48 research outputs found
Fitness advantages in multiple blood-feeding: the Aedes aegypti example
Only a few of the over three thousand species of mosquitoes in the world have evolved a close association with human settlements (i.e. domestic habits) and a subsequent heavy reliance on humans as their primary blood source. These include the most important vectors of human parasitic diseases, i.e., malaria, dengue and filariasis. Representatives of all three major mosquito genera have made this transition from wild to domestic environments, so this association seems to have evolved independently on several occasions due to similar environmental circumstances. Mosquito feeding preferences are not well understood in terms of either neurobehaviour or genetics but would appear, superficially at least, to be a good target for genetic transformation, i.e., turning human-feeding species into species that seldom feed on humans or transmit their diseases. Understanding how domestic species arose and the current fitness advantages for maintaining those behavioural traits is critical for assessing the potential for manipulating and reversing this process. Aedes aegypti, perhaps the most domesticated of all mosquito species, is used as the prime example in exploring these issue
Host finding, feeding patterns and evidence for a memorized home range of the mosquito Aedes cantans
Recommended from our members
An Improved In Vitro Rearing System for the Human Head Louse allows the Determination of Resistance to Formulated Pediculicides
An improved in vitro rearing system, based on a silicone-reinforced Parafilm® M membrane, human hair tufts and reconstituted human blood, enabled the large-scale rearing of pediculicide-susceptible (EC-HL) and resistant (SF-HL and BR-HL) strains of human head lice. Developmental time differed for early instars but differences became synchronized as lice matured. Mean survivorship amongst the three strains reared in vitro were not significantly different when compared to EC-HL and SF-HL reared in vivo. The efficacies of three pediculicidal products were assessed under semi-clinical conditions using a modified version of the in vitro rearing system. Treatments of 1% permethrin in acetone, Nix®, Rid® or Pronto® Plus to hair tufts following manufacturer’s instructions were highly efficacious (100% mortality) on EC-HL but differentially efficacious (62.2–84.4% mortality) on SF-HL examined eight days post-treatment. SF-HL that survived the first treatment received an identical second treatment eight days following the first treatment. Survivors (13.3–30.0%) developed to adults (10th–11th day following first treatment) and females successfully laid fertile eggs that developed to first instars. These results confirm resistance to permethrin- and pyrethrin-based pediculicide formulations in SF-HL when assessed under semi-clinical conditions and validates resistance previously determined using filter-paper contact bioassays and unformulated insecticides