Effect on mosquitoes

LIfe cycle of mosquitoes (4 stages)

1. Egg (terrestrial phase): female mosquitoes lay eggs above waterline of containers with water

2. Larvae (aquatic phase):

• Larvae hatch when water inundates eggs

• Larvae feed on microorganisms and organic matter in water

• Go through 1st-4th instars (developmental stages) where they molt/shed skin three times

3. Pupa (aquatic phase): metamorphosis triggered after fourth instar, chanigng larva into pupa. Pupa does not feed.

4. Adult (terrestrial phase): fully developed adult mosquito emerges from water after breaking pupa skin. Adult can fly and is has terrestrial habitat

Effect of temperature on life cycle of mosquito(aedes aegypti)

1. Egg:

• Significantly higher hatching rate at lower temperatures(15-30C)

• optimium is 25C

2. Larva:

• highest larval survival rate at 25C and lowest at 40C

• shorter development time at warmer temperatures

3. Pupa

• highest pupal survival rate at 25C

Overall: Warmer conditions speed up the entire life cycle, leading to more generations in a season. Disease transmission also accelerates due to increase in population.

Overall impact of global warming on spread of mosquito-borne diseases

1. extended transmission seasons: mosquitoes survive for longer in warmer temperatures, increasing duration of transmission of disease

2. expansion of geographical range: rising temperatures create favourable conditions for mosquitoes to breed in new areas/higher altitude

3. more breeding grounds: Changes in rainfall lead to mroe stagnant water for breeding but droughts in some areas may reduce mosquito populations

4. (for malaria)Faster parasite development: plasmodium parasite develops more quickly inside mosquitoes at higher temperatures, raising infection rates

5. increased mosquito activity (due to increase in rate of development, shortening the lifecycle period, improved survival of eggs and adult mosquitoes)

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