Search results for "Fitness cost"
showing 7 items of 7 documents
Ants medicate to fight disease
2015
Parasites are ubiquitous, and the ability to defend against these is of paramount importance. One way to fight diseases is self-medication, which occurs when an organism consumes biologically active compounds to clear, inhibit, or alleviate disease symptoms. Here, we show for the first time that ants selectively consume harmful substances (reactive oxygen species, ROS) upon exposure to a fungal pathogen, yet avoid these in the absence of infection. This increased intake of ROS, while harmful to healthy ants, leads to higher survival of exposed ants. The fact that ingestion of this substance carries a fitness cost in the absence of pathogens rules out compensatory diet choice as the mechanis…
Survival cost of an early immune soliciting in nature.
2009
8 pages; International audience; If immune functions confer obvious benefits to hosts, life-history theory assumes that they also induce costs, leading to trade-offs between immunity and other fitness components. However, whether substantial fitness costs are associated with immune systems in the wild is debatable, as numerous factors may influence the costs and benefits associated with immune activation. Here, we explore the survival cost of immune deployment in postfledging birds. We injected Eurasian collared dove nestlings (Streptopelia decaocto) with antigens from Escherichia coli, and examined whether this immune challenge affected survival after fledging. To assess survival, birds we…
Trans-generational immune priming in the mealworm beetle protects eggs through pathogen-dependent mechanisms imposing no immediate fitness cost for t…
2018
8 pages; International audience; Immune-challenged mothers can improve their offspring immunity through trans-generational immune priming (TGIP). In insects, TGIP endows the offspring with lifetime immunity, including the eggs, which are likely exposed soon after maternal infection. Egg protection may rely on the transfer of maternal immune effectors to the egg or/and the induction of egg immune genes. These respective mechanisms are assumed to have early-life fitness costs of different magnitude for the offspring. We provide evidence in the mealworm beetle Tenebrio molitor that enhanced egg immunity following a maternal immune challenge is achieved by both of these mechanisms but in a path…
Fitness costs of increased cataract frequency and cumulative radiation dose in natural mammalian populations from Chernobyl
2015
AbstractA cataract is a clouding of the lens that reduces light transmission to the retina and it decreases the visual acuity of the bearer. The prevalence of cataracts in natural populations of mammals and their potential ecological significance, is poorly known. Cataracts have been reported to arise from high levels of oxidative stress and a major cause of oxidative stress is ionizing radiation. We investigated whether elevated frequencies of cataracts are found in eyes of bank voles Myodes glareolus collected from natural populations in areas with varying levels of background radiation in Chernobyl. We found high frequencies of cataracts in voles collected from different areas in Chernob…
Mode of selection and experimental evolution of antiviral drugs resistance in vesicular stomatitis virus
2004
Abstract The possession of an antiviral resistance mutation benefits a virus when the corresponding antiviral is present. But does the resistant virus pay a fitness cost when the antiviral is absent? Would an evolutionary history of association between a genotype and a resistance mutation overcome this cost by changes compensating the harmful side-effect of resistance mutations? Are combined therapies more effective against the rise of resistant viruses or against evolutionary compensations? To explore all these questions, we took an experimental evolution approach. After selecting vesicular stomatitis virus (VSV) populations able to replicate under increasing concentrations of ribavirin an…
Mutant ACCase alleles endowing herbicide resistance have a direct effect on seed germination
2013
Germination and emergence dynamics and herbicide resistance are adaptive traits crucial for weed persistence in arable fields. Herbicide resistance alleles can have pleiotropic effects on other traits. We investigated the pleiotropic effects of acetyl-coenzyme A carboxylase (ACCase) alleles L1781, N2041 or G2078 on seed germination and seedling emergence in the grass weed Alopecurus myosuroides (black-grass). We used black-grass populations with homogenised genetic backgrounds that segregated for L1781, N2041 or G2078 ACCase alleles. In two series of experiments, germination dynamics and seedling growth were compared among seeds containing embryos carrying no, one or two copies of a given m…
Adapting cropping system to delay herbicide resistance. A simulation study
2014
Weeds have evolved resistance to numerous herbicides, and their management becomes increasingly expensive and difficult. Here we (1) adapted the existing weed dynamics simulation model AlomSys to account for target-site resistance to acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides in Alopecurus myosuroides by integrating wild and mutant target-site resistant (TSR) genotypes, mutations, fitness costs and seed immigration, and (2) ran simulations testing different crop management practices for their ability to delay resistance evolution and/or control of TSR plants. Simulations of an oilseed rape/winter wheat/winter barley rotation showed that TSR plants exceeded 1 plant/m² appro…