infestations of herbivorous insects.
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Mating Status of an Herbivorous Stink Bug Female Affects the Emission of Oviposition-Induced Plant Volatiles Exploited by an Egg Parasitoid
Frontiers in Physiology, 2019Co-Authors: Gianandrea Salerno, Eric Conti, Ezio Peri, Stefano Colazza, Francesca Frati, Antonino CusumanoAbstract:Insect Parasitoids are under selection pressure to optimize their host location strategy in order to maximize fitness. In Parasitoid species that develop on host Eggs, one of these strategies consists in the exploitation of oviposition-induced plant volatiles (OIPVs), specific blends of volatile organic compounds released by plants in response to Egg deposition by herbivorous insects. Plants can recognize insect oviposition via elicitors that trigger OIPVs, but very few elicitors have been characterized so far. In particular, the source and the nature of the elicitor responsible of Egg Parasitoid recruitment in the case of plants induced with oviposition by stink bugs are still unknown. In this paper, we conducted behavioral and molecular investigations to localize the source of the elicitor that attracts Egg Parasitoids and elucidate the role of host mating in elicitation of plant responses. We used as organism study model a tritrophic system consisting of the Egg Parasitoid Trissolcus basalis, the stink bug host Nezara viridula and the plant Vicia faba. We found that Egg Parasitoid attraction to plant volatiles is triggered by extracts coming from the dilated portion of the stink bug spermathecal complex. However, attraction only occurs if extracts are obtained from mated females but not from virgin ones. Egg Parasitoid attraction was not observed when extracts coming from the accessory glands (mesadene and ectadene) of male hosts were applied, either alone or in combination to plants. SDS-PAGE electrophoresis correlated with olfactometer observations as the protein profile of the dilated portion of the spermathecal complex was affected by the stink bug mating status suggesting post-copulatory physiological changes in this reproductive structure. This study contributed to better understanding the host location process by Egg Parasitoids and laid the basis for the chemical characterization of the elicitor responsible for OIPV emission.
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Effects of water stress on emission of volatile organic compounds by Vicia faba, and consequences for attraction of the Egg Parasitoid Trissolcus basalis
Journal of Pest Science, 2017Co-Authors: Gianandrea Salerno, Stefano Colazza, Francesca Frati, Giovanni Marino, Luisa Ederli, Stefania Pasqualini, Francesco Loreto, Mauro CentrittoAbstract:When plants are damaged by herbivorous insects, blends of volatile organic compounds (VOCs) are induced and released and can also be used by Parasitoids to locate hosts. The aim was to determine whether VOCs induced by water stress affect the plant–herbivore–Parasitoid system represented by broad bean (Vicia faba; Fabales: Fabaceae) stink bug (Nezara viridula; Heteroptera: Pentatomidae) Egg Parasitoid (Trissolcus basalis; Hymenoptera: Platygastridae). The effects of water stress (expressed as the percentage fraction of transpirable soil water [FTSW] supplied) alone and in combination with N. viridula damage (feeding plus oviposition) were determined according to: (1) the behavioural response of the Egg Parasitoid in a Y-tube olfactometer and (2) the plant VOCs collected and analysed by thermal desorption–gas chromatography–mass spectrometry. With pot water capacity as FTSW100, water stress was applied as mild (FTSW80), moderate (FTSW50) and severe (FTSW10). Bioassays with plants under abiotic stress alone showed that Egg Parasitoids are more attracted by FTSW10 plants than by well-watered plants. When plants were under abiotic and biotic stress interactions, the Egg Parasitoids are more attracted by FTSW10 and FTSW50 plants than by well-watered plants infested with N. viridula. Considering VOCs emissions, projection to latent structures discriminant analysis (PLS-DA) separated treatments according to Egg Parasitoid responses. Water stress alone and in combination with biotic stress induced changes in VOC emissions of V. faba plants that attract Egg Parasitoids. These findings contribute to our understanding of how water stress affects the interactions between plants, insect pests and Egg Parasitoids.
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The response of an Egg Parasitoid to substrate-borne semiochemicals is affected by previous experience
Scientific Reports, 2016Co-Authors: Ezio Peri, Eric Conti, Stefano Colazza, Gianandrea Salerno, Francesca Frati, Takoua Slimani, Antonino CusumanoAbstract:Animals can adjust their behaviour according to previous experience gained during foraging. In Parasitoids, experience plays a key role in host location, a hierarchical process in which air-borne and substrate-borne semiochemicals are used to find hosts. In nature, chemical traces deposited by herbivore hosts when walking on the plant are adsorbed by leaf surfaces and perceived as substrate-borne semiochemicals by Parasitoids. Chemical traces left on cabbage leaves by adults of the harlequin bug (Murgantia histrionica) induce an innate arrestment response in the Egg Parasitoid Trissolcus brochymenae characterized by an intense searching behaviour on host-contaminated areas. Here we investigated whether the T. brochymenae response to host walking traces left on leaf surfaces is affected by previous experience in the context of Parasitoid foraging behaviour. We found that: 1) an unrewarded experience (successive encounters with host-contaminated areas without successful oviposition) decreased the intensity of the Parasitoid response; 2) a rewarded experience (successful oviposition) acted as a reinforcing stimulus; 3) the elapsed time between two consecutive unrewarded events affected the Parasitoid response in a host-gender specific manner. The ecological role of these results to the host location process of Egg Parasitoids is discussed.
