Search results for " Trissolcus basalis"

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…

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 …

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 …

Contrasting olfactory responses of two egg parasitoids to buckwheat floral scent are reflected in field parasitism rates

2019

International audience; Conservation biological control programs advocate the planting of flower strips alongside crops to improve the survival and effectiveness of parasitoids. Ideally, the provided food plants are highly attractive and benefit the targeted biocontrol agents without promoting pests or intraguild competition. Previous laboratory studies showed that Trissolcus basalis, an egg parasitoid of the stink bug Nezara viridula, is highly attracted to floral odors of buckwheat and that its nectar increases the wasp’s fecundity. In the field, T. basalis competes with the co-occurring parasitoid Ooencyrtus telenomicida for host eggs. Therefore, in the present study, we explored whether…

An invasive insect herbivore disrupts plant volatile-mediated tritrophic signalling

2017

Plants respond to insect attack by emission of volatile organic compounds, which recruit natural enemies of the attacking herbivore, constituting an indirect plant defence strategy. In this context, the egg parasitoid Trissolcus basalis is attracted by oviposition-induced plant volatiles emitted by Vicia faba plants as a consequence of feeding and oviposition by the pentatomid host Nezara viridula. However, this local tritrophic web could be affected by the recent invasion by the alien pentatomid bug Halyomorpha halys, an herbivore that shares the same environments as native pentatomid pests. Therefore, we investigated in laboratory conditions the possible impact of H. halys on the plant vo…

Contrasting reproductive traits of competing parasitoids facilitate coexistence on a shared host pest in a biological control perspective

2022

BACKGROUND: Interspecific competition in insect parasitoids is an important ecological phenomenon that has relevant implications for biological pest control. To date, interspecific intrinsic (=larval) competition has been intensively studied, while investigations on extrinsic (=adult) competition have often lagged behind. In this study we examined the role played by parasitoid reproductive traits and host clutch size on the outcome of extrinsic competition between Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev), two egg parasitoids of the pest Nezara viridula (L). Laboratory experiments were conducted by allowing both parasitoid species to exploit an egg mass made of …

Intraguild interaction between egg parasitoids: the role of the host egg mass size and parasitoids’ reproductive capacities

2013

In Sicily, field collections of egg masses of the southern green stink bug, Nezara viridula (L.) (Heteroptera:Pentatomidae), revealed that two solitary parasitoids, Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) and Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae), can exploit the same egg mass. Previous finding showed that parasitoid species differ in host location and larval competitive abilities and a host finding-larval competition trade-off may be important for coexistence. The aim of this work was to evaluate the role played by the host egg mass size and the importance of species reproductive capacities in the outcome of interspecific competition. Under labo…

The role of chemical cues in the host finding behaviour of Trissolcus basalis from a Conservation Biological Control perspective

In assessing successful biological control programs by parasitoids, the knowledge of important traits, such as the host finding capability, i.e. the ability to find host and food resources, play the key role. Moreover, parasitoids in their natural environment parasitoids deal with a variable mixtures of natural cues. Some chemical cues are used by the wasps to locate their hosts, some ones drive wasps to feeding resources. The parasitoid response to these cues can fluctuate according to biotic factors and abiotic condition. This dissertation focus in details on the role of two important tools, such as selective flowering plants as food resources to add within a crop area and the traces left…

Effetto della localizzazione dello stress biotico sulle difese indotte in Vicia faba

2016

Le diverse fasi che caratterizzano l’attacco della pianta da parte del fitofago (contatto, alimentazione ed ovideposizione) inducono l’attivazione di meccanismi di difesa nell’ospite. E’ noto che le piante emettono composti volatili indotti in seguito all’attacco del fitofago e che questi volatili sono in grado di richiamare i parassitoidi. Nel caso specifico degli ooparassitoidi, tali difese indirette si esplicitano mediante rilascio di HIPV (herbivore-induced plant volatiles) ed in particolare di OIPV (oviposition-induced plant volatiles). Ad oggi non ci sono studi inerenti il ruolo giocato dalle tracce rilasciate dal fitofago sulla superficie vegetale nell’induzione di volatili utilizzat…

Foraging behaviour of a scelionid egg parasitoid exploiting chemical footprints from associated and non-associated host

2017

Chemical footprints deposited by herbivorous pentatomid host bugs hosts when walking on the plant are adsorbed by leaf surfaces and perceived as substrate borne semiochemicals by scelionid egg parasitoids during host selection process. They act as indirect host-related cues, as they are not able to “promise” to parasitoid females the presence of the suitable host stage, but they drive them in the areas where their hosts are potentially present. Once in contact with host chemical footprints, scelionid wasps evidence an innate arrestment response characterized by an intense searching behaviour on host-contaminated areas. Exploiting of these cues allows the parasitoids to optimize their search…