类寄生虫黄蜂中的Haplo-二倍体性别确定,纳西尼亚·硫酸尼斯(沃克),允许女性调整其育龄性别比例。雌性影响卵子是否受精,产生二倍体雌性,或者保持未受精,产生单倍体雄性。雌性似乎调整了它们的育龄性别比例,以最大限度地减少当地的伴侣竞争,\'即,儿子之间的竞争。因为交配发生在兄弟姐妹之间,雌性可以通过在单独产卵时只生产足够的儿子来授精女儿来优化后代的交配机会,并在可能出现超寄生现象时生产更多的儿子。虽然被广泛接受,这一假设对任何性别的配子限制都没有假设。因为精子是用来生女儿的,反复产卵会减少精子供应,使女性生更多的儿子。相比之下,如果受卵限制的雌性产生较小的育苗,他们可能会使用更少的精子,使精子限制的可能性降低。为了调查重复产卵和女性生育能力是否影响女性配子限制,我们对六个交配的雌性黄蜂进行了两种治疗,每个人每隔24或48小时接受一系列六个寄主。所有雌性至少产生一个混合性别育苗(总共63个育苗;3,696个后代)。不出所料,如果雌性变得精子受限,在两种治疗中,随着宿主数量的增加,育龄性别比变得越来越偏向男性。宿主间隔时间不影响育苗大小,后代总数,或者性别比例,表明雌性没有受卵限制。我们的结果支持早期的研究,这些研究表明精子耗竭会影响硫酸黄蜂的性别分配,并可能限制这些类寄生虫黄蜂的适应性性别比操纵。
Haplo-diploid sex determination in the parasitoid wasp, Nasonia vitripennis (Walker), allows females to adjust their brood sex ratios. Females influence whether ova are fertilized, producing diploid females, or remain unfertilized, producing haploid males. Females appear to adjust their brood sex ratios to minimize \'local mate competition,\' i.e., competition among sons for mates. Because mating occurs between siblings, females may optimize mating opportunities for their offspring by producing only enough sons to inseminate daughters when ovipositing alone, and producing more sons when superparasitism is likely. Although widely accepted, this hypothesis makes no assumptions about gamete limitation in either sex. Because sperm are used to produce daughters, repeated oviposition could reduce sperm supplies, causing females to produce more sons. In contrast, if egg-limited females produce smaller broods, they might use fewer sperm, making sperm limitation less likely. To investigate whether repeated oviposition and female fertility influence gamete limitation within females, we created two treatments of six mated female wasps, which each received a series of six hosts at intervals of 24 or 48 h. All females produced at least one mixed-sex brood (63 total broods; 3,696 offspring). As expected, if females became sperm-limited, in both treatments, brood sex ratios became increasingly male-biased with increasing host number. Interhost interval did not affect brood size, total offspring number, or sex ratio, indicating females did not become egg limited. Our results support earlier studies showing sperm depletion affects sex allocation in N. vitripennis¸ and could limit adaptive sex ratio manipulation in these parasitoid wasps.