The dry season is an important ecological factor as rainfall is reduced. This can cause changes in water availability for many organisms. Whilst some natural water sources will be reduced or eliminated, there will still be some sources of water. These can include water stored in household containers. Certain mosquito species will have habitats available to them if the water sources in these containers are ideal. This causes questions to be asked about how seasonal changes and water storage in human environments can contribute to the mosquito habitats and populations. It is important to understand how mosquitoes are affected by water availability, temperature and other environmental factors. The relationship of mosquitoes and the dry season is important as it shows how water availability, artificial breeding sites and temperature changes can impact the development of mosquitoes. It is key to understand mosquitoes in an ecologically sensitive way.
The dry season is an important ecological factor which will impact water availability within an ecosystem. Rainfall levels can drastically decrease and this can impact the availability of aquatic habitats. Many natural water sources will be reduced or eliminated. This can reduce suitable breeding sites for certain mosquito species. However, this isn’t always the case as in human environments water can be impacted by human activities. Whilst some natural habitats aren’t suitable for mosquito development, artificial containers in human environments can create breeding sites. According to the WHO, mosquitoes like Aedes aegypti can breed in containers holding water in and around residential areas. This can include empty bottles, old tyres, flowerpots and water storing containers. The availability of mosquito breeding sites depends on the amount of rainfall and environmental factors.
Seasonal changes can have differing impacts on mosquito populations. Research has been carried out in Brisbane, Australia looking at container-breeding mosquitoes and found that changes in human water storage due to drought can impact which containers are suitable for mosquitoes. However, this doesn’t mean that less rainfall will increase mosquito populations. Research was carried out in rural and urban areas of Kenya looking at the breeding sites of Aedes aegypti. It was found that the amount of immature mosquitoes can vary between seasons and locations with the lowest amounts normally being in the long dry season. This shows how complex the relationship is between seasonal changes and mosquito populations. Overall, the impact of the dry season on mosquito populations will depend on the rainfall levels, availability of suitable breeding sites and human activities. It is important to understand these relationships to understand why mosquitoes can be impacted differently in different environments.
Artificial water containers can be found in human environments and can create breeding sites for mosquitoes. These can be separated into two categories. Containers which are used for a purpose such as water in bathrooms, buckets, drums and water tanks. And containers which aren’t used for a purpose such as old tyres, plastic bottles, flowerpot saucers and blocked gutters. According to WHO, there are many water holding containers in residential areas which can create breeding sites for Aedes aegypti. Whether they are suitable depends on the water availability, type of container and environmental factors. Aedes aegypti often breed in domestic containers with relatively clean water. However, other species such as Culex quinquefasciatus can thrive in stagnant water with lots of organic waste. Research was carried out in South Sulawesi, Indonesia and found that stagnant drainage areas with wastewater created suitable breeding sites for Culex quinquefasciatus larvae. Poor waste management, blocked drainage and poor maintenance of water storage containers can increase the number of potential breeding sites. Shade and vegetation can impact the humidity and evaporation of water in the area but this doesn’t guarantee mosquitoes will reproduce. Water can be stored in containers in the dry season for use at home. This can create breeding opportunities. Artificial water sources show how human activities and local environmental factors can impact mosquito breeding. However, this can vary depending on the species and characteristics of each environment.
Temperature is another important environmental factor that affects mosquito development. As ectotherms, mosquitoes require environmental temperatures to regulate their physiological processes such as larval development, reproduction and activity. According to a systematic review by Agyekum et al. (2021), temperature can greatly impact mosquito development, survival, body size and reproductive characteristics. This can vary between species. A review by Villena et al. (2018) explains how temperature can impact the development, distribution and behaviour of Aedes aegypti and Aedes albopictus. During the dry season, increased temperatures can speed up certain stages of mosquito development. However, if temperatures are too high it can impact survival and limit population growth. This is because water sources can dry up meaning there aren’t enough suitable breeding sites. This shows that increased temperatures doesn’t mean there will be more mosquitoes. The amount of mosquitoes will depend on temperature, water availability, suitable breeding sites and can vary between species. It is important to understand these relationships to understand why there can be seasonal variation in mosquito populations. By keeping water storage containers well maintained, removing any discarded items that hold water and ensuring drainage is working well can help reduce potential breeding sites. This is especially important during seasonal changes.
Overall, the relationship between the dry season and mosquitoes shows how complex seasonal biodiversity can be. Less rainfall can cause natural water sources to be reduced. However, artificial containers in human environments can create suitable breeding sites. Temperature and environmental factors can impact mosquito development. This can vary between species. Research was carried out looking at the ecology of mosquitoes in Indonesia and found that multiple species of mosquito can survive in habitats such as rice fields, ex-fish ponds and other water sources during the dry season (Dalilah et al., 2024). This underscores that environmental management strategies should not be uniform rather, they must be grounded in scientific evidence that holistically integrates the specific responses of each species to local microclimatic dynamics. This shows that not all mosquito populations will be impacted in the same way.
The amount of mosquitoes will depend on water availability, temperature, suitable breeding sites and human activities. When looking at mosquito populations during the dry season, it is important to consider the environmental factors of the residential areas. Keeping water storage containers well maintained, removing any discarded items that hold water and keeping drainage clear can help reduce potential breeding sites. This evidence-based approach ensures that interventions are precisely focused on the artificial microhabitats within human settlements, thereby breaking the chain of disease transmission while maintaining the ecological balance of rice paddies and the surrounding aquatic biodiversity. Eventually, looking at mosquito populations from a seasonal biodiversity point-of-view can help give a better understanding of how organisms adapt to environmental changes and why it is important to manage the environment responsibly.
By: Nafilah Nurun Najwa
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