Which reproductive feature distinguishes the tsetse fly (Glossina), vector of African trypanosomiasis, from almost all other medically important dipteran vectors?
- A It lays hundreds of eggs directly on stagnant water
- B Its larvae develop inside the blood vessels of the host
- C It gives birth to a single fully formed larva at a time (larviparous) ✓
- D It reproduces by parthenogenesis without mating
Correct answer: C. It gives birth to a single fully formed larva at a time (larviparous)
Explanation
The tsetse fly exhibits adenotrophic viviparity: the egg hatches within the uterus, the larva is nourished by uterine milk glands, and the female deposits one mature third-instar larva at a time, which then burrows into soil to pupate. This very low reproductive rate means tsetse populations recover slowly after suppression. Other flies such as houseflies and mosquitoes lay large numbers of eggs, so option A describes the opposite strategy and options B and D describe mechanisms that do not occur in Glossina.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.