Search results for "IOS"

Rapid induction of immune density-dependent prophylaxis in adult social insects.

2009

The innate immune system provides defence against parasites and pathogens. This defence comes at a cost, suggesting that immune function should exhibit plasticity in response to variation in environmental threats. Density-dependent prophylaxis (DDP) has been demonstrated mostly in phase-polyphenic insects, where larval group size determines levels of immune function in either adults or later larval instars. Social insects exhibit extreme sociality, but DDP has been suggested to be absent from these ecologically dominant taxa. Here we show that adult bumble-bee workers ( Bombus terrestris ) exhibit rapid plasticity in their immune function in response to social context. These results sugges…

Climate Change: Negationism, Skepticism, and Misinformation

2021

Resumen: El objetivo de este artículo es examinar los principales lineamientos antagonistas sobre el cambio climático. Para ello, se ofrece una aproximación teórica a las narrativas y repertorios sustantivos que sostienen los fundamentos de la negación y se diferencia conceptualmente entre negacionistas, climatoescépticos y contrarios climáticos. Estos repertorios son la negación de las evidencias científicas, la negación económica y la negación política. Finalmente, se hace referencia a la difusión de información errónea y tóxica como estrategia organizada y deliberada. Como principal conclusión se abordan los emergentes programas de alfabetización climática para neutralizar la desinformac…

Effects of Acifluorfen-methyl on cucumber cotyledons : porphyrin accumulation

1988

Abstract The nitrodiphenyl ether herbicide acifluorfen-methyl and the pyridine derivative LS 82-556 induce porphyrin accumulation in green cucumber cotyledons. When experiments are done with intact plants absorbing the herbicide through the roots, that accumulation is light-dependent. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) which prevents cellular damages under these conditions (M. Matringe and R. Scalla, Pestic. Biochem. Physiol. 26 , 150 (1986), also inhibits porphyrin accumulation. In contrast, when detached cotyledons are cut into pieces and floated on herbicide solutions, porphyrins accumulate in the dark. Accordingly, DCMU does not inhibit porphyrin accumulation or protect the …

Iridescent structurally based coloration of eyespots correlates with mating success in the peacock.

2007

Gaudy plumage coloration is a widespread ornamental trait in birds and thought to be sexually selected. Although much attention has been devoted to structural coloration reflecting in UV, the signaling function of structural colors lacking UV reflectance and those that exhibit iridescence coloration are poorly documented. The train of the peacock (Pavo cristatus), a classical example of a sexually selected trait, is composed of iridescent structurally colored eyespots not reflecting in UV. Until today, the role played by the structural color of the eyespots in female mate choice has never been investigated using spectrometry. We measured eyespot coloration from a stationary angle (static co…

Discriminating uniparental and biparental breeding strategies by monitoring nest temperature

2017

10 pages; International audience; Birds exhibit a wide diversity of breeding strategies. During incubation or chick-rearing, parental care can be either uniparental, by either the male or the female, or biparental. Understanding the selective pressures that drive these different strategies represents an exciting challenge for ecologists. In this context, assigning the type of parental care at the nest (e.g. biparental or uniparental incubation strategy) is often a prerequisite to answering questions in evolutionary ecology. The aim of this study was to produce a standardized method unequivocally to assign an incubation strategy to any Sanderling Calidris alba nest found in the field by moni…

2017

Diversification in flower shape and function is triggered by the high plasticity of flower meristems. Minute changes in space and time can profoundly affect the formation of adult structures. Dipsacoideae provides an excellent model system to investigate the evolutionary aspects of temporal and spatial changes in flower development due to its small size, the resolved phylogenetic framework, and significant diversity of perianth form and merosity. In the present study, we investigated the sequence of floral organ initiation and quantified the interactions between flower meristem expansion and petal primordium size in eight species representing two major clades of Dipsacoideae. Our quantitati…

Physiological Performance of a Coastal Marsh Plant Hydrocotyle vulgaris in Natural Conditions in Relation to Mineral Nutrition and Mycorrhizal Symbio…

2020

Abstract Fluctuating soil salinity and competition for light are the main factors affecting plant distribution and performance in coastal salt marshes. The aim of the present study was to assess plant performance by means of non-destructive instrumental methods in a highly heterogeneous natural habitat. More specifically, environmental factors affecting growth and physiological performance of a clonal plant Hydrocotyle vulgaris L. were investigated. Changes in soil salinity, soil mineral characteristics, leaf nutrient concentrations, morphological parameters, chlorophyll fluorescence, and mycorrhizal symbiosis were analysed in different experimental plots of naturally growing H. vulgaris pl…

Attraction of Trichogramma Wasps to Butterfly Oviposition-Induced Plant Volatiles Depends on Brassica Species, Wasp Strain and Leaf Necrosis

2021

Within the Brassicaceae, wild as well as crop species are challenged by specialist herbivores including cabbage white butterflies (Pieris spp.). The wild crucifer Brassica nigra responds to oviposition by Pieris butterflies by the synergistic expression of two egg-killing traits. Genotypes that express a hypersensitive response (HR)-like necrosis (direct egg-killing) also emit oviposition-induced plant volatiles (OIPVs) attracting Trichogramma egg parasitoids (indirect egg-killing). This so-called double defense line can result in high butterfly egg mortalities. It remains unknown whether this strategy is unique to B. nigra or more common in Brassica species. To test this, we examined the r…

Effect of Multiple Parasitic Infections on the Tolerance to Pollutant Contamination

2012

8 pages; International audience; The horizontally-transmitted acanthocephalan parasite Polymorphus minutus and the vertically-transmitted microsporidian parasite Dictyocoela roeselum have both been shown to influence on the antitoxic responses of mono-infected Gammarus roeseli exposed to cadmium. The present study investigates the effect of this co-infection on the antitoxic defence responses of naturally infected females exposed to cadmium stress. Our results revealed that, depending on the cadmium dose, bi-infection induced only slight, significant increased cell damage in G. roeseli as compared to non-infection. In addition, the antitoxic defence pattern of cadmium-exposed bi-infected ho…

Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO2.

2012

10 pages; International audience; Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been devel…