2016-2017 institutional highlights
– INRA, SPE department
• Drosophila suzukii triggers grape acid decay •
The implication of Drosophila suzukii in the acid decay epidemic that struck vineyards in 2014 is suspected, but questioned by certain observations in the field. By combining field analyses and laboratory experiments, we show that D. suzukii can cause the disease. Furthermore, there is a synergy between D. suzukii et D. melanogaster: The first one triggers the disease whereas the second is attracted, takes advantage of the fruit wound to lay and amplify the disease.
Involved PhD: Antoine Rombaut
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• Arthropods: estimating the risks of bioinvasion •
Bioinvasions are considered the second cause of species extinction and loss of biodiversity after the destruction of natural habitat. Among invasive species, arthropod pests inflict enormous financial damage and are a threat to forests, agriculture and the health of humans and animals alike. To improve how arthropod invasion risks are estimated, Martin Godefroid is conducting a PhD at CBGP, entitled (“Estimating the risk of invasion by arthropod quarantine pests and the role of climate, evolutionary history and life history traits”. The research is supervised by Jean-Pierre Rossi and Jean-Yves Rasplus and financed by the Sustainable Management of Crop Health (SMaCH) metaprogram.
• A behaviour change in harvest techniques appeared repeatedly in European and Asian corn borers •
Little before harvest, caterpillars of borers O. nubilalis (in Europe) and O. furnacalis (in Asia) come down towards the collar of the maize canes, cross under the reaping line during harvest and avoid a quasi-certain death. This positive geotaxis behaviour – that is absent in their twin species O. scapulalis, which does not attack maize, certainly corresponds to a harvest behaviour change (especially with combine harvesters), which would have repeatedly appeared in the two species.
Vincent Calcagno (unité ISA)
– INRA, EFPA department
• Who eats what: metabarcoding applied to bats and their prey •
Chiroptera play a major ecological role but they are among the most threatened species in Europe. Together with LBBE (Biometry and Evolutionary Biology laboratory) in Lyons, with the Chrono-environment laboratory in Besançon and the Poitou-Charentes Nature array, we conduct a research project to study the causes of these populations' decline. We finalized a high-speed sequencing approach allowing the gene and parallel identification, from their faeces, of the host bat species and their prey arthropod species.
• Pangenomic data to redraw a major change in phenology in the pine processionary moth •
The pine processionary moth, Thaumetopoea pityocampa, is an urticating Mediterranean defoliator insect that causes animal and human health issues in the whole Mediterranean region. A population with a shifted phenology, that is urticating in summer but not in winter, has been co-studied by CBGP and the University of Lisbon for a dozen years. Processing population genomic tools allowed to redraw precisely this spectacular differentiation, which raised approximately 500 years ago.
• When do desert locusts become gregarious? •
Desert locusts, which are usually solitary and inoffensive, can very rapidly become gregarious and form gigantic swarms that devastate vegetation. What are the mechanisms behind this and what factors trigger it? Along with the FAO Commission for Controlling the Desert Locust in the Western Region and several other organizations in North and West Africa, CIRAD has undertaken research to pinpoint the environmental conditions and insect densities that lead desert locusts to become gregarious. The aim is to anticipate and manage attacks by this pest more efficiently.
• Desert locusts: new risks in the light of climate change •
The desert locust is an invasive species that is both well known and feared because of the large-scale agricultural damage it can cause. It is particularly closely monitored, to prevent the risks of outbreaks and invasions. Climate change could modify its distribution area, meaning a new threat to agriculture, according to a study published in the journal Global Change Biology by researchers from CIRAD and INRA.
• Leptospirosis first detection in Niger •
Leptospirosis is a zoonosis mainly transmitted by water contaminated by the urine of infected mammals. It was rarely studied in arid regions as the Sahel. For the first time, a team of IRD, assisted by academic and institutional partners, gave evidence of the presence of rodents affected by Leptospira pathogenic bacteria in the city of Niamey, thanks to gene analyses.
« All affected rodents belong to species living in market gardens along the river Niger and its tributaries. But in Niamey, species found in houses are not infected, although they can carry Leptospira in other regions of the world. The bacteria only spread in the urban farming community », says Gauthier Dobigny.
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• Leptospirosis, a forgotten zoonosis •
Leptospirosis is a major public health issue in the South. Each year it affects at least one million people and takes 60 000 lives. Yet, leptospirosis remains little-known, badly handled by care staff, under-documented and undervalued by health authorities. It does not appear in the list of ignored tropical diseases. Its ecology evolves with urbanization and it could even progress with the climate change. Scientists from IRD and partners are studying that emerging and neglected disease...
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• "The black rat, an invader dependent on transport" and "A very invasive mouse" in Senegal •
Researches on Rattus rattus in Senegal, an invasive mouse, reveal unexpected aspects of population dynamics. Geoclimatic constraints and competition of other commensal rodents handicap its expansion... And another man's commensal rodent, the house mouse Mus musculus, is expanding since the time of the colonial trading posts...
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