蝇蛹金小蜂的交配行为及雄蜂交配次数对雌蜂繁殖的影响

多数昆虫能够进行多次交配,随寄生蜂雄蜂交配次数的增加,雄蜂体内精子减少,雌蜂获得的精子数量减少,产下更多的单倍体卵,发育为雄性后代;一些单寄生性的寄生蜂雌蜂一生仅能够交配1次。描述了蝇蛹金小蜂雌雄蜂的交配行为,探讨了雄蜂交配次数对雌蜂后代产量等的影响以及雌蜂的可交配次数。结果表明,交配过程包括求偶、交尾前期、交尾和交尾后期;雄蜂已交配的次数并不能够显著影响其配偶的寿命、产卵期和后代总数量,但显著影响到其配偶的雌、雄后代数量和性比。随雄蜂交配次数的增加,与之交配的雌蜂的后代雄性百分比显著增大,雌蜂在产卵期内更早地出现较多雄性后代,体内精子不足的现象更加明显。无论已交配的蝇蛹金小蜂雌蜂在产卵期中是否出现精子不足,均不能再次完成交配。

Mating behavior of Pachycrepoideus vindemmiae and the effects of male mating times on the production of females

Most insects can mate multiple times. With the increasing of male mating frequency, male parasitoid wasps would have less sperm, and the female partners would gain less sperm during copulation, which will make them lay more unfertilized eggs, developing into male offspring. Some solitary female parasitoid wasps can only mate once in the life span. In this article, the mating behavior of the solitary endoparasitoid, Pachycrepoideus vindemmiae Rondani, was described, with the pupae of houseflies as the hosts, and the effects of male mating frequency on the production of the female partners and the possible mating times of the mated females were studied. The results showed that the mating behavior of P. vindemmiae included courtship, precopulatory, copulation, and postcopulatory, which lasts (41.21±83.16) s, (26.05±17.99) s, (2.62±0.62) s, and (30.43±11.44) s, respectively. When mated with males for the 1^st, 3^rd, 6^th, 9^th, 12^th, and 15^th times, the longevity of the females was (11.18±7.17) d, (10.82±8.51) d, (9.09±5.74) d, (9.36±4.74) d, (9.64±3.47) d, and (13.45±7.03) d, respectively, and the oviposition duration was (9.73±7.52) d, (9.82±8.51) d, (7.55±5.20) d, (8.18±4.71) d, (8.55±3.50) d, and (11.64±7.50) d, respectively. The total progeny number was (57.00±39.15), (50.18±35.52), (44.18±24.62), (42.55±15.69), (47.27±18.23), and (62.09±37.55), respectively, and the male proportion was (0.21±0.19), (0.17±0.06), (0.27±0.22), (0.43±0.31), (0.45±0.30), and (0.63±0.34), respectively. The mating frequency of males did not significantly affected longevity, oviposition duration and total progeny number of the female partners, but significantly affected the production of female and male progeny and offspring sex ratio, respectively. With the increasing of male mating times and with the increasing of female oviposition duration, daily female offspring number per foundress decreased, but male offspring number increased. When males mated for the 1^st, 3^rd, 6^th, 9^th, 12^th, and 15^th times, females laid offspring with male proportions higher than 50% on the 8^th, 17^th, 11^th, 6^th, 5^th, 2^nd day, respectively. The interaction of female ages and mating frequency affected offspring sex ratio significantly. After mated with the males which had mated multiple times, females laid more male offspring earlier, which suggests the sperm limitation in females was more obviously when they had mated with multiply mated males. Mated females could not finish mating again neither just after mating nor after they had laid eggs for 8 days, which suggests females might mate only once in their life span, no matter whether they lack sperm or not.