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Egg Parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.
Frontiers in Plant Science, 2014Co-Authors: Rihem Moujahed, Eric Conti, Antonino Cusumano, Ezio Peri, Gianandrea Salerno, Francesca Frati, Stefano ColazzaAbstract:Plants respond to insect oviposition by emission of oviposition-induced plant volatiles (OIPVs) which can recruit Egg Parasitoids of the attacking herbivore. To date, studies demonstrating Egg Parasitoid attraction to OIPVs have been carried out in tritrophic systems consisting of one species each of plant, herbivore host, and the associated Egg Parasitoid. Less attention has been given to plants experiencing multiple attacks by host and non-host herbivores that potentially could interfere with the recruitment of Egg Parasitoids as a result of modifications to the OIPV blend. Egg Parasitoid attraction could also be influenced by the temporal dynamics of multiple infestations, when the same non-host herbivore damages different organs of the same plant species. In this scenario we investigated the responses of Egg Parasitoids to feeding and oviposition damage using a model system consisting of Vicia faba, the above-ground insect herbivore Nezara viridula, the above- and below-ground insect herbivore Sitona lineatus, and Trissolcus basalis, a natural enemy of N. viridula. We demonstrated that the non-host S. lineatus disrupts wasp attraction toward plant volatiles induced by the host N. viridula. Interestingly, V. faba damage inflicted by either adults (i.e. leaf-feeding) or larvae (i.e. root-feeding) of S. lineatus, had a similar disruptive effect on T. basalis host location, suggesting that a common interference mechanism might be involved. Neither naive wasps or wasps with previous oviposition experience were attracted to plant volatiles induced by N. viridula when V. faba plants were concurrently infested with S. lineatus adults or larvae. Analysis of the volatile blends among healthy plants and above-ground treatments show significant differences in terms of whole volatile emissions. Our results demonstrate that induced plant responses caused by a non-host herbivore can disrupt the attraction of an Egg Parasitoid to a plant that is also infested with its host.
Guy Boivin - One of the best experts on this subject based on the ideXlab platform.
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Sex ratio variations with temperature in an Egg Parasitoid: behavioural adjustment and physiological constraint
Animal Behaviour, 2014Co-Authors: Joffrey Moiroux, Jacques Brodeur, Guy BoivinAbstract:Sex allocation in haplodiploid arthropods is a central fitness-related decision that has received much attention in insect Parasitoids. The effect of temperature on the reproductive strategy of female para-sitoids has rarely been addressed, despite evidence of its influence on other fitness-related traits. We explored mechanisms inducing the higher production of males typically observed at low and high temperature in parasitic wasps, considering that this pattern may result from both behavioural adjustment and physiological constraint. By observing the oviposition behaviour of an Egg Parasitoid, Tricho-gramma euproctidis, we were able to distinguish the sex ratio intended by the female from the secondary sex ratio, thereby discriminating between a change in behaviour and a physiological constraint on Egg fertilization. More males emerged from Eggs laid at low (þ45%) or high (þ80%) temperature than at medium temperature, but the underlying mechanisms differed between the two conditions. We observed a behavioural change in sex allocation at high temperature, suggesting that laying of sons may be advantageous at high temperature. At low temperature, the females' intended sex ratio was similar to that at medium temperature, but physiological constraints prevented Egg fertilization during oviposition, resulting in more males emerging from Eggs intended to be females. To our knowledge this is the first experimental evidence that temperature modulates both sex allocation and physiological constraints in Egg fertilization in Parasitoids.
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Size-induced reproductive constraints in an Egg Parasitoid
Journal of Insect Physiology, 2012Co-Authors: Guy Boivin, Véronique MartelAbstract:Abstract The size of adult Parasitoids is influenced by the quantity and quality of resources available during immature development. Gregarious development of endoParasitoids results in scramble competition where the resources are shared among individuals developing into the same host. Individuals that developed gregariously are therefore smaller and that reduced size generally translates into lower fitness due to reductions in several life history traits including longevity, mobility and traits linked to reproduction. We measured the reproductive constraints induced by size in Anaphes listronoti (Hymenoptera: Mymaridae), a facultative gregarious Egg Parasitoid of Curculionidae. Size decreased with number of immatures developing in a host Egg for both male and female A. listronoti. This reduction in size induced a reproductive cost as both males and females produced fewer gametes when developing gregariously. Contrarily to other Egg Parasitoids, A. listronoti males are not prospermatogenic and produced some sperm during their adult life. Their spermatogeny index is estimated at 0.6–0.7 that places this species as moderately synspermatogenic. Female A. listronoti have an ovigeny index of 0.70 and are therefore moderately synovigenic. Large females that developed singly received a full sperm complement only when mated by a large male that also developed singly. When mating with a small triplet male, a large female received less than half her sperm complement. Large males were able to mate three females before the number of sperm transferred started to decrease.
