Search results for "host"

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…

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…

Western European Populations of the Ichneumonid Wasp Hyposoter didymator Belong to a Single Taxon

2019

Hyposoter didymator (Hymenoptera, Ichneumonidae) is a generalist solitary endoparasitoid of noctuid larvae. In the present work, we tested whether populations of H. didymator were divided in several genetically distinct taxa as described for many other generalist parasitoid species, and whether differences in H. didymator parasitism rates were explained by the insect host species and/or by the plant on which these hosts were feeding on. The genetic analysis of natural populations collected in different regions in France and Spain on seven different insect hosts and seven different host plants (775 individuals) showed that H. didymator populations belong to a unique single taxon. However, H.…

Plant surface mediates interaction between true bug chemical footprints and scelionid egg parasitoids

2009

Chemical footprints left behind by true bugs act as contact kairomones inducing an arrestment response in scelionid egg parasitoids. Once in contact with contaminated substrates, female wasps display a characteristic arrestment posture followed by an increase of the host searching time. Previous studies were conducted on artificial substrates as filter papers, so that little is known about the effects of natural substrates on behavioural response by wasps. In field, the substrate where these interactions occur, i.e. the surface of plants, is covered by wax layers that can have a role in trophic interactions between insects. In this study, we investigated the influence of plant surfaces on a…

Strelitzia nicolai (Strelitziaceae), new host plant for Rhynchophorus ferrugineus (Coleoptera Curculionidae) in Sicily.

2015

The Red Palm Weevil Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera Curculionidae), is con- sidered the main palm pest in the Mediterranean basin. This species is native to Southeastern Asia and is now widely spread throughout Oceania, Africa, Europe and the Caribbean (MURPHY & BRISCOE, 1999; EPPO, 2008, 2012; CHEBBI et al., 2011; RODA et al., 2011). Moreover, in North America the pest was found in California, where it is now considered eradicated (CDFA, 2010; IPPC, 2015). In Italy the first registered sightings were on nursery palms in Tuscany (SACCHETTI et al., 2005, 2006) and on ornamental palms in urban areas in Sicily (LONGO & TAMBURINO, 2005; LO VERDE & MASSA, 2007). Afterwards,…

Endogenous and exogenous factors affecting the host chemical footprint’s exploitation of an egg parasitoid

2013

During the host location process, parasitoids encounter and explore a great variety of volatile and contact semiochemicals from the host-plant complex. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, when wasps land on a plant, they can taste chemical footprints left by walking adult hosts. These cues represent a set of indirect host-related contact kairomones that induce arrestment and motivated searching behavior, as they drive wasps in an area where there is a high probability of finding hosts but are not able to “promise” the presence of the suitable host stage. Patch time allocation is strongly modified by experience gained during foraging on host traces. In fa…

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…

Behavioral responses of the parasitoid Melittobia digitata to volatiles emitted by its natural and laboratory hosts

2010

Responses of macropterous females of the ectoparasitoid Melittobia digitata Dahms (Hymenoptera: Eulophidae) to direct and indirect cues emitted by its natural hosts as well as laboratory hosts were investigated using a Y-tube olfactometer. To locate the nest ofmud dauber wasps, Trypoxylon politum Say (Hymenoptera: Crabronidae), and one of their inquilines, Anthrax spec., parasitoids exploit volatiles from the freshly built nest mud and the empty cocoon constructed by the wasps, as well as their meconium. However, the parasitoids did not respond to odors emitted by older nest mud or by the host stages that are attacked (T. politum prepupae and Anthrax spec. larvae). Melittobia digitata was n…

Host specificity in the egg parasitoid Telenomus busseolae is mediated by sex pheromone compounds

2007

Several studies showed that egg parasitoids are able to detect host sex pheromones produced by adult hosts as a host cue. In this way female wasps are directed toward an area where host mating is in progress and where an oviposition has probably taken place or is soon to occur. Telenomus busseolae Gahan (Hymenoptera: Scelionidae) is a solitary egg parasitoid of various noctuids (Lepidoptera, Noctuidae) belonging to the genera Sesamia. In field observations, it has been demonstrated that T. busseolae reacts to the pheromone emitted by females of the corn stalk borer, Sesamia nonagrioides (Lefebvre) and the pink stem borer, Sesamia calamistis (Hampson). It is known that the sex pheromone prod…

Contenimento naturale di Bactrocera oleae (Rossi): clima o parassitoidi? Confronto tra Western Cape (Sud Africa) e Sicilia

2017

Bactrocera oleae (Rossi), mosca delle olive, è presente anche in Sud Africa, ma finora non si sono avute notizie di infestazioni economicamente rilevanti negli oliveti. L’accertata presenza di un maggior numero di braconidi parassitoidi della mosca delle olive rispetto alle aree mediterranee è stata ed è considerata da molti autori la principale causa di queste minori infestazioni, senza che però siano stati eseguiti in Sud Africa adeguati studi sulle infestazioni da B. oleae e sui fattori cli- matici delle aree interessate. Analizzando recenti dati sui livelli d’infestazione di B. oleae registrati su olivo coltivato e selvatico nel Western Cape e in Sicilia, appaiono simili in una norm…