Mosquitoes

There are more than 3000 species of mosquitoes and they are found in all parts of the world, even in the Arctic.  New Zealand has 12 native species, and four introduced species.  The southern saltmarsh mosquito is a recent arrival in New Zealand.  Mosquitoes bite and can spread disease.

Life History

A mosquito's life is divided into four stages: (1) egg, (2) larva, (3) pupa, and (4) adult.  At each stage the mosquito's appearance changes completely, and the insect lives a different kind of life.

1. Eggs 
   A female mosquito lays from 100 to 300 eggs at a time.  One female may lay as many as 3000 eggs during her lifetime. The females lay their eggs near to, or on the surface of water.  All mosquito eggs must have moisture to hatch.  The eggs hatch in 2 or 3 days in warm weather.
   
   
2. Larvae
   The larva of a mosquito is often called a wriggler because it is so active. The wriggler moves about by jerking its body through the water.  A thin, skinlike shell covers its body. The wriggler has a broad head, with two short, bushy antennae. It has two eyes behind the antennae, near the back of the head. Its mouth is on the underside of the head, near the front. Long hairs called mouth brushes grow around the jaws and sweep food into the wriggler's mouth.  It eats tiny aquatic life, including one-celled organisms called protozoans, and other wrigglers.
   
   A wriggler breathes through a tube-like siphon (air tube) at the rear of its body. To get air, it pushes its siphon above the surface of the water.
   
   The larvae grow quickly. They moult (shed their skins and grow new ones) four times in 4 to 10 days. After the last moult, the larvae change into pupae.
   
   
3. Pupae
   A mosquito pupa does not eat. It changes into an adult in 2 to 4 days. The pupal "skin" splits down the back, and the adult mosquito pushes its head and front legs out. The insect then pulls out the rest of its body.
   
   
4. Adults
   After the adult mosquito leaves the pupal "skin," its wings dry quickly and it flies a short distance away. Most species of mosquito spend their whole lives within 2 kilometres of the place where they hatched. A few kinds may travel as far as 30 kilometres away to find food or mates.
   
   A female mosquito attracts a mate by the high-pitched sound made by her wings. The males are deaf for the first 24 to 48 hours of their lives, until the hairs on their antennae are dry.
   
   The females must sip blood before they can lay eggs that will hatch.
   
   Male mosquitoes may live only about 7 to 10 days, but females may live up to 30 days or more.