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Gamete number and size correlate with adult size in the Egg Parasitoid Trichogramma euproctidis
Entomologia Experimentalis et Applicata, 2011Co-Authors: Léna Durocher-granger, Véronique Martel, Guy BoivinAbstract:In Parasitoids, the size of the adult is influenced by the size and quality of the host in which it develops. Body size is generally positively correlated with several adult fitness proxies (fecundity, longevity, and mating capacity). The initial resources available to an individual can influence gamete production (sperm and oocytes), and the number and quality of gametes produced directly influence the expected fitness of both males and females. Gamete production in relation to adult body size was quantified in Trichogramma euproctidis (Girault) (Hymenoptera: Trichogrammatidae), a short-lived Egg Parasitoid of lepidopteran species. To avoid host quality variation, male and female Parasitoids of different body sizes were produced using superparasitism by allowing mated and virgin female Parasitoids to oviposit on Trichoplusia ni Hu¨bner (Lepidoptera: Noctuidae) Eggs. Seminal vesicles and ovaries of their offspring were dissected to count oocytes and to measure sperm length and oocytes volume. Tibia length was also measured to estimate body size. The number of oocytes, volume of oocytes, maternal investment index [= (number of oocytes * mean volume of oocytes) ⁄ 10 000] and sperm length were all significantly positively correlated to body size. These results show that initial resources acquired during larval stage induce phenotypic plasticity in gamete production in both male and female T. euproctidis. Whereas number of sperm and oocytes can influence the fitness of males and females through increased mating capacity and fecundity, variation in gamete size (sperm length and oocyte volume) could also affect the fitness of an individual through sperm and larval competition.
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Patch exploitation strategy by an Egg Parasitoid in constant or variable environment
Ecological Entomology, 2005Co-Authors: Joan Van Baaren, Guy Boivin, Yannick OutremanAbstract:1. In this paper, the foraging behaviour (the proximal mechanisms involved in patch-leaving rules and the Egg dispersion) of an Egg Parasitoid, Anaphes victus, was analysed in environments containing either patches of constant quality (i.e. predictable environment) or patches of variable quality (i.e. unpredictable environment) in order to determine the motivational mechanisms used in patch-leaving strategies.2. Comparison of the patch exploitation strategy of A. victus between the different habitats suggested that the response of A. victus to a given patch quality strongly depended on its past experiences. Females allocated more time and more Eggs in a mixed quality patch after experiencing a poor quality patch than after experiencing a good quality patch. In a poor quality patch, females superparasitised more frequently after experiencing a poor quality patch than after experiencing a good quality patch. In a good quality patch, A. victus females laid more Eggs after having visited two poor quality patches than after visiting good quality patches.3. Recent foraging experiences are used to estimate both the availability and spatial distribution of hosts in the environment and adjust foraging decisions accordingly. The observed variability in the patch-leaving rules within the same species stresses the importance of previous experience when describing behaviours of female Parasitoids.
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costs and benefits of polyandry in the Egg Parasitoid trichogramma evanescens westwood hymenoptera trichogrammatidae
Biological Control, 2005Co-Authors: Sebastien Jacob, Guy BoivinAbstract:Abstract Polyandry implies costs (i.e., time, energy, predation risk, etc.) especially in short-lived Parasitoid species but females of several hymenopteran Parasitoid species, mostly gregarious, do mate with multiple males. Several hypotheses have been proposed to explain the benefits of polyandry but controversy remains, especially in facultative gregarious species that bridge the gap between solitary and gregarious development. In this study, we investigated the possibility that polyandry may bring material benefits to Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) females, a short-lived and facultative gregarious Egg Parasitoid. Females mated several times with different males both at emergence and throughout their life. No significant difference was found in the offspring sex ratio and the fecundity of multiple mated and single mated females and pre-mating duration increased with the female’s age. The longevity of females did vary significantly with the number of matings but only in the presence of hosts. Female T. evanescens received enough sperm from one mating to allocate an optimal offspring sex ratio and we found no evidence of either nutritional resources or convenience polyandry in this species. Polyandry in facultative gregarious Parasitoids might be an adaptive strategy to minimize the risk of mating with males that have already emptied their sperm bank or to accumulate sperm from several partially sperm-depleted males. Polyandry may also increase the probability of non-sib mating in patches exploited by several females.
