In this article we will discuss about the life cycle of Culex with the help of a diagram.
Fig. 253 CULEX LIFE CYCLE
The Life Cycle of Culex has following three stages:
The Eggs:
1. They are laid in rafts of about 300 eggs held, together through sticky substance for floating along the surface of water.
2. The eggs are brownish in colour and some what oval in shape.
3. They contain air bubbles trapped in the sticky substance to provide buoyancy.
4. They hatch after 24-48 hours into free swimming larvae.
The Larvae:
1. They are the first free swimming stages in the life cycle.
2. The larva lies at an angle to the surface of water in resting condition.
3. The body is elongated and some what cylindrical and is divisible into head, thorax and abdomen.
4. The head bears paired antennae, eyes, feeding brushes and mandibulate mouth parts.
5 Thorax is broad, un-segmented and bears tufts of hair for wriggling in water.
6. Abdomen is without palmate hairs.
7. The 8th segment bears a long tubular respiratory siphon at the tip of which lies a spiracle.
8. Ninth segment bears two pairs of tracheal gills and two tufts.
9. It hatches out into pupa after 4 moultings.
The Pupa:
1. The pupa develops from larva after seven days.
2. The body is comma shaped (,) and is covered over with a transparent puparium.
3. In pupa the head and thorax have united into cephalothorax which has become greatly distended and bears paired short respiratory siphons, compound eyes, long and jointed antennae and rudiments of appendages.
4. The abdomen is long, 9 segmented and curved but not flexed below cephalothorax. It, however, bears a pair of paddles & a pair of tracheal gills attached to ninth segment and palmate hairs on all segments.
5. It metamorphoses into adult after a short free swimming life.