Lifecycle

LIFECYCLE - OX WARBLE FLIES
  • The adult fly does not feed and only oviposits on the cattle – usually the lower regions of the hind legs, hence the common name ‘heel fly’
  • A fly oviposits atleast 6 eggs towards the base of the hair of the cattle during the summer months 
  • The eggs are spindle shaped and provided with a clasper with the help of which they hold on to the hair 
  • The egg hatches in 3-4 days 
  • The first stage larvae pierces through the skin and migrates in the intermuscular connective tissues to reach the diaphragm 
  • Most larvae reach the tissues of the oesophagus in 4 months time and spend the winter in the submucosal connective tissue of the oesophagus- hence the site is referred to as the winter resting site
  • The first stage larvae moults to form the second stage larvae which in the beginning of spring, i.e., January migrate towards the dorsal aspect of the body, reaches the subcutaneous tissue of the back and moults to the third stage 
  • The back of the animal is hence referred to as spring resting site
  • When the larvae reach the skin of the back an inflammatory reaction results in the formation of sweliings 
  • The second stage larvae perforates the swelling 
  • It then moults and the third stage larvae lies upside down with the posterior spiracle directed against the perforation 
  • The mature larvae has no oral hooks and feeds on the inflammatory exudates in the swelling.  These swellings in the skin of the cattle are referred to as warbles
  • The warble stage lasts for 30 days 
  • It falls off the warble into the soil and pupates 
  • Pupation take 1 month time
  • Entire lifecycle is completed in one year
Last modified: Saturday, 7 August 2010, 6:27 AM