Eric Conti - One of the best experts on this subject based on the ideXlab platform.
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an Egg Parasitoid efficiently exploits cues from a coevolved host but not those from a novel host
Frontiers in Physiology, 2019Co-Authors: Eric Conti, Valeria Bertoldi, Gabriele Rondoni, Jacques BrodeurAbstract:Egg Parasitoids have evolved adaptations to exploit host-associated cues, especially oviposition-induced plant volatiles and odors of gravid females, when foraging for hosts. The entire host selection process is critical for successful parasitism and relevant in defining host specificity of Parasitoids. We hypothesized that naive Egg Parasitoid females reared on their coevolved host are able to exploit cues related to the coevolved host but not those from a novel host. We used the Egg Parasitoid Trissolcus japonicus, its coevolved host Halyomorpha halys, and the non-coevolved host Podisus maculiventris to evaluate this hypothesis. H. halys, a polyphagous pest native from Eastern Asia, has invaded North America and Europe, resulting in serious damage to crops. T. japonicus is the most effective Egg Parasitoid of H. halys in its native area and thus considered a major candidate for biological control. This Parasitoid was detected in North America and Europe as a result of accidental introductions. Laboratory host range of T. japonicus includes P. maculiventris, an American predatory stink bug used as a biological control agent of several pests. Using T. japonicus reared on its natural host H. halys, we tested in a Y-tube olfactometer the responses of naive Parasitoid females to volatiles from tomato plants with a deposited Egg mass and feeding punctures of either H. halys or P. maculiventris. Additionally, using two different olfactometer set-ups, we tested T. japonicus responses to volatiles emitted by Eggs and mature males and females of H. halys or P. maculiventris. Tomato plants subjected to oviposition and feeding by H. halys were preferred by the wasp compared to clean plants, suggesting a possible activation of an indirect defense mechanism. Furthermore, T. japonicus females were attracted by cues from gravid females and mature males of H. halys but not from Eggs. By contrast, naive Parasitoid females never responded to cues associated with P. maculiventris, although this non-target host is suitable for complete Parasitoid development. Such lack of responses might reduce the probability of T. japonicus locating and parasitizing P. maculiventris under field conditions. Our experimental approach properly simulates the Parasitoid host-location process and could be combined with the required host specificity tests for risk assessment in biological control programs.
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Mating Status of an Herbivorous Stink Bug Female Affects the Emission of Oviposition-Induced Plant Volatiles Exploited by an Egg Parasitoid
Frontiers in Physiology, 2019Co-Authors: Gianandrea Salerno, Eric Conti, Ezio Peri, Stefano Colazza, Francesca Frati, Antonino CusumanoAbstract:Insect Parasitoids are under selection pressure to optimize their host location strategy in order to maximize fitness. In Parasitoid species that develop on host Eggs, one of these strategies consists in the exploitation of oviposition-induced plant volatiles (OIPVs), specific blends of volatile organic compounds released by plants in response to Egg deposition by herbivorous insects. Plants can recognize insect oviposition via elicitors that trigger OIPVs, but very few elicitors have been characterized so far. In particular, the source and the nature of the elicitor responsible of Egg Parasitoid recruitment in the case of plants induced with oviposition by stink bugs are still unknown. In this paper, we conducted behavioral and molecular investigations to localize the source of the elicitor that attracts Egg Parasitoids and elucidate the role of host mating in elicitation of plant responses. We used as organism study model a tritrophic system consisting of the Egg Parasitoid Trissolcus basalis, the stink bug host Nezara viridula and the plant Vicia faba. We found that Egg Parasitoid attraction to plant volatiles is triggered by extracts coming from the dilated portion of the stink bug spermathecal complex. However, attraction only occurs if extracts are obtained from mated females but not from virgin ones. Egg Parasitoid attraction was not observed when extracts coming from the accessory glands (mesadene and ectadene) of male hosts were applied, either alone or in combination to plants. SDS-PAGE electrophoresis correlated with olfactometer observations as the protein profile of the dilated portion of the spermathecal complex was affected by the stink bug mating status suggesting post-copulatory physiological changes in this reproductive structure. This study contributed to better understanding the host location process by Egg Parasitoids and laid the basis for the chemical characterization of the elicitor responsible for OIPV emission.
