Data from: Alteration of plant-species assemblages can decrease the transmission potential of malaria mosquitoes

1. Knowledge of the link between a vector population’s
pathogen-transmission potential and its biotic environment can generate
more realistic forecasts of disease risk due to environmental change. It
also can promote more effective vector control by both conventional and
novel means 2. The present study assessed the effect of particular
plant-species assemblages differing in nectar production on components of
the vectorial capacity of the mosquito Anopheles gambiae s.s., an
important vector of African malaria. 3. We followed cohorts of mosquitoes
for 3 weeks in greenhouse mesocosms holding nectar-poor and nectar-rich
plant species, by tracking daily mortalities and estimating daily biting
rates and fecundities. At death, a mosquito’s insemination status and wing
length were determined. These life-history traits allowed incorporation of
larval dynamics into a vectorial capacity estimate. This new study
provided both novel assemblages of putative host plants and a human blood
host within a nocturnal period of maximum biting. 4. Survivorship was
significantly greater in nectar-rich environments than nectar-poor ones,
resulting in greater total fecundity. Daily biting rate and fecundity per
female between treatments was not detected. These results translated to
greater estimated vectorial capacities in the nectar-rich environment in
all four replicates of the experiment (means: 1,089.5 ± 125.2 vs. 518.3 ±
60.6). When mosquito density was made a function of survival and
fecundity, rather than held constant, the difference between plant
treatments was more pronounced, but so was the variance, so differences
were not statistically significant. In the nectar-poor environment,
females’ survival suffered severely when a blood-host was not provided. A
sugar-accessibility experiment confirmed that Parthenium hysterophorus is
a nectar-poor plant for these mosquitoes. Synthesis and applications: This
study, assessing the effect of particular plant species assemblages on the
vectorial capacity of malaria mosquitoes, highlights the likelihood that
changes in plant communities (e.g., due to introduction of exotic or
nectar-rich species) can increase malaria transmission and that a
reduction of favourable nectar sources can reduce it. Also, plant
communities’ data can be used to identify potential high risk areas.
Further studies are warranted to explore how and when management of plant
species assemblages should be considered as an option in an integrated
vector management (IVM) strategy.