0000000000320281
AUTHOR
Francesca Frati
showing 14 related works from this author
Gli stimoli chimici indiretti dell'ospite nel processo di localizzazione da parte degli oofagi: conviene sintonizzarsi?
2008
Tra gli stimoli indiretti che un parassitoide può utilizzare per ritrovare l'ospite, particolare importanze rivestono per i parassitoidi oofagi le tracce chimiche depositate dai Pentatomidi mentre si muovono su un substrato. Questo segnale chimico induce nelle femmine del parassitoide un comportamento di arresto che ne delimita la ricerca e ne aumenta le possibilità di ritrovamento delle uova. Nel sistema Murgantia histrionica (Heteroptera: Pentatomidae) - Trissolcus brochymenae (Hymenoptera: Scelionidae) si è voluto verificare se lo stato fisiologico dell’ospite influenza lo sfruttamento delle tracce da parte del parassitoide. I biosaggi sono stati condotti in arena aperta, e registrati me…
Egg parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.
2014
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 …
Host chemical footprints induce host sex discrimination ability in egg parasitoids
2013
Trissolcus egg parasitoids, when perceiving the chemical footprints left on a substrate by pentatomid host bugs, adopt a motivated searching behaviour characterized by longer searching time on patches were signals are present. Once in contact with host chemical footprints, Trissolcus wasps search longer on traces left by associated hosts rather than non-associated species, and, in the former case, they search longer on traces left by females than males. Based on these evidences, we hypothesized that only associated hosts induce the ability to discriminate host sex in wasps. To test this hypothesis we investigated the ability of Trissolcus basalis, T. brochymenae, and Trissolcus sp. to disti…
Foraging behaviour of an egg parasitoid exploiting plant volatiles induced by pentatomids : The role of adaxial and abaxial leaf surfaces
2017
Several phases of herbivorous insect attack including feeding and oviposition are known to induce plant defenses. Plants emit volatiles induced by herbivores to recruit insect parasitoids as an indirect defense strategy. So far, volatiles induced by herbivore walking and their putative role in the foraging behavior of egg parasitoids have not been investigated. In this paper we studied the response of the egg parasitoid Trissolcus basalis toward volatiles emitted by Vicia faba plants as consequence of the walking activity of the host Nezara viridula. Olfactometer bioassays were carried out to evaluate wasp responses to plants in which the abaxial or the adaxial surfaces were subjected to wa…
A finely tuned strategy adopted by an egg parasitoid to exploit chemical traces from host adults.
2009
SUMMARY Scelionid egg parasitoids can obtain reliable information on the presence of host eggs by discriminating host gender on the basis of chemical footprints of their co-evolved hosts, with a strong preference for the footprint left by host females. Based on the concept of dietary specialization and infochemical use in natural enemies, it could be predicted that host gender discrimination in specialist species belonging to the genus Trissolcus is further tuned to specific cues from distinctive chemical traces left by host females as a consequence of copulation and/or oviposition. To test this hypothesis we used the system Murgantia histrionica – Trissolcus brochymenae. Our results showed…
A female-produced short-range sex pheromone in the egg parasitoid Trissolcus brochymenae
2012
The potential for short-range sex pheromone communication by the egg parasitoid wasp Trissolcus brochymenae (Hymenoptera: Platygastridae) was investigated in closed arena bioassays. Males of this parasitoid showed more antennal drumming and more frequent mounting behaviour on 1- to 2-d-old virgin females compared with 8-d-old virgin females. Male copulation attempts were fewer with previously mated females than with virgin females. Males courted and made copulation attempts with 1- to 2-d-old female cadavers, but not with male cadavers or with female cadavers rinsed in organic solvents of different polarities. Male attraction to female cadavers was re-established by treating cadavers with a…
The response of an egg parasitoid to substrate-borne semiochemicals is affected by previous experience
2016
AbstractAnimals 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 …
Effects of water stress on emission of volatile organic compounds by Vicia faba, and consequences for attraction of the egg parasitoid Trissolcus bas…