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The response of an Egg Parasitoid to substrate-borne semiochemicals is affected by previous experience
Scientific Reports, 2016Co-Authors: Ezio Peri, Eric Conti, Stefano Colazza, Gianandrea Salerno, Francesca Frati, Takoua Slimani, Antonino CusumanoAbstract:Animals can adjust their behaviour according to previous experience gained during foraging. In Parasitoids, experience plays a key role in host location, a hierarchical process in which air-borne and substrate-borne semiochemicals are used to find hosts. In nature, chemical traces deposited by herbivore hosts when walking on the plant are adsorbed by leaf surfaces and perceived as substrate-borne semiochemicals by Parasitoids. Chemical traces left on cabbage leaves by adults of the harlequin bug (Murgantia histrionica) induce an innate arrestment response in the Egg Parasitoid Trissolcus brochymenae characterized by an intense searching behaviour on host-contaminated areas. Here we investigated whether the T. brochymenae response to host walking traces left on leaf surfaces is affected by previous experience in the context of Parasitoid foraging behaviour. We found that: 1) an unrewarded experience (successive encounters with host-contaminated areas without successful oviposition) decreased the intensity of the Parasitoid response; 2) a rewarded experience (successful oviposition) acted as a reinforcing stimulus; 3) the elapsed time between two consecutive unrewarded events affected the Parasitoid response in a host-gender specific manner. The ecological role of these results to the host location process of Egg Parasitoids is discussed.
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The role of contact chemoreception in the host location process of an Egg Parasitoid
Journal of Insect Physiology, 2016Co-Authors: Alessia Iacovone, Alice Sarah French, Cyril Gaertner, Eric Conti, Frédérique Tellier, Antonino Cusumano, Gianandrea Salerno, Gilles Clément, Frédéric Marion-pollAbstract:Taste allows insects to detect palatable or toxic foods, identify a mate, and select appropriate oviposition sites. The gustatory system strongly contributes to the survival and reproductive success of many species, yet it is rarely studied in insect Parasitoids. In order to locate and assess a host in which they will lay their Eggs, female wasps actively search for chemical cues using their sensory organs present mainly on the antennae. In this paper, we studied the role of antenna] taste sensilla chaetica in the perception of contact semiochemicals in Trissolcus brochymenae (Hymenoptera: Platygastridae), an Egg Parasitoid of the brassicaceae pest Murgantia histrionica (Heteroptera: Pentatomidae). Methanolic extracts obtained from male and female hosts elicited action potentials in taste neurons housed in antennal sensilla chaetica, indicating that these sensilla are involved in the perception of non volatile host kairomones. In behavioural assays, wasp females displayed an intense searching behaviour in open arenas treated with host extracts, thus confirming that these kairomones are soluble in polar solvents. We further investigated the extracts by Gas Chromatography-Mass Spectrometry (GC-MS) and found that they contain several compounds which are good candidates for these contact kairomones. This study contributes to better understanding contact chemoreception in Egg Parasitoids and identifying gustatory receptor neurons involved in the host location process.
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Egg Parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.
Frontiers in Plant Science, 2014Co-Authors: Rihem Moujahed, Eric Conti, Antonino Cusumano, Ezio Peri, Gianandrea Salerno, Francesca Frati, Stefano ColazzaAbstract:Plants respond to insect oviposition by emission of oviposition-induced plant volatiles (OIPVs) which can recruit Egg Parasitoids of the attacking herbivore. To date, studies demonstrating Egg Parasitoid attraction to OIPVs have been carried out in tritrophic systems consisting of one species each of plant, herbivore host, and the associated Egg Parasitoid. Less attention has been given to plants experiencing multiple attacks by host and non-host herbivores that potentially could interfere with the recruitment of Egg Parasitoids as a result of modifications to the OIPV blend. Egg Parasitoid attraction could also be influenced by the temporal dynamics of multiple infestations, when the same non-host herbivore damages different organs of the same plant species. In this scenario we investigated the responses of Egg Parasitoids to feeding and oviposition damage using a model system consisting of Vicia faba, the above-ground insect herbivore Nezara viridula, the above- and below-ground insect herbivore Sitona lineatus, and Trissolcus basalis, a natural enemy of N. viridula. We demonstrated that the non-host S. lineatus disrupts wasp attraction toward plant volatiles induced by the host N. viridula. Interestingly, V. faba damage inflicted by either adults (i.e. leaf-feeding) or larvae (i.e. root-feeding) of S. lineatus, had a similar disruptive effect on T. basalis host location, suggesting that a common interference mechanism might be involved. Neither naive wasps or wasps with previous oviposition experience were attracted to plant volatiles induced by N. viridula when V. faba plants were concurrently infested with S. lineatus adults or larvae. Analysis of the volatile blends among healthy plants and above-ground treatments show significant differences in terms of whole volatile emissions. Our results demonstrate that induced plant responses caused by a non-host herbivore can disrupt the attraction of an Egg Parasitoid to a plant that is also infested with its host.
Gianandrea Salerno - One of the best experts on this subject based on the ideXlab platform.
