Flight behaviour of hungry malaria mosquitoes analysed

May 06, 2013
Flight behaviour of hungry malaria mosquitoes analysed

Malaria mosquitoes go to work cautiously before landing on human skin and biting. Just before a mosquito lands, it reacts to both odours and heat given off by the human body. Researchers at Wageningen University came to this conclusion after studying images made with infrared-sensitive cameras. Their research was published in the scientific journal PLOS ONE on 2 May.

Most prefer . They fly in the dark while their host is sleeping. In order to locate a host, they focus on traces of carbon dioxide, released by all animals, and on characteristic human odours. At a distance of 1.5 m from their host, they mainly follow body odours. Just before they land, however, heat radiating from the human body also plays a significant role.

The researchers and technicians at Wageningen University, which is part of Wageningen UR, worked with colleagues from Noldus Information Technology BV using video recordings and automated 3D image analyses to clarify how malaria find their host.

In order to investigate seeking behaviour in mosquitoes, the researchers placed the insects in a special dark wind tunnel measuring 60 by 60 cm, with a length of 1.6 m. The air stream had a constant temperature and humidity, and a speed of 20 cm/second. The flight of each mosquito () in the tunnel was filmed by means of infrared-sensitive cameras.

Wind tunnel with the flight route of a malaria mosquito. On the left, without odour source; on the right, with source of odour and heat. The air stream in the tunnel goes from right to left. The mosquito starts at the left-hand side and flies against the air stream. If no odours are present, the mosquito lands on the right-hand wall after only a few seconds. When odour and heat are present the mosquito takes a longer (on average, four times longer) and more complex route to the odour source, and then proceeds to land.

When human odours were absent, the mosquitoes continued to fly into the wind through the tunnel. As soon as the researchers added an odour to the air stream, the mosquitoes followed a complex and long route to the source, and this took about twice as long as without odours. Adding a (34°C, the same as ) again doubled the length of the search and was crucial for finding the odour source. Adding heat caused the to change drastically whenever mosquitoes came near (about 20 cm) to the source. The exact mechanism of landing will be the subject of a future investigation.

This research at Wageningen demonstrates that the interaction of odour and heat is effective in bringing mosquitoes to a host. This is the first study to make malaria mosquito flight behaviour 'visible' in the dark and it demonstrates that insects are extremely good at orientating themselves towards their host at night. This discovery means that existing odour traps can be enhanced by, for example, adding a source of heat, or by changing the position of the bait in relation to the trap opening. This is one of the ways of controlling malaria, still a serious disease affecting millions of people in large parts of the world. The new information on transmission by the malaria mosquito can be used to combat the disease more effectively.

Explore further: Genomes of malaria-carrying mosquitoes sequenced

More information: Spitzen, J. et al. A 3D analysis of flight behavior of Anophelels gambiae sensu stricto malaria mosquitoes in response to human odor and heat, PLOS ONE, 2 May 2013.

add to favorites email to friend print save as pdf

Related Stories

Malaria mosquitoes accurately find their way to smelly feet

May 09, 2011

Malaria mosquitoes utilise CO2 from exhaled air to localize humans from afar. In the vicinity of their preferred host they alter their course towards the human feet. Researcher Remco Suer discovered how female malaria mo ...

Malaria mosquitoes guided by bacteria

Dec 08, 2010

The composition of our skin bacteria determines whether we are attractive to malaria mosquito. This insight should make it possible to develop an effective odor trap for mosquitoes.

New insecticide created for mosquitoes

Jul 18, 2007

French scientists have developed an effective insecticide-repellent compound that can be used against mosquitoes resistant to current chemicals.

Recommended for you

Genomes of malaria-carrying mosquitoes sequenced

8 hours ago

Nora Besansky, O'Hara Professor of Biological Sciences at the University of Notre Dame and a member of the University's Eck Institute for Global Health, has led an international team of scientists in sequencing ...

How calcium regulates mitochondrial carrier proteins

Nov 26, 2014

Mitochondrial carriers are a family of proteins that play the key role of transporting a chemically diverse range of molecules across the inner mitochondrial membrane. Mitochondrial aspartate/glutamate carriers are part of ...

Team conducts unprecedented analysis of microbial ecosystem

Nov 26, 2014

An international team of scientists from the Translational Genomics Research Institute (TGen) and The Luxembourg Centre for Systems Biomedicine (LCSB) have completed a first-of-its-kind microbial analysis of a biological ...

Students create microbe to weaken superbug

Nov 25, 2014

A team of undergraduate students from the University of Waterloo have designed a synthetic organism that may one day help doctors treat MRSA, an antibiotic-resistant superbug.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.