Primary Science


Solving the 2021 PSLE Science Mosquito Question (Life Cycle)

What are the Biotic & Abiotic Factors Affecting Mosquitoes Population?

Abiotic factors, such as the environment’s temperature, play a crucial role in the survival of insects. But what exactly are abiotic factors?

In essence, these are non-living components of an ecosystem that can greatly influence living organisms.

The acronym FAT PIGS can help you to remember the following physical factors:

  • Food
  • Amount of air
  • Temperature
  • Presence of water
  • Intensity of light
  • Ground materials
  • Shade


How mosquitoes pose a danger to humans?

Now, let’s dive into the mosquito world. These tiny creatures are found almost everywhere on our planet, except for Antarctica. They’ve adapted to a variety of ecosystems but often grab our attention for all the wrong reasons.

Mosquitoes are notorious for spreading diseases like malaria, yellow fever, Zika, dengue, and chikungunya, collectively responsible for nearly one million human deaths each year.


Among mosquitoes, two species—Aedes aegypti, the yellow fever mosquito, and Aedes albopictus, the Asian tiger mosquito which causes dengue fever —have received a lot of attention in the past decade.

The two species look similar, but we can tell them apart by examining their scale patterns. Aedes aegypti has two white bands on its thorax in the shape of a lyre, whereas Aedes albopictus has one white central band.


Let’s Investigate How Temperature Affects the Mosquito Population

Now, how does temperature come into play in all of this? The environment’s temperature can significantly impact mosquito populations by influencing the development stages (i.e., eggs, larvae, and pupae).


Higher temperatures speed up development, meaning that mosquito larvae turn into adults much faster in warmer conditions. The ideal temperature for hatching mosquito eggs hovers between 22°C and 27°C. Any cooler, and the larvae become lethargic, while at higher temperatures like 38°C, fewer eggs hatch.

Here’s a fun fact: the best development time for mosquito larvae falls at around 32°C. However, at lower temperatures of 8 °C, the larvae will barely move, and die within a couple of days.


So why should you concern yourself with this? Well, it’s all about understanding the link between climate change, global warming, and the spread of mosquitoes. With rising global temperatures, mosquito populations are on the rise too.

Now, let’s attempt to solve this tricky PSLE Science 2021 Mosquito Question together!

2021 PSLE Science Mosquito Question (Q32)

Q32. George wanted to find out about conditions that affect the breeding of mosquitoes.

In an experiment, George recorded the number of mosquito eggs that hatched in a day out of 20 eggs at different temperatures. He repeated the experiment two more times.

His results are as shown.

Temperature ( °C) Number of eggs that hatched in a day
Temperature 1st experiment 2nd experiment 3rd experiment
22 8 12 13
28 16 17 19
38 2 0 4

(a) Describe what George could conclude about the effect of temperature on the hatching of mosquito eggs. [2]

The higher the temperature, the more the number of hatched mosquito eggs. However until 38 degrees Celsius, the number of mosquito eggs hatched in a day decreases.


Mosquito development is influenced by temperature. The ideal hatching temperature is between 22 and 27°C.

This is a common relationship question. Students are expected to observe that as the temperature increases from 22 to 28°C, the number of hatched mosquito eggs increases. Then, at 38°C, the number of hatched mosquito eggs decreases.


Both the increasing and decreasing relationships must be stated! This question is under the P4 topic of life cycles.

Interested to know how your child can tackle challenging PSLE questions easily?

2021 PSLE Science Mosquito Question experiment

To correctly answer these questions, students must possess a firm grasp of various topics, such as life cycles and interactions within the environment, and apply this knowledge in a skillful manner. At BlueTree, we empower our students to tackle these complex questions with confidence, equipping them with the skills they need to navigate even the most intricate exam questions. After all, it’s this resilience and preparedness that often set apart our students to excel in the PSLE/ Primary exams.

If you are interested to find out more about our classes, find out more about upcoming intake here.

Read Also: How to Tackle PSLE Science Questions on Adaptations?