STUDIES ON SPERMATHECAL FILLING IN AEDES AEGYPTI (LINNAEUS). II. EXPERIMENTAL

Abstract

1. Spermathecal filling in Aedes aegypti is not affected by changing the orientation of the intact female's terminalium.2. Crushing the head of the female before forced-copulation tends to interfere with coitus. Decapitation of the female before forced-mating may lead to prolonged coitus but this does not necessarily result in insemination or spermathecal filling.3. Crushing the head of the female during the act of forced-copulation does not interfere with coitus, insemination, or spermathecal filling. Crushing of the female's head immediately after coitus does not interfere with spermathecal filling.4. Spermathecal filling can occur when the freshly inseminated female's terminalium is cut off into a drop of saline.5. On a few occasions, spermathecae have been seen to fill with sperm in oilcovered saline whole mounts of the isolated reproductive system of a freshly inseminated female.6. Sperm can ascend to the thecae during the time of oviposition, presumably between the intervals of egg depositions.7. Spermathecal filling can occur in females which are externally immobilized by exposure to nitrogen, ether, carbon dioxide and cyclopropane.8. Submerging freshly inseminated females in an ice bath at 40° to 7° C. for 10 to 30 minutes did not prevent spermathecal filling; at these temperatures the sperm are generally quite active. At 1° to 2° C., however, spermathecal filling is inhibited; at such temperatures sperm activity is greatly reduced or abolished.9. Male Aedes can copulate with dead females and may deposit active sperm in the bursa but spermathecal filling does not occur.10. Dyes injected only into the bursae of virgin females may be transported to one, two, or all three thecae, and to the common oviduct as far as the ampullae. But, dyes injected into the bursae of inseminated females are not transported to the thecae.11. When seminal vesicle sperm with or without additives was injected into the bursa, only a few sperm reached the large theca in 13 (18.3%) of 71 cases.12. When fresh ejaculates from donor bursae were injected into recipient virgin bursae, considerably better results were obtained in some cases and the sperm reached one or two thecae in 5 (35.7%) out of 14 cases.13. The female is incapable of transporting dead sperm to her spermathecae. Highly active and oriented sperm artificially injected into the bursa generally do not fill the spermathecae.14. The behavior of the sperm alone is not capable of explaining normal spermathecal filling. The role of the female during spermathecal filling is not clear.