Costly resistance mechanisms have been cited as an explanation for the widespread occurrence of @entity281 , yet few studies have examined these costs in detail. A @entity311 -mosquito model has been used to test this concept by making a comparison of the fitness of highly susceptible lines of mosquitoes with lines that are resistant to @entity281 . @entity281 is known to cause a decrease in fecundity and fertility of mosquitoes; resistant mosquitoes were thus predicted to be fitter than susceptible ones. @entity313 were selected for refractoriness/resistance or for increased susceptibility to @entity281 by @entity501 nigeriensis. Additional lines that acted as controls for inbreeding @entity308 were raised in parallel but not exposed to selection pressure. Selections were made in triplicate so that founder effects could be detected. Resistance mechanisms that were selected included melanotic encapsulation of @entity4801 within 24 h postinfection and the complete disappearance of @entity4801 from the gut. Costs of immune surveillance were assessed after an uninfected feed, and costs of immune deployment were assessed after exposure to @entity281 and to @entity281 and additional stresses. Mosquito survivorship was unaffected by either resistance to @entity281 or by an increased burden of @entity281 when compared with low levels of @entity281 . In most cases reproductive fitness was equally affected by refractoriness or by @entity281 . Resistant mosquitoes did not gain a fitness advantage by eliminating the @entity4801 . Costs were consistently associated with larval production and egg hatch rate but rarely attributed to changes in blood feeding and never to changes in mosquito size. No advantages appeared to be gained by the offspring of resistant mosquitoes. Furthermore, we were unable to select for refractoriness in groups of mosquitoes in which 100% or 50% of the population were exposed to @entity281 every generation for 22 generations. Under these selection pressures, no population had become completely refractory and only one became more resistant. Variations in fitness relative to control lines in different groups were attributed to founder effects. Our conclusion from these findings is that refractoriness to @entity311 is as costly as tolerance of @entity281 .

Evaluating the costs of mosquito resistance to XXXX @entity4801 .

@entity308 :: ('MESH:D003866', 'Disease') :: ['depression'] @entity281 :: ('MESH:D007239', 'Disease') :: ['infection', 'parasitic infections', 'Malaria infection'] @entity501 :: ('5861', 'Species') :: ['Plasmodium yoelii'] @entity4801 :: ('MESH:D010272', 'Disease') :: ['parasites'] @entity311 :: ('MESH:D008288', 'Disease') :: ['malaria'] @entity313 :: ('7165', 'Species') :: ['Anopheles gambiae']
@entity311 :: (MESH:D008288,Disease) :: ['malaria']
