The Female Anopheles Mosquito

by: Peters Olushola

Overview:

Contrary to conventional belief, all mosquitoes are vegetarians. They feed on nectar and fruit juice. This ideology, maybe distorting because one probably grew up associating mosquitoes with bloodsucking. Not to say one’s presumed ideology is wholly wrong, but the assumption was made by looking at one side of the painting and failing to see the entirety of the canvas.

The Anopheles species:

Sir. R. Ross (Aug 20th, 1897) found that the female Anopheles mosquito, transmitted malaria[1]. The Anopheles mosquito is popularly known as the malaria mosquito species. The Anopheles mosquito is known as the transmitter of heartworms in dogs. There are 430 species of the Anopheles genus of mosquitoes, and out of them, only about 30 – 40 are vectors of malaria. Many of the Anopheles species have developed resistance to insecticides over the years and are known to be active during the hours of dawn and dusk. The Anopheles mosquito can be found anywhere in the world excluding Antarctica.

The female Anopheles mosquito and blood:

Anytime one gets pricked by a mosquito; it happens because the female mosquito needs the human blood, to nourish its eggs. On average, the female Anopheles mosquito lays 50 – 200  eggs within a sperm 2 – 3 days. It is worthy to note that a female Anopheles mosquito can suck blood up to 3 times its weight and to completely drain human blood, the mosquito would need to bite the human for about 1.2 million times.

The piercing action of the Anopheles mosquito:

The stinging feeling you experience when a mosquito is on one’s skin is the mosquito piercing its Proboscis through the skin. At the end of this proboscis are two slender cutting Stylets. These Stylets slide against each other and slices through the skin. Once they have sliced through the human-skin, the mosquito begins to probe for tiny blood vessels with its proboscis, and if the mosquito does not find a blood vessel on its first try, the mosquito will pull up slightly try again. When the mosquito successfully hits a blood vessel, it begins the extraction of human – blood. Inside the proboscis are two hollow tubes: one that injects saliva into the wound and the other that sucks blood. The mosquito’s saliva is a combination of anti-hemostatic and anti-inflammatory enzymes. The anti-hemostatic enzyme prevents blood clotting during the sucking action, and the anti-inflammatory enzyme inhibits the pain reaction thus making the victim unaware of the piercing.

Breeding habitats of the Anopheles mosquito:

Certain habitats are very conducive and aid breeding for the female Anopheles mosquito. The Anopheles mosquito breeds in any natural water selection. This implies that their reproduction increases exponentially during the raining season. The storage of water in broken bottles, basins, coconut shells, buckets, drainages, tires, cans, etc. provides ample breeding place for the mosquito. It is essential to take note of anything in one’s surrounding that holds a pool of water and destroy or cover them to prevent mosquito breeding. On average a mosquito’s lifespan is between 2 – 3 weeks. Although in ideal living conditions some mosquitoes can live longer.

The Anopheles mosquito goes through 4 stages in its lifecycle which are:

Egg stage:

At this stage, the female mosquito lays about 50 – 200 eggs per oviposition. The eggs are laid singly on a water surface and remain on the surface through the aid of floats they have on each side. The eggs hatch between 2 – 3 days depending on weather conditions.

Larva stage:

At this stage, the larva is developed after the egg hatches. A developed head has a mouth brushes which it uses for feeding. The larva also has a large thorax and a segmented abdomen. The larva has no legs and respiratory siphon; thus they breathe through spiracles located on the 8th abdominal segment, so they have to come to the surface of the water frequently for breathing. They feed on algae, bacteria and other microorganisms. Their jerky motion is achieved through propulsion which is aided by their mouth brushes. The larva goes through 4 stages or instars before they metamorphose into a pupa.

Pupa stage:

When viewed from the side, the pupa looks like a comma. At this stage, the head and thorax of the larva are merged to form cephalothorax with the abdomen curving around the underneath. The pupa also has no respiratory siphon, and it breathes through a pair of respiratory trumpets on the cephalothorax. They have to come to the surface of the water to breathe frequently.  After a few days, the dorsal cephalothorax of the pupa splits, and adult mosquito emerges. The egg stage, though the pupa stage occurs in water.

Adult stage:

This is the development stage we all are familiar with as this stage does not occur in water. The adult mosquito is characterized by a slender body and having three sections: head thorax and abdomen. The head is adapted for acquiring sensory information and feeding. The head contains the eyes and many-segmented antennae which are used for detecting host odors. The head has an elongated-forward-projecting proboscis which it uses for feeding. The life cycle of a mosquito from egg to adult is about five days on average under ideal conditions. However, in the tropics, this cycle usually takes 10 – 14 days.

References

  • Malaria Site: Anopheles mosquito

https://www.malariasite.com/anopheles-mosquito/ 

  • Slide share: Anopheles

https://www.slideshare.net/ontolapata/anopheles 

  • SHASTA MVCD: Mosquito biology

https://www.shastamosquito.org/mosquito-biology 

  • Mosquito Magnet: Anopheles mosquito

http://www.mosquitomagnet.com/advice/mosquito-info/biting-insect-library/anopheles-mosquito 

  • Mega-Catch: Mosquito facts- 33 things you didn’t know about mosquitoes

https://www.megacatch.com/mosquito-faqs/mosquito-facts.html


[1] https://www.cdc.gov/malaria/about/history/ross.html