63.Mosquitoes - Genus Culex and genus Anopheles. Phlebotomus papatasi.

Mosquitoes (Genus Culex and Genus Anopheles)

General Morphology

• Elongated mouthparts
• Females: adapted for sucking blood
• Males: weak mouthparts
• Long 16-jointed antennae
• Wings:
• Characteristic venation
• Covered with scales
• Head:
• Spherical
• Covered with compound eyes
• Thorax:
• Rigid
• Covered by dorsal scutum
• Bears bristles and scales
• Legs:
• Three pairs
• Long and slender

Mouthparts of Female Mosquito

• Grooved lower labium
• Upper labrum-epipharynx
• Hypopharynx
• Paired stylet-like mandibles
• Serrated maxillae
• Maxillary palps:
• Slender
• Hairy
• Salivary glands:
• Located in the prothorax

Eggs

• Length: ~0.7 mm
• Enclosed in a three-layered shell
• Shell contains a funnel-shaped passage for sperm entry
• Laid on water
• Culex:
• Eggs stuck together
• Form rafts (up to ~200 eggs)
• Anopheles:
• Eggs laid singly
• Do not form rafts
• Hatching:
• Usually within 48 hours
• Some eggs survive sub-zero winters
• Water is essential for development

Larva

• Limbless
• Body bears:
• Simple or transversely branched tufted hairs
• Symmetrically arranged
• Head:
• Eyes
• Antennae
• Chewing mouthparts
• Eighth abdominal segment:
• Bears two spiracles
• Posterior end:
• Papillary processes (anal gills) for absorption
• Habitat:
• Aquatic
• Comes to surface to breathe
• Culex (culicine larvae):
• Have siphon tube
• Hang at an angle, upside down
• Anopheles larvae:
• No siphon
• Lie parallel to water surface
• Feeding:
• Microorganisms
• Organic matter in water

Pupa

• Formed from fourth instar larva
• Shape:
• Comma-shaped
• Features:
• Respiratory trumpets on thorax
• Air vesicle between future wings
• Pair of overlapping paddles with terminal hairs on last abdominal segment
• Movement:
• Paddles allow rapid diving in jerky somersaults
• Non-feeding resting stage

Adult

• Newly emerged adult rests briefly on water surface
• Wings spread and dry before flight
• Blood feeding and mating:
• Occur a few days after emergence
• Duration of stages depends on:
• Temperature
• Species

Life Cycle of Mosquito

• Eggs:
• Laid singly or in rafts
• Hatch in:
• 1–3 days at 30°C
• ~7 days at 16°C
• Larva:
• Elongated, limbless
• Passes through 4 instars
• Grows up to ~10 mm
• Larval posture:
• Anopheles – horizontal
• Culex – hanging at angle
• Pupa:
• Curved, megalocephalic, comma-shaped
• Adult emergence:
• Pupal skin ruptured by air vesicle and movement of adult