Anopheles Gambiae s.s Attraction to Floral and Human-Skin-Based Odors and Their Combination is Modulated by Previous Bloodmeal Experience

Abstract Background: Mosquitoes use odors in finding energy resources, blood hosts and oviposition sites. While these odor sources are normally spatio-temporally segregated in a mosquito’s life history, here we explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae s.s.Methodology: In the laboratory and in large (80 m2) outdoor cages in Tanzania, nulliparous and parous Anopheles gambiae s.s. were offered choices between a blend of human skin volatiles (Skin Lure), a blend of floral volatiles (Vectrax), or a combination thereof. The blends consisted of odors that induce distinct, non-overlapping activation patterns in the olfactory circuitry, in sensory neurons expressing olfactory receptors (ORs) and ionotropic receptors (IRs), respectively. Catches were compared between treatments. Results: In the laboratory nulliparous and parous mosquitoes preferred skin odors and combinations thereof over floral odors. However, in semi-field settings nulliparous were significantly more caught with floral odors, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness.Conclusions: Nulliparous and parous An. gambiae s.s. are attracted to combinations of odors derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odors sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odors did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odor blends. Results are discussed both from an odor coding, as well as from an application perspective.

Download Full-text

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

10.21203/rs.3.rs-33608/v3 ◽

2020 ◽

Author(s):

ELISON ELIEZA KEMIBALA ◽

Agenor Mafra-Neto ◽

Jesse Saroli ◽

Rodrigo Silva ◽

Anitha Philbert ◽

...

Keyword(s):

Life History ◽

Anopheles Gambiae ◽

Human Skin ◽

Sensory Neurons ◽

Blood Meal ◽

Olfactory Receptors ◽

Developmental State ◽

Sensu Stricto ◽

Monitoring And Control ◽

Activation Patterns

Abstract BackgroundMosquitoes use odours to find energy resources, blood hosts and oviposition sites. While these odour sources are normally spatio-temporally segregated in a mosquito’s life history, here this study explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae sensu stricto (s.s.)MethodsIn the laboratory and in large (80 m2) outdoor cages in Tanzania, nulliparous and parous An. gambiae s.s. were offered choices between a blend of human skin volatiles (Skin Lure), a blend of floral volatiles (Vectrax), or a combination thereof. The blends consisted of odours that induce distinct, non-overlapping activation patterns in the olfactory circuitry, in sensory neurons expressing olfactory receptors (ORs) and ionotropic receptors (IRs), respectively. Catches were compared between treatments.ResultsIn the laboratory nulliparous and parous mosquitoes preferred skin odours and combinations thereof over floral odours. However, in semi-field settings nulliparous were significantly more caught with floral odours, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness.ConclusionsNulliparous and parous An. gambiae s.s. are attracted to combinations of odours derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odours sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.

Download Full-text

Anopheles gambiae attraction to floral and human-skin-based odours and their combination is modulated by previous bloodmeal experience

10.21203/rs.3.rs-33608/v2 ◽

2020 ◽

Author(s):

ELISON ELIEZA KEMIBALA ◽

Agenor Mafra-Neto ◽

Jesse Saroli ◽

Rodrigo Silva ◽

Anitha Philbert ◽

...

Keyword(s):

