A Study of Winter Activities and Hibernation of Anopheles Quadrimaculatus in the Tennessee Valley

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  • Division of Malaria Studies and Control, Health and Safety Department, Tennessee Valley Authority, Wilson Dam, Alabama

Summary

  1. 1.Anopheles quadrimaculatus probably passes the winter in this latitude chiefly as inseminated adult females. No evidence of the survival of the immature stages has been discovered.
  2. 2.A fat reserve is accumulated in the autumn which gradually diminishes during the winter.
  3. 3.Hibernating females in caves may survive as long as 69 days without food.
  4. 4.The number of individuals in hibernating places reaches its maximum during the latter part of November.
  5. 5.A renewal of reproductive activity occurs early in February.
  6. 6.Autumn reared specimens survived the winter in a small outdoor cage.
  7. 7.Under artificial conditions during October, no evidence of gonotrophic dissociation was observed. The data regarding this phenomenon with reference to Anopheles quadrimaculatus is not sufficient to warrant any conclusions.
  8. 8.During November and December ovarian development appears to be deterred at temperatures below 59°F. and stimulated at temperatures of 68°F. and above. Intermediate temperatures have not been explored.
  9. 9.The temperature ranged from 51.5° to 59.°F. between December 16 and January 27 in one cave where a continuous record was kept.
  10. 10.Oocysts were discovered on the stomach of one specimen found in a cave on December 1.

Author Notes

Read before the American Society of Parasitologists, Columbus, Ohio, December 28, 1939.

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