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The importance of temperature fluctuations in understanding mosquito population dynamics and malaria risk

View Article: PubMed Central - PubMed

ABSTRACT

Temperature is a key environmental driver of Anopheles mosquito population dynamics; understanding its central role is important for these malaria vectors. Mosquito population responses to temperature fluctuations, though important across the life history, are poorly understood at a population level. We used stage-structured, temperature-dependent delay-differential equations to conduct a detailed exploration of the impacts of diurnal and annual temperature fluctuations on mosquito population dynamics. The model allows exploration of temperature-driven temporal changes in adult age structure, giving insights into the population’s capacity to vector malaria parasites. Because of temperature-dependent shifts in age structure, the abundance of potentially infectious mosquitoes varies temporally, and does not necessarily mirror the dynamics of the total adult population. In addition to conducting the first comprehensive theoretical exploration of fluctuating temperatures on mosquito population dynamics, we analysed observed temperatures at four locations in Africa covering a range of environmental conditions. We found both temperature and precipitation are needed to explain the observed malaria season in these locations, enhancing our understanding of the drivers of malaria seasonality and how temporal disease risk may shift in response to temperature changes. This approach, tracking both mosquito abundance and age structure, may be a powerful tool for understanding current and future malaria risk.

No MeSH data available.


Related in: MedlinePlus

Annual cycles of abundance from one mean temperature (26°C) with three different seasonal drivers. Annual cycles of adult mosquito abundance (orange solid lines), abundance of potentially infectious mosquitoes (dashed orange lines) and the temperature fluctuation (grey line or band). The abundance is number of mosquitoes per litre of larval habitat. (a) 12°C annual temperature range, (b) 8°C diurnal temperature range and (c) 8°C diurnal temperature range nested within a 12°C annual temperature range.
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RSOS160969F1: Annual cycles of abundance from one mean temperature (26°C) with three different seasonal drivers. Annual cycles of adult mosquito abundance (orange solid lines), abundance of potentially infectious mosquitoes (dashed orange lines) and the temperature fluctuation (grey line or band). The abundance is number of mosquitoes per litre of larval habitat. (a) 12°C annual temperature range, (b) 8°C diurnal temperature range and (c) 8°C diurnal temperature range nested within a 12°C annual temperature range.

Mentions: Examining predicted population abundances across the temperature fluctuations at a single mean temperature, we found that the size and type of fluctuation can greatly alter the predicted population outcome (figure 1 and electronic supplementary material, S3–S5). To illustrate this, we focused on three of the fluctuating temperature drivers with a mean temperature of 26°C. We found that adult mosquito abundance was predicted to have a very slight seasonal dip with the 12°C annual temperature range, to be constant over time with the 8° diurnal temperature range, and to go through a seasonal crash when those two drivers were combined (figure 1). The predicted abundance of potentially infectious mosquitoes showed similar differences between temperature fluctuations. This result was even more notable as the size differences between the compared fluctuations increased or when the mean temperature was closer to the edge of the temperature range explored.Figure 1


The importance of temperature fluctuations in understanding mosquito population dynamics and malaria risk
Annual cycles of abundance from one mean temperature (26°C) with three different seasonal drivers. Annual cycles of adult mosquito abundance (orange solid lines), abundance of potentially infectious mosquitoes (dashed orange lines) and the temperature fluctuation (grey line or band). The abundance is number of mosquitoes per litre of larval habitat. (a) 12°C annual temperature range, (b) 8°C diurnal temperature range and (c) 8°C diurnal temperature range nested within a 12°C annual temperature range.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383843&req=5

RSOS160969F1: Annual cycles of abundance from one mean temperature (26°C) with three different seasonal drivers. Annual cycles of adult mosquito abundance (orange solid lines), abundance of potentially infectious mosquitoes (dashed orange lines) and the temperature fluctuation (grey line or band). The abundance is number of mosquitoes per litre of larval habitat. (a) 12°C annual temperature range, (b) 8°C diurnal temperature range and (c) 8°C diurnal temperature range nested within a 12°C annual temperature range.
Mentions: Examining predicted population abundances across the temperature fluctuations at a single mean temperature, we found that the size and type of fluctuation can greatly alter the predicted population outcome (figure 1 and electronic supplementary material, S3–S5). To illustrate this, we focused on three of the fluctuating temperature drivers with a mean temperature of 26°C. We found that adult mosquito abundance was predicted to have a very slight seasonal dip with the 12°C annual temperature range, to be constant over time with the 8° diurnal temperature range, and to go through a seasonal crash when those two drivers were combined (figure 1). The predicted abundance of potentially infectious mosquitoes showed similar differences between temperature fluctuations. This result was even more notable as the size differences between the compared fluctuations increased or when the mean temperature was closer to the edge of the temperature range explored.Figure 1

View Article: PubMed Central - PubMed

ABSTRACT

Temperature is a key environmental driver of Anopheles mosquito population dynamics; understanding its central role is important for these malaria vectors. Mosquito population responses to temperature fluctuations, though important across the life history, are poorly understood at a population level. We used stage-structured, temperature-dependent delay-differential equations to conduct a detailed exploration of the impacts of diurnal and annual temperature fluctuations on mosquito population dynamics. The model allows exploration of temperature-driven temporal changes in adult age structure, giving insights into the population’s capacity to vector malaria parasites. Because of temperature-dependent shifts in age structure, the abundance of potentially infectious mosquitoes varies temporally, and does not necessarily mirror the dynamics of the total adult population. In addition to conducting the first comprehensive theoretical exploration of fluctuating temperatures on mosquito population dynamics, we analysed observed temperatures at four locations in Africa covering a range of environmental conditions. We found both temperature and precipitation are needed to explain the observed malaria season in these locations, enhancing our understanding of the drivers of malaria seasonality and how temporal disease risk may shift in response to temperature changes. This approach, tracking both mosquito abundance and age structure, may be a powerful tool for understanding current and future malaria risk.

No MeSH data available.


Related in: MedlinePlus