Life History ◽

Anopheles Gambiae ◽

Human Skin ◽

Sensory Neurons ◽

Blood Meal ◽

Field Experiments ◽

Energy Resources ◽

Kisumu Strain ◽

Oviposition Sites

Abstract Background: Mosquitoes use odours to find energy resources, blood hosts and oviposition sites. These odour sources are normally spatio-temporally segregated in a mosquito’s life history. This study was carried out to determine the attractiveness of Anopheles gambiae to flower- and human-mimicking synthetic volatiles.Methods: This study was carried out in Muheza District in northeast of Tanzania. Anopheles gambiae s.s. Kisumu strain was used in all experiments. The chemicals/odour blends used were Vectrax, skin lure and the combination thereof. The attractiveness of Vectrax and Skin Lure were compared to each other in an insectary and semi-field settings. Semi-field experiments were then conducted using mosquito-spheres. In the two settings, parous or non-parous female mosquitoes, were simultaneously offered four treatments: Skin Lure, Vectrax, a combination of the two, and a control (no attractant). Results: In the insectary nulliparous and parous mosquitoes preferred skin odours and combinations thereof over floral odours. However, in semi-field settings significantly more nulliparous mosquitoes more caught with floral odours, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness.Conclusions: Nulliparous and parous An. gambiae s.s. are attracted to combinations of odours derived from floral and human volatiles. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.

Download Full-text

Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

Parasites & Vectors ◽

10.1186/1756-3305-5-33 ◽

2012 ◽

Vol 5 (1) ◽

Cited By ~ 22

Author(s):

Eliningaya J Kweka ◽

Goufa Zhou ◽

Leila B Beilhe ◽

Amruta Dixit ◽

Yaw Afrane ◽

...

Keyword(s):

Life History ◽

Anopheles Gambiae ◽

Culex Quinquefasciatus ◽

Life History Traits ◽

Anopheles Gambiae S.S

Download Full-text

Human skin microbiota and their volatiles as odour baits for the malaria mosquito Anopheles gambiae s.s

Entomologia Experimentalis et Applicata ◽

10.1111/j.1570-7458.2011.01119.x ◽

2011 ◽

Vol 139 (2) ◽

pp. 170-179 ◽

Cited By ~ 27

Author(s):

Niels O. Verhulst ◽

Wolfgang R. Mukabana ◽

Willem Takken ◽

Renate C. Smallegange

Keyword(s):

Anopheles Gambiae ◽

Human Skin ◽

Malaria Mosquito ◽

Skin Microbiota ◽

Anopheles Gambiae S.S ◽

Mosquito Anopheles Gambiae

Download Full-text

The potential of human skin and plant-based odours combination to attract malaria mosquito, Anopheles gambiae s.s. in Laboratory and Semi field settings.

10.21203/rs.2.22062/v1 ◽

2020 ◽

Author(s):

ELISON ELIEZA KEMIBALA ◽

Agenor Mafra-Neto ◽

Teun Dekker ◽

Jesse Saroli ◽

Rodrigo Silva ◽

...

Keyword(s):

Anopheles Gambiae ◽

Human Skin ◽

Field Trials ◽

Mosquito Vector ◽

Anopheles Gambiae S.S ◽

Comparison Results ◽

Vector Management ◽

Mosquito Anopheles Gambiae ◽

And Control ◽

Field Setting

Abstract Background Knowledge on mosquito attraction to various host-mimicking odors provides a potential opportunity for designing effective tools for surveillance and control of potential disease vectors. This study was carried out to explore the potential of combining plant and human mimicking odours to attract Anopheles gambiae s. s . in the laboratory and semi field settings in Tanzania. Methodology Blood fed and unfed female Anopheles gambiae s.s. mosquitoes were offered choices between human skin, plant-based odours or combination thereof in laboratory and semi-field setting. The captured mosquitoes from each source were scored for comparison. Results In laboratory and semi-field trials, the tested attractants combination of plant and human-mimicking odours found to be slightly attractive (approximately 10% higher) than either individual attractant to blood fed female mosquitoes under lab and semi-field settings. The unfed female mosquitoes were more attracted to Vectrax (plant-based materials) by more than 10% in comparison to human skin-based attractant both in lab and semi-field settings. In semi-field settings particularly, more unfed female mosquitoes were attracted to Vectrax than to the combination (p < 0.01). Conclusions The findings that the combination blend (human host and plant based) semiochemical increases mosquito attraction hold the potential to increase efficiency of mosquitoes trapping devices in both indoor and outdoor settings. This may provide valuable tools for mosquito vector management programs. Moreover, these results also suggest the potential of the combination odours to be used in the attract and kill strategies.

Download Full-text