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Mating Status of an Herbivorous Stink Bug Female Affects the Emission of Oviposition-Induced Plant Volatiles Exploited by an Egg Parasitoid
Frontiers in Physiology, 2019Co-Authors: Gianandrea Salerno, Eric Conti, Ezio Peri, Stefano Colazza, Francesca Frati, Antonino CusumanoAbstract:Insect Parasitoids are under selection pressure to optimize their host location strategy in order to maximize fitness. In Parasitoid species that develop on host Eggs, one of these strategies consists in the exploitation of oviposition-induced plant volatiles (OIPVs), specific blends of volatile organic compounds released by plants in response to Egg deposition by herbivorous insects. Plants can recognize insect oviposition via elicitors that trigger OIPVs, but very few elicitors have been characterized so far. In particular, the source and the nature of the elicitor responsible of Egg Parasitoid recruitment in the case of plants induced with oviposition by stink bugs are still unknown. In this paper, we conducted behavioral and molecular investigations to localize the source of the elicitor that attracts Egg Parasitoids and elucidate the role of host mating in elicitation of plant responses. We used as organism study model a tritrophic system consisting of the Egg Parasitoid Trissolcus basalis, the stink bug host Nezara viridula and the plant Vicia faba. We found that Egg Parasitoid attraction to plant volatiles is triggered by extracts coming from the dilated portion of the stink bug spermathecal complex. However, attraction only occurs if extracts are obtained from mated females but not from virgin ones. Egg Parasitoid attraction was not observed when extracts coming from the accessory glands (mesadene and ectadene) of male hosts were applied, either alone or in combination to plants. SDS-PAGE electrophoresis correlated with olfactometer observations as the protein profile of the dilated portion of the spermathecal complex was affected by the stink bug mating status suggesting post-copulatory physiological changes in this reproductive structure. This study contributed to better understanding the host location process by Egg Parasitoids and laid the basis for the chemical characterization of the elicitor responsible for OIPV emission.
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Effects of water stress on emission of volatile organic compounds by Vicia faba, and consequences for attraction of the Egg Parasitoid Trissolcus basalis
Journal of Pest Science, 2017Co-Authors: Gianandrea Salerno, Stefano Colazza, Francesca Frati, Giovanni Marino, Luisa Ederli, Stefania Pasqualini, Francesco Loreto, Mauro CentrittoAbstract:When plants are damaged by herbivorous insects, blends of volatile organic compounds (VOCs) are induced and released and can also be used by Parasitoids to locate hosts. The aim was to determine whether VOCs induced by water stress affect the plant–herbivore–Parasitoid system represented by broad bean (Vicia faba; Fabales: Fabaceae) stink bug (Nezara viridula; Heteroptera: Pentatomidae) Egg Parasitoid (Trissolcus basalis; Hymenoptera: Platygastridae). The effects of water stress (expressed as the percentage fraction of transpirable soil water [FTSW] supplied) alone and in combination with N. viridula damage (feeding plus oviposition) were determined according to: (1) the behavioural response of the Egg Parasitoid in a Y-tube olfactometer and (2) the plant VOCs collected and analysed by thermal desorption–gas chromatography–mass spectrometry. With pot water capacity as FTSW100, water stress was applied as mild (FTSW80), moderate (FTSW50) and severe (FTSW10). Bioassays with plants under abiotic stress alone showed that Egg Parasitoids are more attracted by FTSW10 plants than by well-watered plants. When plants were under abiotic and biotic stress interactions, the Egg Parasitoids are more attracted by FTSW10 and FTSW50 plants than by well-watered plants infested with N. viridula. Considering VOCs emissions, projection to latent structures discriminant analysis (PLS-DA) separated treatments according to Egg Parasitoid responses. Water stress alone and in combination with biotic stress induced changes in VOC emissions of V. faba plants that attract Egg Parasitoids. These findings contribute to our understanding of how water stress affects the interactions between plants, insect pests and Egg Parasitoids.
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The response of an Egg Parasitoid to substrate-borne semiochemicals is affected by previous experience
Scientific Reports, 2016Co-Authors: Ezio Peri, Eric Conti, Stefano Colazza, Gianandrea Salerno, Francesca Frati, Takoua Slimani, Antonino CusumanoAbstract:Animals can adjust their behaviour according to previous experience gained during foraging. In Parasitoids, experience plays a key role in host location, a hierarchical process in which air-borne and substrate-borne semiochemicals are used to find hosts. In nature, chemical traces deposited by herbivore hosts when walking on the plant are adsorbed by leaf surfaces and perceived as substrate-borne semiochemicals by Parasitoids. Chemical traces left on cabbage leaves by adults of the harlequin bug (Murgantia histrionica) induce an innate arrestment response in the Egg Parasitoid Trissolcus brochymenae characterized by an intense searching behaviour on host-contaminated areas. Here we investigated whether the T. brochymenae response to host walking traces left on leaf surfaces is affected by previous experience in the context of Parasitoid foraging behaviour. We found that: 1) an unrewarded experience (successive encounters with host-contaminated areas without successful oviposition) decreased the intensity of the Parasitoid response; 2) a rewarded experience (successful oviposition) acted as a reinforcing stimulus; 3) the elapsed time between two consecutive unrewarded events affected the Parasitoid response in a host-gender specific manner. The ecological role of these results to the host location process of Egg Parasitoids is discussed.
