title: Fitness cost in field and laboratory Aedes aegypti populations associated with resistance to the insecticide temephos.
abstract: BACKGROUND
  The continued use of chemical insecticides in the context of the National Program of Dengue Control in Brazil has generated a high selective pressure on the natural populations of Aedes aegypti, leading to their resistance to these compounds in the field. Fitness costs have been described as adaptive consequences of resistance. This study evaluated the biological and reproductive performance of A. aegypti strains and a field population resistant to temephos, the main larvicide used for controlling mosquitoes.
  
  
  METHODS
  Comparative tests were performed with a resistant field population from the municipality of Arcoverde, Pernambuco State, Brazil, with a high rate of temephos resistance (RR = 226.6) and three isogenetic laboratory strains from the same origin (Araripina municipality, Pernambuco): RecR (RR = 283.6); RecRNEx (RR = 250.5), a strain under a process of resistance reversion; and RecRev (RR = 2.32), a reversed susceptible strain used as an experimental control.
  
  
  RESULTS
  Our study revealed that the absence of selective pressure imposed by exposure to temephos, for five consecutive generations, led to a discrete reduction of the resistance ratio and the response of the detoxifying enzymes. Most of the 19 biological parameters were impaired in the resistant strains and field population. The analysis of the fertility life table confirmed the presence of reproductive disadvantages for the resistant individuals. Similarly, the longevity, body size, and total energetic resources were also lower for the resistant females, except for the last two parameters in the field females (Arcoverde). In contrast, the sex ratio and embryonic viability suffered no interference in all strains or population evaluated, regardless of their status of resistance to temephos.
  
  
  CONCLUSIONS
  The reproductive potential and survival of the resistant individuals were compromised. The parameters most affected were the larval development time, fecundity, net reproduction rate, and the generational doubling time. These fitness costs in the natural population and laboratory strains investigated are likely associated with maintaining the metabolic mechanism of resistance to temephos. Our results show that despite these costs, the highly temephos resistant populations can compensate for these losses and successfully overcome the control actions that are based on the use of chemical insecticides.
authors.affiliation: Department of Entomology, Aggeu Magalhães Research Center (Centro de Pesquisas Aggeu Magalhães - CPqAM) - Oswaldo Cruz Foundation (Fundação Oswaldo Cruz - Fiocruz), Recife, Brazil. didiegofelipe@gmail.com.
authors.forename: Diego Felipe Araujo
authors.initials: DF
authors.lastname: Diniz
authors.affiliation: Department of Entomology, Aggeu Magalhães Research Center (Centro de Pesquisas Aggeu Magalhães - CPqAM) - Oswaldo Cruz Foundation (Fundação Oswaldo Cruz - Fiocruz), Recife, Brazil. mavarjal@cpqam.fiocruz.br.
authors.forename: Maria Alice Varjal
authors.initials: MA
authors.lastname: de Melo-Santos
authors.affiliation: Department of Entomology, Aggeu Magalhães Research Center (Centro de Pesquisas Aggeu Magalhães - CPqAM) - Oswaldo Cruz Foundation (Fundação Oswaldo Cruz - Fiocruz), Recife, Brazil. eloina.santos@gmail.com.
authors.forename: Eloína Maria de Mendonça
authors.initials: EM
authors.lastname: Santos
authors.affiliation: Department of Biology, State University of Paraíba (Universidade Estadual da Paraíba - UEPB), Campina Grande, Brazil. ebarbosa@uepb.edu.br.
authors.forename: Eduardo Barbosa
authors.initials: EB
authors.lastname: Beserra
authors.affiliation: Department of Entomology, Aggeu Magalhães Research Center (Centro de Pesquisas Aggeu Magalhães - CPqAM) - Oswaldo Cruz Foundation (Fundação Oswaldo Cruz - Fiocruz), Recife, Brazil. elisama_helvecio@hotmail.com.
authors.forename: Elisama
authors.initials: E
authors.lastname: Helvecio
authors.affiliation: Department of Entomology, Aggeu Magalhães Research Center (Centro de Pesquisas Aggeu Magalhães - CPqAM) - Oswaldo Cruz Foundation (Fundação Oswaldo Cruz - Fiocruz), Recife, Brazil. danilo@cpqam.fiocruz.br.
authors.forename: Danilo
authors.initials: D
authors.lastname: de Carvalho-Leandro
authors.affiliation: Laboratory of Lipids, Biochemistry Department, Federal University of Pernambuco (Universidade Federal de Pernambuco - UFPE), Recife, Brazil. biankasantana@hotmail.com.
authors.forename: Bianka Santana
authors.initials: BS
authors.lastname: dos Santos
authors.affiliation: Laboratory of Lipids, Biochemistry Department, Federal University of Pernambuco (Universidade Federal de Pernambuco - UFPE), Recife, Brazil. vlml@ufpe.br.
authors.forename: Vera Lúcia
authors.initials: VL
authors.lastname: de Menezes Lima
authors.affiliation: Department of Entomology, Aggeu Magalhães Research Center (Centro de Pesquisas Aggeu Magalhães - CPqAM) - Oswaldo Cruz Foundation (Fundação Oswaldo Cruz - Fiocruz), Recife, Brazil. tans@cpqam.fiocruz.br.
authors.forename: Constância Flávia Junqueira
authors.initials: CF
authors.lastname: Ayres
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000502:physiology*; D000818:Animals; D049628:Body Size; D001938:Brazil; D005298:Fertility; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D008136:Longevity; D012098:Reproduction; D012641:Selection, Genetic; D016019:Survival Analysis; D000002:Temefos / Q000494:pharmacology*
chemical_list: D007306:Insecticides; D000002:Temefos