Evaluation of Moringa oleifera seed lectin in traps for the capture of Aedes aegypti eggs and adults under semi-field conditions

Abstract

The water-soluble lectin isolated from Moringa oleifera seeds (WSMoL) is a larvicidal, ovicidal, and oviposition-stimulating agent against Aedes aegypti under laboratory conditions. This study investigated the effect of WSMoL in traps for the capture of A. aegypti eggs and adult females under semi-field conditions and determined whether gravid females could detect WSMoL by an olfactory response. WSMoL was isolated according to a previously described procedure using chitin chromatography. The bioassays were performed in large cages (12.5 m(3)). Two traps for collection of eggs (ovitrap) or adult mosquitoes (MosquiTRAP(TM)) were placed in a cage. One was filled with WSMoL (0.1 mg/mL) and the other with tap water (negative control). An infusion of Panicum maximum leaves was used as a positive control. Forty gravid females were then released in each cage. After 2 (for oviposition) or 3 h (for female capture), the traps were removed, and the number of eggs or females was counted. An olfactometry assay was performed to investigate whether the effect of WSMoL on gravid females was linked to an olfactory response. WSMoL showed an oviposition-stimulating effect (65 ± 14%) that was similar (p < 0.05) to that promoted by the P. maximum infusion (67 ± 11%). The efficiency of MosquiTRAP(TM) in capturing gravid females was not increased by WSMoL. The olfactometry assay indicated that the response of females to WSMoL did not involve the stimulation of olfactory sensilla. WSMoL effectively captured eggs when used in ovitraps under semi-field conditions; this property, together with the ovicidal and larvicidal activities of this lectin, makes it an interesting candidate for A. aegypti control.

Arbovirus Vectors of Epidemiological Concern in the Americas: A Scoping Review of Entomological Studies on Zika, Dengue and Chikungunya Virus Vectors

“…Brown et al [36] studied the combined effects of temperature and ecosystem type on distance travelled before oviposition, and found it to be limited at high temperature and low humidity. Santos et al [37] studied the effects of WSMoL as an oviposition stimulant, and its mechanism. They found it to be effective under semi-field conditions through its effects on gustatory sensillia [37].…”

“…Santos et al [37] studied the effects of WSMoL as an oviposition stimulant, and its mechanism. They found it to be effective under semi-field conditions through its effects on gustatory sensillia [37]. Wermelinger et al [38], Valenca et al [39] and Chadee and Martinez [40] observationally studied oviposition site preference of Ae.…”

Measuring the Host-Seeking Ability of Aedes aegypti Destined for Field Release

“…[65][66][67] Semi-field experiments have been used to test the mating success and invasive ability of Wolbachia infections 8,68,69 and for evaluating the efficacy of novel mosquito traps and pesticides. 67,70,71 Although host seeking is critical to the success of Wolbachia-based population replacement programs, the strains used in field releases have only been tested in laboratory studies 72 and not in a realistic context.…”

Measuring the host-seeking ability of Aedes aegypti destined for field release

“…63, 64, 65 Semi-field experiments have been used to test the mating success and invasive ability of Wolbachia infections 12, 66, 67 and for evaluating the efficacy of novel mosquito traps and pesticides. 65, 68, 69 But while host-seeking is critical for the success of Wolbachia replacement programs, the strains used in field releases including w Mel and w AlbB have not been evaluated for their effects on host-seeking ability in a realistic way.…”