Oldest known fossil shows male mosquitoes once sucked blood
Scientists researching the oldest known mosquito fossil have made a remarkable discovery about the evolution of the bloodsucking insects from 130 million years ago
READING LEVEL: ORANGE
A startling discovery has been made about the evolution of mosquitoes after researchers found the oldest-known fossils of the insect in Lebanon. The pair of male mozzies were preserved in pieces of amber dating up to 130 million years ago.
To the scientists’ surprise, the male mosquitoes had elongated piercing-sucking mouthparts designed for sucking blood.
The feature was unexpected because in modern mosquitoes, only fertilised females feed on blood.
“Males and unfertilised females will eat some nectar from plants. And some males do not feed at all,” said palaeontologist and lead author of the research Professor Dany Azar from the Chinese Academy of Sciences’ Nanjing Institute of Geology and Palaeontology and Lebanese University. “Only fertilised female mosquitoes will suck blood, because they need proteins to make their eggs develop.”
The discovery of the fossilised males shows that during the cretaceous period all mosquitoes were blood suckers and that males eventually lost the need to drink blood over time.
“So this discovery is a major one in the evolutionary history of mosquitoes,” Prof Azar said.
The two fossilised mosquitoes, both from the same extinct species, are similar in size and appearance to modern mosquitoes, though the mouthparts used for obtaining blood are shorter than those in today’s female mosquitoes.
The delicate anatomy of the two mosquitoes was well preserved in the fossils. Both had very sharp, triangle-shaped jaws and an elongated sucker.
“Finding this behaviour in the Cretaceous is quite surprising,” said palaeontologist and study co-author Professor André Nel of the National Museum of Natural History of Paris.
The researchers said they suspected mosquitoes evolved from insects that did not consume blood and that the mosquito’s piercing sucker developed from suckers used to eat plant nectar.
Plant evolution may have played a role in males eventually choosing plant nectar over blood for their dinner. At the time when these two mosquitoes became stuck in tree sap that eventually became amber, flowering plants were beginning to flourish for the first time.
The fact that these earliest-known mosquitoes are bloodsucking males, Prof Azar said, “means that originally the first mosquitoes were all haematophagous – no matter whether they were males or females – and haematophagy was later lost in males, maybe due to the appearance of flowering plants.”
Plenty of animals were present to provide blood meals: dinosaurs, flying reptiles called pterosaurs, other reptiles, birds and mammals.
The researchers said while the fossils were the oldest found, mosquitoes probably originated millions of years earlier. Molecular evidence suggests mosquitoes came into being during the Jurassic Period, which ran from about 200 million to 145 million years ago.
There are more than 3500 species of mosquitoes worldwide, found everywhere except Antarctica. Some can spread diseases like malaria, yellow fever, Zika fever and dengue fever.
“Mosquitoes are the most notorious blood-feeders on humans and most terrestrial vertebrates, and they transmit a certain number of parasites and diseases to their hosts,” Prof Azar said.
“On the other side, mosquitoes help to purify the water in ponds, lakes and rivers,” Prof Nel said. “In general, an animal can be a problem but also can be helpful.”
POLL
GLOSSARY
- elongated: long or stretched out
- fertilised: carrying eggs
- unfertilised: not carrying eggs
- anatomy: body parts
- haematophagous: bloodsucking
- haematophagy: the characteristic of sucking blood
- molecular evidence: findings from DNA studies
- terrestrial vertebrates: land animals that have spines
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QUICK QUIZ
1. How old were the mosquito fossils?
2. Which prehistoric period did they date back to?
3. Why do female mosquitoes drink blood?
4. What are two diseases that can be spread by mosquitoes?
5. When do scientists think the first mosquitoes came into being?
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CLASSROOM ACTIVITIES
1. Mosquito evolution
Draw a diagram with an explanation of how mosquitoes have evolved over time, 130 million years ago to now.
Mention things like what they eat, what they looked like, etc.
Present your answers in a structured way that is easy to read and compare.
Time: allow 30 minutes to complete this activity
Curriculum Links: English, Science, Critical and Creative Thinking
2. Extension
Write the benefits and risks associated with mosquitoes.
Time: allow 15 minutes to complete this activity
Curriculum Links: English, Science, Critical and Creative Thinking
VCOP ACTIVITY
Explicit lesson plan: Who likes bugs?
Objective: This activity aims to encourage curiosity and critical thinking while having fun exploring the fascinating world of insects and the unexpected secrets they hold!
Instructions:
Start your lesson by discussing how animals adapt to changes in their environment over time. Prompt the students to share examples of adaptations they know about in other animals. Then, ask them to predict how mosquitoes may have adapted over millions of years. Have students pair up and list two things they know about mosquitoes before reading the article.
Next, partner read the article before engaging the students in a group discussion using these questions:
a. Ask the class: “Who likes bugs?” Discuss the different insects they know.
b. What was the surprising discovery about mosquitoes’ past diets?
c. How are the oldest-known mosquitoes different from today’s mosquitoes?
Reflective Discussion: Wrap up the introduction by asking students to discuss the importance of mosquitoes in nature. Encourage them to highlight their role as both problematic disease carriers and beneficial creatures in ecosystems. Ask them to think about how these contrasting roles impact humans and the environment. Encourage the students to share their thoughts with another pair.
Based on the age and ability of the students, choose an appropriate activity from below:
Reflective Writing: Provide journals and ask students to write a short paragraph about what they found most surprising about the mosquito discovery and why.
Encourage students to re-read their work to make sure it is clear and makes sense, before sharing it with someone else. Editing Prompt: Can you edit and Uplevel any of your VCOP to make your writing more engaging for the audience?
Debate: Split the class into two teams – Team Bloodsucker and Team Nectar Drinker. Have a friendly debate about whether mosquitoes should drink blood or nectar.
Additional Tasks:
Drawing Activity: Give each student paper and crayons. Ask them to draw what they think the prehistoric mosquitoes looked like and how they behaved. Share and discuss their drawings.
Role Play Time Travel: Imagine travelling back in time to the period of dinosaurs. Role-play as a curious explorer finding the ancient mosquitoes and speculating on what life was like then.
Guess the Insect Behaviour: Play a game: “Guess the Behaviour.” Describe various insects and ask students to guess their behaviour (e.g., butterflies drink nectar, ants gather food). Then reveal the surprising mosquito fact!
Allow the children to share their stories or drawings with the class. Encourage discussions about what they included in their stories or drawings and why they made those choices. Introduce peer or personal feedback as a way of reflecting on their learning.
Conclude the session by allowing the children to share their stories or drawings with the class. Encourage discussions about what they included in their stories or drawings and why they made those choices. Introduce peer or personal feedback as a way of reflecting on their learning.