Evaluations of dual attractant toxic sugar baits for surveillance and control of Aedes aegypti and Aedes albopictus in Florida

Abstract

BackgroundDual attractant toxic sugar baits (D-ATSB) containing two host kairomones, L-lactic (LA) and 1-octen-3-ol (O), and fruit-based attractants were evaluated through olfactory, consumption and mortality, and semi-field experiments to determine if host kairomones could first, enhance attraction of a fruit-based (attractant) toxic sugar bait (ATSB), and second, increase the efficacy of a fruit based attractive toxic sugar bait (ATSB).MethodsFour combinations of LA and O were incorporated into the ATSB and evaluated in an olfactometer to determine if these combinations could enhance attraction of Aedes aegypti (L.) to the bait. Ae. albopictus (Skuse) and Ae. aegypti were used to determine bait consumption through excrement droplet counts and percent mortality, of the most attractive D-ATSB (1% LA and 1% O) from the olfactory study. Semi-field evaluations were conducted in screened portable field cages to determine if the D-ATSB applied to non-flowering plants controlled more mosquitoes than the fruit-based ATSB, and ASB. Mosquitoes were exposed to D-ATSB and the two controls for 48 h and collected with BGS traps. The catch rates of the BGS traps were compared to determine efficacy of the D-ATSB.ResultsDuring olfactometer evaluations of D-ATSB, Ae. aegypti mosquitoes were more attracted to 1% LA and 1% O compared to the fruit-based toxic sugar bait alone. Both species of mosquito consumed more fruit-based non-toxic bait (ASB) and ATSB than the D-ATSB. For both species, percent mortality bioassays indicated D-ATSB controlled mosquitoes, as compared to non-toxic control, but not more than the fruit based ATSB. Semi-field evaluations, BioGents sentinel traps at 48 h confirmed that ATSB (positive control) controlled Ae. albopictus, but there was no statistical difference between ASB (negative control) and the D-ATSB. No differences were observed between the mosquitoes caught in any of the experimental formulations for Ae. aegypti.ConclusionsL-lactic (1%) and 1-octen-3-ol (1%) added to a fruit-based sugar bait increased attraction of Ae. aegypti and may have future implications in mosquito trapping devices. The addition of the host kairomones did not enhance the consumption and efficacy of the ATSB in laboratory or semi-field evaluations for both mosquito species. We attribute to the absence of other host cues leading to lack of alighting onto bait surfaces to imbibe the toxic bait, as well as a possible decrease in palatability of the bait caused by the addition of the host kairomones.

Is Anopheles gambiae attraction to floral and human skin-based odours and their combination modulated by previous blood meal experience?

“…In this study, although mosquitoes were attracted to a combination of oral and human odour, the combination did not augment or synergize capture rates, in spite of each blend individually being attractive. This is largely in line with earlier reports [36][37][38][39]. In a recent eld studies in Kenya, a combination of plant-and human-derived odours was observed to elicit a masking effect in trapping Aedes aegypti [38].…”

“…Over the past 60 years, attraction of female mosquitoes to blood-host mimicking odours and plant-based attractants has rarely combined odours from different origin [46][47][48][49][50][51][52][53]. In those studies, where odours of presumed oral and vertebrate origin were combined, mixed results were obtained, by and large not indicating synergy [36][37][38][39]. In this study, although mosquitoes were attracted to a combination of oral and human odour, the combination did not augment or synergize capture rates, in spite of each blend individually being attractive.…”

The Mosquito Electrocuting Trap As An Exposure-Free Method For Measuring Human Biting Rates ByAedesMosquito Vectors

“…Fay [56], the Fay-Prince trap [57], the black cylinder suction trap [58], duplex cone trap [59]) and lure-based traps. For the latter, artificial odours and attractants have been developed and tested for use in traps such as kairomone blends [60][61][62][63][64][65][66][67], BG-Lure® cartridges [68][69][70], and carbon dioxide (CO2) 6 [71]. Additionally other trapping methods have been developed that use live hosts as lures (e.g.…”

The sugar substitute Stevia shortens the lifespan of Aedes aegypti potentially by N-linked protein glycosylation

“…Attractive-toxic sugar baits (ATSB) are promoted as one of the new vector control paradigms because this method kills both female and male mosquitoes questing for essential sugar sources in the outdoor environment 10,11 . ATSB solutions have three main components: (1) fruit or flower scent as an attractant, (2) sugar solution as a feeding stimulant, and (3) oral toxin to kill the mosquitoes 11 . The ATSB's may further be simplified by using non-nutritive sugar substitutes instead of sugar solution and oral toxin.…”