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The role of contact chemoreception in the host location process of an Egg Parasitoid
Journal of Insect Physiology, 2016Co-Authors: Alessia Iacovone, Alice Sarah French, Cyril Gaertner, Eric Conti, Frédérique Tellier, Antonino Cusumano, Gianandrea Salerno, Gilles Clément, Frédéric Marion-pollAbstract:Taste allows insects to detect palatable or toxic foods, identify a mate, and select appropriate oviposition sites. The gustatory system strongly contributes to the survival and reproductive success of many species, yet it is rarely studied in insect Parasitoids. In order to locate and assess a host in which they will lay their Eggs, female wasps actively search for chemical cues using their sensory organs present mainly on the antennae. In this paper, we studied the role of antenna] taste sensilla chaetica in the perception of contact semiochemicals in Trissolcus brochymenae (Hymenoptera: Platygastridae), an Egg Parasitoid of the brassicaceae pest Murgantia histrionica (Heteroptera: Pentatomidae). Methanolic extracts obtained from male and female hosts elicited action potentials in taste neurons housed in antennal sensilla chaetica, indicating that these sensilla are involved in the perception of non volatile host kairomones. In behavioural assays, wasp females displayed an intense searching behaviour in open arenas treated with host extracts, thus confirming that these kairomones are soluble in polar solvents. We further investigated the extracts by Gas Chromatography-Mass Spectrometry (GC-MS) and found that they contain several compounds which are good candidates for these contact kairomones. This study contributes to better understanding contact chemoreception in Egg Parasitoids and identifying gustatory receptor neurons involved in the host location process.
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Egg Parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.
Frontiers in Plant Science, 2014Co-Authors: Rihem Moujahed, Eric Conti, Antonino Cusumano, Ezio Peri, Gianandrea Salerno, Francesca Frati, Stefano ColazzaAbstract:Plants respond to insect oviposition by emission of oviposition-induced plant volatiles (OIPVs) which can recruit Egg Parasitoids of the attacking herbivore. To date, studies demonstrating Egg Parasitoid attraction to OIPVs have been carried out in tritrophic systems consisting of one species each of plant, herbivore host, and the associated Egg Parasitoid. Less attention has been given to plants experiencing multiple attacks by host and non-host herbivores that potentially could interfere with the recruitment of Egg Parasitoids as a result of modifications to the OIPV blend. Egg Parasitoid attraction could also be influenced by the temporal dynamics of multiple infestations, when the same non-host herbivore damages different organs of the same plant species. In this scenario we investigated the responses of Egg Parasitoids to feeding and oviposition damage using a model system consisting of Vicia faba, the above-ground insect herbivore Nezara viridula, the above- and below-ground insect herbivore Sitona lineatus, and Trissolcus basalis, a natural enemy of N. viridula. We demonstrated that the non-host S. lineatus disrupts wasp attraction toward plant volatiles induced by the host N. viridula. Interestingly, V. faba damage inflicted by either adults (i.e. leaf-feeding) or larvae (i.e. root-feeding) of S. lineatus, had a similar disruptive effect on T. basalis host location, suggesting that a common interference mechanism might be involved. Neither naive wasps or wasps with previous oviposition experience were attracted to plant volatiles induced by N. viridula when V. faba plants were concurrently infested with S. lineatus adults or larvae. Analysis of the volatile blends among healthy plants and above-ground treatments show significant differences in terms of whole volatile emissions. Our results demonstrate that induced plant responses caused by a non-host herbivore can disrupt the attraction of an Egg Parasitoid to a plant that is also infested with its host.
Jocelyn G. Millar - One of the best experts on this subject based on the ideXlab platform.
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Host defensive response against an Egg Parasitoid involves cellular encapsulation and melanization
Biological Control, 2007Co-Authors: Darcy A. Reed, Katharine A. Luhring, Candice A. Stafford, Allison K. Hansen, Jocelyn G. Millar, Lawrence M. Hanks, Timothy D. PaineAbstract:The Egg Parasitoid Avetianella longoi Siscaro attacks two species of eucalyptus longhorned borers (Phoracantha semipunctata F. and P. recurva Newman) in southern California. During the past decade, P. recurva has replaced P. semipunctata as the dominant borer species, apparently due to differential rates of parasitism. The present study reveals that this replacement is due in part to a physiological defensive response mounted by one species (P. recurva) against Parasitoid Eggs and larvae, similar to the encapsulation/melanization immune response observed in larval host/Parasitoid systems. Fluorescence microscopy and vital dyes confirmed that the defensive response was cellular in nature. Both Phoracantha species exhibited a cellular wound-healing response around the wasp Egg pedicel, but the encapsulation of the wasp Eggs/larvae was elicited only in Eggs of P. recurva. This is the first conclusive evidence that hosts in the Egg stage can mount a cellular immune response against a metazoan Parasitoid, and may provide insight into the mechanisms underlying the host specificity of many Egg Parasitoids.
