Search results for "Systematics"

The next meeting for animal personality: population genetics.

2015

8 pages; International audience

Age, pathogen exposure, but not maternal care shape offspring immunity in an insect with facultative family life

2017

International audience; Background: To optimize their resistance against pathogen infection, individuals are expected to find the right balance between investing into the immune system and other life history traits. In vertebrates, several factors were shown to critically affect the direction of this balance, such as the developmental stage of an individual, its current risk of infection and/or its access to external help such as parental care. However, the independent and/or interactive effects of these factors on immunity remain poorly studied in insects.Results: Here, we manipulated maternal presence and pathogen exposure in families of the European earwig Forficula auricularia to measur…

Modification of hosts' behavior by a parasite: field evidence for adaptive manipulation.

2007

9 pages; International audience; Parasites relying on trophic transmission to complete their life cycles often induce modifications of their host's behavior in ways that may increase their susceptibility to predation by final hosts. These modifications have often been interpreted as parasite adaptations, but very few studies have demonstrated that host manipulation has fitness benefits for the parasite. The aim of the present study was to address the adaptive significance of parasite manipulation by coupling observations of behavioral manipulation to estimates of trophic transmission to the definitive host in the natural environment. We show that the acanthocephalan parasite Pomphorhynchus …

Microsporidian disease of the invasive amphipod Dikerogammarus villosus and the potential for its transfer to local invertebrate fauna.

2012

12 pages; International audience; Invasive species may introduce novel pathogens to a colonised area. Most of the time emerging pathogens are detected a posteriori, but recognition of a priori emergence of an invasive disease by host shift may be useful for predictive purposes. Here, we studied if the microsporidian parasite Cucumispora dikerogammari infecting the invasive Ponto-Caspian amphipod Dikerogammarus villosus, has the potential to become an emergent disease in invaded rivers in Western and Central Europe. We first showed that this parasite decreases the survival of D. villosus in the later stages of infection development. However, the host reproduces earlier in response to the inf…

Une chrysomèle contre l'ambroisie, est-ce réaliste ?

2016

Context - Despite intensive management practices carried out by stakeholders, common ragweed control is presently not sufficient to limit the spread of this annual invasive plant. Ali classical methods (mowing, chemical weeding, etc.) are limited in terms of efficiency. ln order to achieve a better management in the different habitats occupied by the plant, it is necessary to design innovative methods that could increase contra efficiency. The recent accidental introduction of a ragweed natural enemy in ltalia raises the question of the use of biological control agents. Could the regulation by a new phytophagous insect be considered as an integrated way of management in order to reduce the …

Permineralized coniferophytes from the Autun Basin: specimens from two new localities of Renault zone 3

2015

International audience; Four zones yielding silicified plant remains have been recognized in the Autun Basin by Renault (1893-1896). Zones 2, 3 and 4, characterized by Autunian plants, correspond to the successive formations of Igornay and Muse (lower Autunian), and Surmoulin-Millery (upper Autunian). Their paleobotanical content, together with that preserved as adpressions in the same formations, document paleofloral changes on the western side of the Tethys within a time interval extending from the latest Ghzelian (uppermost Pennsylvanian) to the early Sakmarian (lower Permian) (Broutin et al. 1999). The analyses realized so far indicate a progressive replacement of wetland plants by taxa…

La lutte biologique contre l'ambroisie à feuille d'armoise illustrée par l'exemple d'Ophraella communa : quels intérêts et quelles limites

2016

Common ragweed (Ambrosia artemisiifolia) was introduced in France over 150 years ago and its spreading across France now seems inexorable. The specific biology of this summer annual creates new problems for the managers of the various habitats where the plant can be found. The reduced possibility, or even the impossibility, to use traditional control means in certain environment conditions brings managers to consider biological control as one of the few possible means for slowing down the spread, or even pushing back the distribution area, of this invasive and allergenic plant. With Ophraella communa as an example, a reflection is presented on the benefit-risk balance of the introduction of…

Biodiversity and taxonomy in primates: between extinction and inflation.

2020

Growth response of the saltbush Atriplex nummularia L. to inoculation with the arbuscular mycorrhizal fungus Glomus intraradices

2005

Abstract Plantlets of Atriplex nummularia were inoculated with the arbuscular mycorrhizal fungi Glomus intraradices in a pot experiment. Plants were grown in a low P soil. Highly significant growth response of a Chenopodiaceae was recorded for the first time. Mycorrhizal colonization of roots was well developed, internal hyphae and vesicles were observed, but not arbuscules. These observations suggest that arbuscules are not necessary to obtain significant growth stimulation from mycorrhizal inoculation. Atriplex nummularia is already used as forage crops, its high mycorrhizal dependency offers possibilities to develop this production and revegetation strategies.

Depth matters : Effects of precipitation regime on soil microbial activity upon rewetting of a plant-soil system

2018

International audience; Climate change is predicted to affect not only the amount but also the temporal distribution of rain. Changes in frequency and amplitude of rain events, i.e. precipitation patterns, result in different water conditions with soil depth, and likely affect plant growth and shape plant and soil microbial activity. Here, we used 18O stable isotope probing (SIP) to investigate bacterial and fungal communities that actively grew or not upon rewetting, at three different depths in plant-soil mesocosms previously subjected to frequent or infrequent watering for 12 weeks (equal total water input). Phylogenetic marker genes for bacteria and fungi were sequenced after rewetting,…