SEX ALLOCATION MECHANISMS IN HAPLODIPLOID HYMENOPTERANS

对单倍体锯蝇和姬蝇的性别决定和性别分配进行了研究。采用胚胎染色体技术研究了芜菁锯蝇的初次性别分配。雌性通常在10天内产下约50枚卵。一旦交配的雌性在头三天内产下许多雌性卵（雌性比例为100-70%）。第4天后雌虫比例显著下降，第7天后产卵均为雄虫。在产卵过程中，雌性在实际产卵行为之前表现出明显的腹部收缩暂停。未交配雌虫的停顿时间（平均11.3秒）比交配雌虫的停顿时间（平均4.4秒）长。在蔷薇中发现精子移位。当一只处女雌虫连续与两只处女雄虫交配时，第二只雄虫在射精前用阴茎上的锥形突起将储存在精囊中的第一只雄虫的精子取出。单对兄弟姐妹配对的细胞学证据表明，黑斑玫瑰锯蝇具有双位点CSD。两个性别位点相互独立，两个位点半合子和纯合子的个体发育为雄性，至少一个位点杂合子的个体发育为雌性。这种锯蝇的雌性在野玫瑰的幼枝上产卵。当它们在25英寸*英寸C.3处产卵时，表现出雌性-雌性-雄性的性别分配节奏。母子单对配对结果显示，鸡尾蝇具有单位点CSD。雄性二倍体形态正常，存活正常。

Sex determination and sex allocation in the haplodiploid sawflies and ichneumonfly were investigated.1. The primary sex allocation of the turnip sawfly Athalia rosae was studied by our embryo chromosome technique. Females usually lay about 50 eggs over a 10 day period. Once-mated females laid many female eggs (100-70% female ratio) within the first three days. The female ratio remarkably decreased after the fourth day, and after the seventh day, all the eggs laid were males. During an oviposition event, the females exhibit a distinct pause in abdominal contractions just before the actual egg deposition act. Unmated females showed a longer pause (11.3 s on average) than mated females (4.4 s on overall average). Sperm displacement was demonstrated in Athalia rosae. When a virgin female was mated successively with two virgin males, the second male removed the sperm of the first male stored in the spermatheca using the conical projection on the penis before ejaculation.2. Cytological evidence of brother-sister single-pair matings demonstrated two-locus CSD in the rose sawfly Arge nigrinodosa. Two sex loci are independent each other, and individuals hemizygous and homozygous for both loci develop into males and those heterozygous at least for one locus develop into females. Females of this sawfly lay egg mass in a young shoot of wild roses. They showed sex allocation rhythm such as female-female-male, when ovipositing at 25"*"C.3. Mother-son single-pair matings revealed that the ichneumonfly Coccygomimus luctuosus had single-locus CSD.The diploid males were normal in morphology and survival.