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identification of volatile synomones induced by nezara viridula feeding and oviposition on bean spp that attract the Egg Parasitoid trissolcus basalis
Journal of Chemical Ecology, 2004Co-Authors: Stefano Colazza, Steven J Mcelfresh, Jocelyn G. MillarAbstract:Bean plants (Vicia faba L. and Phaseolus vulgaris L.) damaged by feeding activity of Nezara viridula (L.) (Heteroptera: Pentatomidae), and onto which an Egg mass had been laid, produced volatiles that attracted the Egg Parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae). Extracts of volatiles of broad bean and French bean plants induced by adults of N. viridula as a result of their feeding activity, oviposition activity, and feeding and oviposition activity combined were analyzed by gas chromatography–mass spectrometry (GC–MS), and tested in Y-tube olfactometer bioassays as attractants for T. basalis females. In extracts from undamaged leguminous plants, green-leaf volatiles were absent or scarcely detected, and monoterpenes and sesquiterpenes were present at trace levels. No significant differences were detected in the profiles of volatiles of undamaged plants, and undamaged plants on which bugs were allowed only to lay Eggs. In contrast, feeding and oviposition by adults of N. viridula induced in both leguminous plants a significant increase in terpenoids such as linalool, (E)-β-caryophyllene, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, and (3E)-4,8-dimethyl-1,3,7-nonatriene, which was induced only in French bean plants. Quantitative comparisons revealed increased levels of (E)-β-caryophyllene in extracts from feeding-damaged plants with N. viridula Egg masses compared to feeding-damaged plants without Egg masses. In Y-tube olfactometer bioassays, T. basalis females were attracted by extracts of both leguminous plants only when N. viridula adults were allowed to feed and oviposit upon them. Fractionation of extracts of volatiles from broad bean plants with N. viridula feeding damage and Egg masses yielded two fractions, but only the fraction containing (E)-β-caryophyllene was attractive to the Egg Parasitoid. These findings indicate that N. viridula feeding and oviposition induce leguminous plants to produce blends of volatiles that are characterized by increased amounts of (E)-β-caryophyllene, and these blends attract female T. basalis. The role of (E)-β-caryophyllene as a potential synomone for T. basalis is discussed.
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identification of volatile synomones induced by nezara viridula feeding and oviposition on bean spp that attract the Egg Parasitoid trissolcus basalis
Journal of Chemical Ecology, 2004Co-Authors: Stefano Colazza, Steven J Mcelfresh, Jocelyn G. MillarAbstract:Bean plants (Vicia faba L. and Phaseolus vulgaris L.) damaged by feeding activity of Nezara viridula (L.) (Heteroptera: Pentatomidae), and onto which an Egg mass had been laid, produced volatiles that attracted the Egg Parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae). Extracts of volatiles of broad bean and French bean plants induced by adults of N. viridula as a result of their feeding activity, oviposition activity, and feeding and oviposition activity combined were analyzed by gas chromatography-mass spectrometry (GC-MS), and tested in Y-tube olfactometer bioassays as attractants for T. basalis females. In extracts from undamaged leguminous plants, green-leaf volatiles were absent or scarcely detected, and monoterpenes and sesquiterpenes were present at trace levels. No significant differences were detected in the profiles of volatiles of undamaged plants, and undamaged plants on which bugs were allowed only to lay Eggs. In contrast, feeding and oviposition by adults of N. viridula induced in both leguminous plants a significant increase in terpenoids such as linalool, (E)-beta-caryophyllene, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, and (3E)-4,8-dimethyl-1,3,7-nonatriene, which was induced only in French bean plants. Quantitative comparisons revealed increased levels of (E)-beta-caryophyllene in extracts from feeding-damaged plants with N. viridula Egg masses compared to feeding-damaged plants without Egg masses. In Y-tube olfactometer bioassays, T. basalis females were attracted by extracts of both leguminous plants only when N. viridula adults were allowed to feed and oviposit upon them. Fractionation of extracts of volatiles from broad bean plants with N. viridula feeding damage and Egg masses yielded two fractions. but only the fraction containing (E)-beta-caryophyllene was attractive to the Egg Parasitoid. These findings indicate that N. viridula feeding and oviposition induce leguminous plants to produce blends of volatiles that are characterized by increased amounts of (E)-beta-caryophyllene, and these blends attract female T. basalis. The role of (E)-beta-caryophyllene as a potential synomone for T. basalis is discussed.