Discriminative feeding behaviour of Anopheles gambiae s.s. on endemic plants in western Kenya

Abstract

Anopheles gambiae Giles s.s. (Diptera: Culicidae) is known to feed on plant sugars, but this is the first experimental study to consider whether it discriminates between plant species. Thirteen perennial plant species were selected on the basis of their local availability within the vicinity of human dwellings and larval habitats of An. gambiae s.s. in western Kenya. Groups of 100 or 200 mosquitoes were released into cages either with a cutting of one plant type at a time (single-plant assay) or with cuttings of all 13 plants simultaneously (choice assay), respectively, and left overnight. In the choice assay, direct observations of the percentages of mosquitoes perching or feeding on each plant were recorded over four 1-h periods each night. For both types of assay, mosquitoes were recaptured and the percentage that had fed on plants was assessed by testing them individually for the presence of fructose. To identify which plants the choice-assay mosquitoes had fed on, gas chromatography (GC) profiles of samples of mosquito homogenates were compared with GC profiles of extracts from relevant parts of each plant. Four of the plants that were observed to have been fed on most frequently in the choice assay (Parthenium hysterophorus L., Tecoma stans L., Ricinus communis L., and Senna didymobotrya Fresen) were also shown to have been ingested most often by mosquitoes in both types of assay, suggesting that An. gambiae is differentially responsive to this range of plants, regardless of whether the plants were presented singly or mixed together. Significantly more females than males fed on plants, with the exception of P. hysterophorus L., one of the plants most frequently fed on. For most plant species (ten of 13), GC profiles indicated that An. gambiae obtained sugars primarily from flowers. The exceptions were P. hysterophorus L., Lantana camara L. and R. communis L., on which An. gambiae fed more often from leaves and stems than from flowers.

Effects of Plant-Community Composition on the Vectorial Capacity and Fitness of the Malaria Mosquito Anopheles gambiae

“…Plants used in the sugar-poor environment were Tithonia diversifolia (Asteraceae), Parthenium hysterophorus (Asteraceae), Lantana camara (Verbenaceae), and Datura stramonium (Solanaceae). Although P. hysterophorus was reported to give a high level of fructose positivity in one study, 24 survival was Figure 1. Interior of one mesocosm, showing resting pots, oviposition sites, lights, temperature and humidity sensors, a chair for the blood host, and nectariferous plants.…”

“…gambiae exposed to them had been studied. 14,17,18,24 Plants showing a high level of sugar output and extended mosquito survival in those studies were used in the sugar-rich environment. These plants were Senna didymobotrya (Fabaceae), Ricinus communis (Euphorbiaceae), and Tecoma stans (Bignoniaceae); Senna occidentalis (Fabaceae) was also included in this category because of prior observations of An.…”

The sugar meal of the African malaria mosquito Anopheles gambiae (Giles) and how deterrent compounds interfere with it: a behavioural and neurophysiological study

“…In the field, mosquitoes are generally observed to feed on flowers in full bloom that are abundant, demonstrating opportunism (Magnarelli, 1979). However, in the African malaria mosquito Anopheles gambiae (Giles), some clear preferences exist for particular plants available in the vicinity of human hosts or oviposition sites (Manda et al, 2007b). To date, the physiological basis in A. gambiae for discriminating between plant species is still unknown.…”

“…Plant-derived sugar is the basic food of adult mosquitoes (Foster, 1995), usually including sucrose, which is also the most common sugar in nectar, along with fructose and glucose (Wykes, 1952;Baker and Baker, 1982;Van Handel, 1984;Petanidou and Lamborn, 2005;Manda et al, 2007b). Carbohydrates are consumed by males to supplement the energy required for their intense swarming (Yuval et al, 1994;Gary et al, 2009).…”

Mosquito Biting and Movement Rates as an Emergent Community Property and The Implications for Malarial Interventions

“…This provides managers with opportunities for managing malaria via community manipulation via plants and predators. Area-wide reduction in mosquito-favored plants (Manda et al, 2007) skews populations to the left and would reduce inter-domicile movement and/or increase resting and encounters with predators via increased sugar foraging.…”