SPERM TRANSFER AND STORAGE IN THE MEDITERRANEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE)

We examined several aspects of sperm transfer and storage in the Medit erranean fruit fly, Ceratitis capitata (Wiedemann). We determined how many sperm are available to virgin males, how many sperm they ejaculat e, and how many are subsequently stored by females. In addition we est ablished how sperm are allocated between the 2 spermathecae and invest igated sperm load and sperm allocation patterns in females captured in the field in Israel. Males testes contained on average 34,300 +/- 2,5 00 sperm cells before copulation and 14,759 +/- 1,400 after copulation . Intriguingly, most of this ejaculate never reaches the spermathecae. Spermathecae of once-mated laboratory reared females contained 3,212 +/- 212 sperm, similar to the amount found in field-collected females, 3,612 +/- 237. Continuous access to males in the laboratory resulted in significantly elevated numbers of stored sperm (on average 5,250 +/ - 790). indicating that multiple mating is common. The abundance of sp erm stored by field-collected females supports this conclusion. Sperm allocation between the spermathecae, in both field and laboratory fema les, is significantly nonrandom; one organ (either left or right) cont ains significantly more sperm than expected by chance, suggesting that allocation of sperm is controlled, either by the male or by the femal e.