Search results for "muta"
showing 10 items of 6895 documents
Insecticide residues in cotton soils of Burkina Faso and effects of insecticides on fluctuating asymmetry in honey bees (Apis mellifera Linnaeus).
2011
8 pages; International audience; Four insecticides (acetamiprid, cypermethrin, endosulfan and profenofos) are used quarterly in the cotton-growing areas of Burkina Faso, West Africa. These insecticides were investigated in soils collected from traditionally cultivated and new cotton areas. Also, the effects of insecticide exposure on the developmental instability of honey bees, Apis mellifera, were explored. In soil samples collected three months after insecticide treatments, endosulfan and profenofos concentrations varied in the range of 10-30μgkg(-1) in the traditionally cultivated zones and 10-80μgkg(-1) in the new cotton zones, indicating a pollution of agricultural lands. However, only…
Mutations associated with pyrethroid resistance in Varroa mite, a parasite of honey bees, are widespread across the United States.
2021
BACKGROUND Managed honey bees are key pollinators of many crops and play an essential role in the United States food production. For more than ten years, beekeepers in the United States have been reporting high rates of colony losses. One of the drivers of these losses is the parasitic mite Varroa destructor. Maintaining healthy honey bee colonies in the United States is dependent on a successful control of this mite. The pyrethroid tau-fluvalinate (Apistan®) was among the first synthetic varroacides registered in the United States. With over 20 years of use, mites resistant to Apistan® have emerged, and so it is unsurprising that treatment failures have been reported. Resistance to tau-flu…
Diversifying selection on MHC class I in the house sparrow (Passer domesticus).
2009
10 pages; International audience; Genes of the major histocompatibility complex (MHC) are the most polymorphic loci known in vertebrates. Two main hypotheses have been put forward to explain the maintenance of MHC diversity: pathogen-mediated selection and MHC-based mate choice. Host-parasite interactions can maintain MHC diversity via frequency-dependent selection, heterozygote advantage, and diversifying selection (spatially and/or temporally heterogeneous selection). In this study, we wished to investigate the nature of selection acting on the MHC class I across spatially structured populations of house sparrows (Passer domesticus) in France. To infer the nature of the selection, we comp…
Reverse-engineering the Arabidopsis thaliana transcriptional network under changing environmental conditions
2009
46 pages, 4 tables, 6 figures, 3 additinoal files.
Spatial monitoring of gene activity in extraradical and intraradical developmental stages of arbuscular mycorrhizal fungi by direct fluorescent in si…
2008
International audience; Gene expression profiling based on tissue extracts gives only limited information about genes associated with complex developmental processes such as those implicated in fungal interactions with plant roots during arbuscular mycorrhiza development and function. To overcome this drawback, a direct fluorescent in situ RT-PCR methodology was developed for spatial mapping of gene expression in different presymbiotic and symbiotic structures of an arbuscular mycorrhizal fungus. Transcript detection was optimized by targeting the LSU rRNA gene of Glomus intraradices and monitoring expression of a stearoyl-CoA-desaturase gene that is consistently expressed at high levels in…
Investigation of deltamethrin resistance in salmon lice (Lepeophtheirus salmonis) provides no evidence for roles of mutations in voltage-gated sodium…
2020
BACKGROUND The pyrethroid deltamethrin is used to treat infestations of farmed salmon by parasitic salmon lice, Lepeophtheirus salmonis (Kroyer). However, the efficacy of deltamethrin for salmon delousing is threatened by resistance development. In terrestrial arthropods, knockdown resistance (kdr) mutations of the voltage-gated sodium channel (Nav ), the molecular target for pyrethroids, can cause deltamethrin resistance. A putative kdr mutation of an L. salmonis sodium channel homologue (LsNav 1.3 I936V) has been identified previously. At the same time, deltamethrin resistance of L. salmonis has been shown to be inherited maternally and to be associated with mitochondrial DNA (mtDNA) muta…
Advantage of rare infanticide strategies in an invasion experiment of behavioural polymorphism
2012
Killing conspecific infants (infanticide) is among the most puzzling phenomena in nature. Stable polymorphism in such behaviour could be maintained by negative frequency-dependent selection (benefit of rare types). However, it is currently unknown whether there is genetic polymorphism in infanticidal behaviour or whether infanticide may have any fitness advantages when rare. Here we show genetic polymorphism in non-parental infanticide. Our novel invasion experiment confirms negative frequency-dependent selection in wild bank vole populations, where resource benefits allow an infanticidal strategy to invade a population of non-infanticidal individuals. The results show that infanticidal beh…
Does evolution of iteroparous and semelparous reproduction call for spatially structured systems?
2000
A persistent question in the evolution of life histories is the fitness trade-off between reproducing only once (semelparity) in a lifetime or reproducing repeated times in different seasons (iteroparity). The problem can be formulated into a research agenda by assuming that one reproductive strategy is resident (has already evolved) and by asking whether invasion (evolution) of an alternative reproductive strategy is possible. For a spatially nonstructured system, Bulmer (1994) derived the relationship v + PA1 (PA is adult survival; vbS and bS are offspring numbers for iteroparous and semelparous breeding strategies, respectively) at which semelparous population cannot be invaded by an ite…
Effect of gender on physiological and behavioural responses of Gammarus roeseli (Crustacea Amphipoda) to salinity and temperature.
2010
8 pages; International audience; The importance of potentially interacting factors in organisms responses to a stress are often ignored or underestimated in ecotoxicology. In laboratory experiments we investigated how gender, temperature and age influence the behaviour and the physiology of the freshwater amphipod Gammarus roeseli under salinity stress. Our results revealed a significant higher sensitivity of females in survival, ventilation and ionoregulation whereas no inter-age differences were reported. Water temperature also exerted a significant effect in survival and ventilation of G. roeseli. Some of those factors appeared to interact significantly. This study provides evidence that…
First Assessment of Plasticizers in Marine Coastal Litter-Feeder Fauna in the Mediterranean Sea
2021
Micro and nanoplastics are harmful to marine life due to their high level of fragmentation and resistance to degradation. Over the past two decades, marine coastal sediment has shown an increasing amount of microplastics being a sort of trap for debris wastes or chemicals. In such an environment some species may be successful candidates to be used as monitors of environmental and health hazards and can be considered a mirror of threats of natural habitats. Such species play a key role in the food web of littoral systems since they are litter-feeders, and are prey for fishes or higher trophic level species. A preliminary investigation was conducted on five species of small-sized amphipod cru…