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The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations.

Belinato TA, Valle D - PLoS ONE (2015)

Bottom Line: Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides.Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost.We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro (RJ), Brasil.

ABSTRACT
Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

No MeSH data available.


Related in: MedlinePlus

Rate of bloodmeal acceptance for females from the Rockefeller strain (Rock), selected (dfb), or control (cont) groups from Boa Vista (BVT) and Aparecida de Goiânia (APG).Different letters above the columns indicate significant differences among groups (χ2; P < 0.05).
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pone.0130719.g006: Rate of bloodmeal acceptance for females from the Rockefeller strain (Rock), selected (dfb), or control (cont) groups from Boa Vista (BVT) and Aparecida de Goiânia (APG).Different letters above the columns indicate significant differences among groups (χ2; P < 0.05).

Mentions: Approximately 96% (87/90) of the Rockefeller specimens and a similar proportion of BVT control females (95%, 173/181) took a blood meal (χ20.05,1 = 0,1822; P = 0.3347). In contrast, APG control females were less efficient feeders in comparison to the Rockefeller strain (84%, 152/180) (χ20.05,1 = 13,57; P = 0.0001) (Fig 6). Selection with DFB reduced the ability of both populations to successfully obtain a blood meal. Only 62% (168/275) of BVT and 49% (146/270) of APG DFB-selected females ingested blood, and these rates were significantly lower than those observed for the Rockefeller strain (BVT: χ20.05,1 = 40,76; p < 0.0001; APG: χ20.05,1 = 64,67; P < 0.0001). For each population, comparison between the control and insecticide-treated groups also shows that selection with DFB significantly impaired blood feeding success (BVT: χ20.05,1 = 68,85; p < 0.0001; APG: χ20.05,1 = 45,70; P < 0.0001). Similarly, there was a significant difference in feeding success between the DFB-selected groups of the two Brazilian populations (χ20.05,1 = 8,19; P = 0.0021).


The Impact of Selection with Diflubenzuron, a Chitin Synthesis Inhibitor, on the Fitness of Two Brazilian Aedes aegypti Field Populations.

Belinato TA, Valle D - PLoS ONE (2015)

Rate of bloodmeal acceptance for females from the Rockefeller strain (Rock), selected (dfb), or control (cont) groups from Boa Vista (BVT) and Aparecida de Goiânia (APG).Different letters above the columns indicate significant differences among groups (χ2; P < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481264&req=5

pone.0130719.g006: Rate of bloodmeal acceptance for females from the Rockefeller strain (Rock), selected (dfb), or control (cont) groups from Boa Vista (BVT) and Aparecida de Goiânia (APG).Different letters above the columns indicate significant differences among groups (χ2; P < 0.05).
Mentions: Approximately 96% (87/90) of the Rockefeller specimens and a similar proportion of BVT control females (95%, 173/181) took a blood meal (χ20.05,1 = 0,1822; P = 0.3347). In contrast, APG control females were less efficient feeders in comparison to the Rockefeller strain (84%, 152/180) (χ20.05,1 = 13,57; P = 0.0001) (Fig 6). Selection with DFB reduced the ability of both populations to successfully obtain a blood meal. Only 62% (168/275) of BVT and 49% (146/270) of APG DFB-selected females ingested blood, and these rates were significantly lower than those observed for the Rockefeller strain (BVT: χ20.05,1 = 40,76; p < 0.0001; APG: χ20.05,1 = 64,67; P < 0.0001). For each population, comparison between the control and insecticide-treated groups also shows that selection with DFB significantly impaired blood feeding success (BVT: χ20.05,1 = 68,85; p < 0.0001; APG: χ20.05,1 = 45,70; P < 0.0001). Similarly, there was a significant difference in feeding success between the DFB-selected groups of the two Brazilian populations (χ20.05,1 = 8,19; P = 0.0021).

Bottom Line: Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides.Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost.We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro (RJ), Brasil.

ABSTRACT
Several Aedes aegypti field populations are resistant to neurotoxic insecticides, mainly organophoshates and pyrethroids, which are extensively used as larvicides and adulticides, respectively. Diflubenzuron (DFB), a chitin synthesis inhibitor (CSI), was recently approved for use in drinking water, and is presently employed in Brazil for Ae. aegypti control, against populations resistant to the organophosphate temephos. However, tests of DFB efficacy against field Ae. aegypti populations are lacking. In addition, information regarding the dynamics of CSI resistance, and characterization of any potential fitness effects that may arise in conjunction with resistance are essential for new Ae. aegypti control strategies. Here, the efficacy of DFB was evaluated for two Brazilian Ae. aegypti populations known to be resistant to both temephos and the pyrethroid deltamethrin. Laboratory selection for DFB resistance was then performed over six or seven generations, using a fixed dose of insecticide that inhibited 80% of adult emergence in the first generation. The selection process was stopped when adult emergence in the diflubenzuron-treated groups was equivalent to that of the control groups, kept without insecticide. Diflubenzuron was effective against the two Ae. aegypti field populations evaluated, regardless of their resistance level to neurotoxic insecticides. However, only a few generations of DFB selection were sufficient to change the susceptible status of both populations to this compound. Several aspects of mosquito biology were affected in both selected populations, indicating that diflubenzuron resistance acquisition is associated with a fitness cost. We believe that these results can significantly contribute to the design of control strategies involving the use of insect growth regulators.

No MeSH data available.


Related in: MedlinePlus