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Impact of invasive alien true bug species in native tropich webs

Periodic Reporting for period 1 - INVASIoN (Impact of invasive alien true bug species in native tropich webs)

Okres sprawozdawczy: 2016-03-01 do 2018-02-28

When invasive herbivorous insect species invade new environments, they can not only cause serious economic losses to attacked economically important crops, but they also interact with local species, modifying the structure of local food webs with effects cascading across trophic levels.
The INVASION project, by adopting a multidisciplinary approach to study the ecological impact of an alien insect invasion, investigates both the basic and applied consequences determined by the brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Heteroptera: Pentatomidae), which is a pest of Asian origin that has recently invaded both North America and Europe, causing severe economic losses in orchards and field crops.
The main project objectives are: 1) to evaluate the impact of alien herbivore invasion on local tritrophic interactions; 2) to evaluate the responses of parasitoids to infochemical evolutionary traps in a climate change context; 3) to study the contest behaviour of local egg parasitoids for possession of co-evolved and non-coevolved hosts; 4) to investigate the patch time allocation of local egg parasitoids after alien herbivore invasion using behavioural and modelling approaches; 5) to elucidate the molecular aspects of indirect plant defences against invasive and local pest species; 6) to investigate the genetic structure of invasive alien herbivores across Europe and North America.
The invasion of a common pest in different continents, as the BMSB, poses serious threat to numerous agro-ecosystems. In this view, the project aims to achieve a deep understanding of the interactions among the alien pest and other insect community members associated with the same focal crop in order to identify eco-friendly management tactics that can successfully control and reduce the pest status of native and invasive alien true bug species.
The activities proposed in the INVASION project require a multidisciplinary approach that includes knowledge of biological control, behavioural and chemical ecology, invasive ecology, statistical and mathematical modelling, and genetic structure of insect populations.
The Consortium involved in the project provides a combination of scientists from Europe and North America to address key scientific issues related to basic and applied ecology of an invasive herbivore species, which poses serious risks to agriculture. The research units of the Consortium based in Europe are: University of Palermo (UNIPA) - Italy, University of Perugia (UNIPG) - Italy, University of Nottingham (UNINOT) – United Kingdom, Institut National de la Recherche Agronomique (INRA) - France, Benaki Phytopathological Institute (BPI) – Greece. The North American research units are located in Canada at the Université de Montréal (UDEM) - Canada and Agriculture and at the Agri-Food Canada (AAFC).

This multidisciplinary approach has the goal to advance the state of the art in the field of invasive ecology of herbivore pests in order develop effective biological control programmes.
The project was structured into the following six work packages:
WP1 - Impact of alien herbivore invasion on local tritrophic interactions;
WP2 - Learned responses of parasitoids to infochemical evolutionary traps in a climate change context;
WP3 - Contest behaviour of local egg parasitoids for possession of co-evolved and non-coevolved hosts
WP4 - Patch time allocation of local egg parasitoids after alien herbivore invasion: behavioural and modelling approaches
WP5 - Use of molecular tools to define novel tritrophic interactions after alien herbivore invasion
WP6 - Genetic structure of invasive alien herbivores across Europe and North America

To date, research activities were conducted at the Entomology laboratory of Department of Agricultural, Food and Forest Sciences of University of Palermo, in the Department of Agricultural, Food and Environmental Sciences of the University of Perugia, at the laboratory of Department of Entomology and Agricultural Zoology of the Benaki Phytopathological Institute in Athens, at the laboratory of INRA - Sophia Antipolis, and in the laboratory of the Institut de Recherche en Biologie Végétale of University of Montreal. The activity involving the other research units of the Consortium are planned to be carried out during the second half of the project.
The main results achieved can be summarised as follow: 1) demonstration of H. halys ability to impact the plant volatile-mediated signalling in local tritrophic webs (both in Europe and North America) by interfering with indirect plant defence induced in response to local pentatomid feeding and oviposition activities (WP1); 2) demonstration that local egg parasitoids are not able to discriminate the invasive and not-associated host sex by exploiting host chemical footprints; however, this response is partially modified by a rewarded experience (WP2); 3) development of a protocol to quantify the intra-population polygenic genetic variation on behavioural traits involved in foraging decisions of egg parasitoids (WP4); demonstration that local egg parasitoids species are able to parasitize egg masses of H. halys, and that plants can recognize H. halys oviposition as a warning signal. This leads to pre-activation of plant defences against future nymphal herbivory and recruitment of local egg parasitoids (WP5); investigation of genetic diversity of H. halys populations from different geographical areas in Europe and North America (WP6).
The outcomes of the project will be relevant for improvement of the research and innovation potential of the collaborating teams in terms of both fundamental and applied ecology. In the short term, progress in fundamental research is expected by characterizing the ecological consequences of an alien herbivore invasion in a multi-trophic perspective.
In the long term this project can potentially generate environmental, agricultural and socio-economic impacts by applying invasive ecology concepts to reduce pesticide inputs in integrated pest management. In particular several work packages are focused on behavioral and chemical ecology of egg parasitoids (which are the main biological control agent of stink bugs) and manipulation of infochemicals to improve their efficiency in biological pest control is a promising strategy to minimize pesticide use in agriculture.
An important part of the INVASION project has already been devoted to result dissemination and networking.
The project has already strengthened the networking activities between European and Canadian researchers and long lasting collaborations have been established. Members of the Consortium have attended several key international conferences (including one held in Japan), and have visited international research institutes where results of the project were disseminated. In addition a detailed website has been developed which contains recent project updates (including meetings, reports and publications).
Figure 2 - INVASION overview of the tritrophic systems
Figure 1 - INVASION overview of the planned work packages