Not Just from Blood: Mosquito Nutrient Acquisition from Nectar Sources

Abstract

Anthropophilic female mosquitoes are well known for their strong attraction to human hosts, but plant nectar is a common energy source in their diets. When sugar sources are scarce, female mosquitoes of some species can compensate by taking larger and more frequent blood meals. Male mosquitoes are exclusively dependent on plant nectar or alternative sugar sources. Plant preference is likely driven by an innate attraction that may be enhanced by experience, as mosquitoes learn to recognize available sugar rewards. Nectar-seeking involves the integration of at least three sensory systems: olfaction, vision and taste. The prevention of vector-borne illnesses, the determination of the mosquitoes' ecological role, and the design of efficient sugar-baited traps will all benefit from understanding the molecular basis of nectar-seeking. Plant Nectar Is a Common Nutrition Source across Mosquito SpeciesNectar-feeding constitutes an important source of nutrition for adult mosquitoes of both sexes, particularly males, which feed exclusively from plant nectar and require frequent sugar intake for survival [1,2]. This behavior is often underappreciated when compared with blood-feeding because it is during the latter that transmission of pathogens can occur. A few mosquito genera feed solely from plant sources [3], while in hematophagous (see Glossary) species, females consume sugar sources as well as blood. If deprived of sugar, males typically die within 4 days of eclosion [4]. Moreover, lacking the energy reserves needed for flying and copulation that come from a sugar meal, males are unlikely to achieve reproductive success [1]. Although females are less susceptible to rapid mortality caused by sugar deprivation, their survival rate and fecundity can be compromised by reduced energy reserves [1,4]. The sensory cues that enable nectar-feeding include odors [1,2], tastants [5], and visual stimuli [6,7], but the molecular mechanisms of how these cues are perceived, as well as their relative contribution to the detection of a nectar source, are poorly understood (Figure 1). This review highlights the role of sugar feeding in the life cycle of mosquitoes, the plant sources they prefer, the volatiles that attract them, and the contribution of vision, olfaction, and gustation to this behavior.

Self-limiting paratransgenesis

“…Once environmental safety of the anti-Plasmodium compounds is corroborated, Serratia carrying effector genes stably integrated in their chromosome would be constructed. Introduction into the field can be accomplished by mixing the bacteria with attractive sugar baits (both male and female mosquitoes need sugar for survival [18]). Because the engineered Serratia AS1 is sexually transmitted from male to female mosquitoes and is passed from one generation to the next by attaching to eggs, it can efficiently spread into mosquito populations [3].…”

Insect chemical ecology: chemically mediated interactions and novel applications in agriculture

“…Mosquitoes are globally distributed dipterans, and some species are of medical importance, especially those belonging to the family Culicidae (Tandina et al 2018 ). Immediately after eclosion, both males and females feed on nectar or honeydew of plants to get sugars and other nutrients and that provide enough nourishment to live (Barredo and DeGennaro 2020 ). The females, however, need to produce eggs, which require proteins that they get from the blood of vertebrates.…”

“…The females, however, need to produce eggs, which require proteins that they get from the blood of vertebrates. While taking a blood meal, these females, if already infected with the disease-causing pathogens, could transmit the pathogens to their host (i.e., humans or other vertebrates) (WHO 2014 ; Barredo and DeGennaro 2020 ). In order to combat mosquitoes, chemical ecologists have shifted in their conceptual thinking to unravel how mosquitoes recognize and discriminate resources during plant-seeking, host preference, and oviposition sites selection (Ignell and Hill 2020 ).…”

“…Amidst the vast diversity of plants in the environment, mosquitoes face the challenge of locating and discriminating plants with useful resources. Although mosquitoes also rely on vision and taste to find plants, olfaction is relied upon to detect important VOCs and decode them to locate nectar in distant plants (Barredo and DeGennaro 2020 ). Indeed, several studies agreed that mosquitoes rely on volatile chemical signatures, including terpenes, benzenoids, and aldehydes, to assess the suitability of a plant as a potential resource (Healy and Jepson 1988 ; Manda et al 2007 ; Nikbakhtzadeh et al 2014 ; Nyasembe et al 2018 ).…”

Defeating malaria: new weapons against one of our deadliest foes

“…Female mosquitoes also drink blood. 11 An infected female mosquito injects about one hundred sporozoites into a human from the salivary gland during her blood meal. Sporozoites infect liver cells and asexually produce tens of thousands of merozoites.…”