2017
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-para- sitoid system represented by broad bean (Vicia faba; Fabales: Fabaceae) stink bug (Nezara viridula; Hetero- ptera: 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 deter- mined according to: (1) the behavioural r…
Mating Status of an Herbivorous Stink Bug Female Affects the Emission of Oviposition-Induced Plant Volatiles Exploited by an Egg Parasitoid
2019
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 …
Infestation of broad bean (Vicia faba) by the green stink bug (Nezara viridula) decreases shoot abscisic acid contents under well-watered and drought…
2017
The response of broad bean (Vicia faba) plants to water stress alone and in combination with green stink bug (Nezara viridula) infestation was investigated through measurement of: (1) leaf gas exchange; (2) plant hormone titres of abscisic acid (ABA) and its metabolites, and of salicylic acid (SA); and (3) hydrogen peroxide (H2O2) content. Furthermore, we evaluated the effects of experimentally water-stressed broad-bean plants on N. viridula performance in terms of adult host–plant preference, and nymph growth and survival. Water stress significantly reduced both photosynthesis (A) and stomatal conductance (gs), while infestation by the green stink bug had no effects on photosynthesis but s…
Influence of Feeding and Oviposition by Phytophagous Pentatomids on Photosynthesis of Herbaceous Plants
2010
Abstract Feeding by herbivorous insects may change photosynthetic activity of host plants. We studied how feeding and oviposition by herbivorous stink bugs, Murgantia histrionica and Nezara viridula (Heteroptera: Pentatomidae), affect photosynthetic parameters of Brassica oleracea (savoy cabbage) and Phaseolus vulgaris (French bean). First, we measured photosynthetic gas exchange, chlorophyll fluorescence imaging, and emission of induced volatile organic compounds (VOC) immediately after feeding and during a post-feeding period. Photosynthesis decreased rapidly and substantially in B. oleracea and P. vulgaris infested by feeding bugs. Stomatal conductance did not decrease proportionally wit…
Sexual communication in the egg parasitoid Trissolcus brochymenae
2009
The males of the egg parasitoid Trissolcus brochymenae (Hymenoptera Scelionidae) exploit a short range pheromone for recognition of the other gender. To evaluate the role of this pheromone, the behavior of virgin males has been studied in closed arena when exposed to the following cues: 1) virgin females (alive, dead "washed" with solvents, dead" unwashed"); 2) dissected and re-assembled virgin females (females dissected into head, mesosoma, and gaster, then reassembled using two solvent "washed" parts and an "unwashed” part, or "unwashed" legs assembled with entire" washed" body); 3) "washed" females treated with acetone extracts (of virgin females and of legs). Males antennate and mount v…
Il feromone sessuale a breve raggio del parassitoide oofago Trissolcus brochymenae
2009
Il comportamento sessuale dei parassitoidi presenta una fase di pre-copula, in cui si ha ricerca, corteggiamento e riconoscimento dell’altro sesso, alla quale seguono le fasi di copula ed eventualmente post-copula. Durante la pre-copula, la localizzazione e il riconoscimento sono per lo più stimolati da composti feromonali con diversa volatilità. I composti feromonali ad alta volatilità, rilasciati dalle femmine, sono utilizzati dai maschi per l’orientamento a lunga distanza, mentre quelli scarsamente volatili mediano il comportamento di corteggiamento. In questo lavoro si riportano dati sperimentali sul feromone sessuale a breve raggio emesso dalle femmine di Trissolcus brochymenae (Hymeno…
Effetto del grado di coevoluzione e di specializzazione nella capacità di ooparassitoidi ad utilizzare le impronte chimiche dell'ospite
2009
Le impronte chimiche lasciate sul substrato dai Pentatomidi stimolano nei parassitoidi oofagi la ricerca dell’ospite nell’area contaminata e consentono loro di distinguerne il sesso. Le impronte chimiche delle femmine sono preferite poiché risultano più affidabili in quanto nei dintorni è maggiore la probabilità di ritrovare l’uovo ospite. In questo lavoro è stato ipotizzato che l’abilità di discriminare il sesso degli ospiti da parte degli ooparassitoidi è stata acquisita solo nei confronti di quelli coevoluti. Sono state quindi considerate due associazioni di ospite-parassitoide coevoluti quali Nezara viridula-Trissolcus basalis e Murgantia histrionica-Trissolcus brochymenae e come ospite…