Sperm storage and the fertile period in the Bengalese Finch-猫眼课题宝

孟加拉雀的精子储存和受孕期

DOI：

发表时间：

1992

期刊：

The Auk

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

T. Birkhead

-Female Bengalese Finches (Lonchura striata) stored sperm in sperm storage tubules and were capable of producing fertile eggs for a median of 8 days (maximum 16 days) following the last copulation. The age of stored sperm had no effect on the hatching success of eggs. More sperm were present in a female's sperm storage tubules after copulation that occurred before ovulation than after one that occurred after ovulation. On average only about 1% of the sperm transferred during copulation were stored in the sperm storage tubules. Similar "selection" of sperm in the female reproductive tract has been recorded in other vertebrates. Its mechanism and functional significance are discussed. Received 31 May 1991, accepted 19 February 1992. FEMALE BIRDS are known to store sperm for days or weeks following copulation or artificial insemination, prior to using it to fertilize their eggs (Howarth 1974, Birkhead 1988). Sperm storage probably evolved primarily because in birds ovulation, fertilization and oviposition occur sequentially and each egg is fertilized separately during a very short period (< 30 min) following ovulation. Without sperm storage, copulation would have to occur immediately prior to each ovulation. In species laying multiple-egg clutches the duration of sperm storage is positively correlated with the number of days over which egg laying occurs (Birkhead and M0ller 1992a). In species that produce only a single-egg clutch, such as many seabirds, sperm storage allows females to forage away from their partner for prolonged periods of unpredictable duration prior to egg laying and still ensure fertilization (Imber 1976, Hatch 1983, Birkhead and M0ller 1992a). A further explanation for sperm storage in birds is that it allows a population of sperm to be "selected" from those inseminated (Bakst and Bird 1987). The fertile period is the period during which a copulation potentially can fertilize one or more eggs (Lake 1975). The fertile period is determined by the duration of sperm storage and the spread of laying (i.e. clutch size multiplied by the interval between successive eggs; Birkhead 1988). A prolonged fertile period enhances the opportunities for sperm competition because it increases the likelihood of ejaculates from different males overlapping (Parker 1970). As several recent studies have shown, sperm competition among birds is widespread, despite monogamy being the predominant mating system (Birkhead et al. 1987, Westneat et al. 1990, Birkhead and M0ller 1992b). The duration of sperm storage and, hence, the fertile period is known for relatively few birds, mainly domesticated species (for review, see Birkhead and M0ller 1992a) and in detail for only a single passerine, the Zebra Finch (Taeniopygia guttata; Birkhead et al. 1989). The mean or median sperm-storage duration in birds varies from 6 to 45 days (Birkhead and M0ller 1992a). The aim of the present study was to determine the duration of the fertile period in another passerine, the Bengalese Finch (Lonchura striata), for comparison. In addition, some aspects of the mechanism of sperm storage were investigated by examining the pattern of sperm uptake by the sperm storage tubules (referred to hereafter as SSTs; Birkhead and Hunter 1990, Birkhead et al. 1990).