异色瓢虫两个单倍体基因型的生物学特性比较

Comparison in Life History Traits of Two Haplotypes in Harmonia axyridis(Coleoptera: Coccinellidae)

单倍体基因型(单倍型)与表型的关系是认识物种适应分化的重要依据。异色瓢虫Harmonia axyridis(Pallas)有多种单倍型,我们从南京地区的种群中发现两种优势单倍型(I型和II型),且这两种单倍型在自然界中数量差异较大。为了探究这两个优势单倍型异色瓢虫生物学特性的差异,在室内条件下以豌豆修尾蚜Megoura japonica(Matsumura)为食物,观察这两个单倍型的幼虫期死亡率和发育历期、雌成虫终身产卵量和卵孵化率等生物学参数。结果表明,单倍型-I和单倍型-II的幼虫发育历期差异显著,分别为14.38和13.75 d;单倍型-I在幼虫各龄期的死亡率均低于单倍型-II,分别为13.33%和29.20%(1龄)、5.49%和13.75%(2龄)、1.16%和4.35%(3龄)、2.35%和10.61%(4龄)。单倍型-I和单倍型-II的成虫终身产卵量无显著差异,分别为936粒和887粒;卵孵化率差异显著,单倍型-I的卵孵化率(64.53%)高于单倍型-II(60.99%)。综合来看,异色瓢虫的两个单倍型在自然界存在数量差异的原因可能是其在生殖和发育上的差异造成的。

Connecting genotypes and phenotypes improves our understanding of evolution of the organism.Harmonia axyridis has a variety of haplotypes,among the haplotypes presented in H.axyridis,we screened two dominant haplotypes(I and II)from the population of Nanjing with asymmetric number in natural condition.In order to explore the differences in the biological characteristics of these two dominant haplotypes,we observed the developmental and reproductive performances from egg-hatching to adulthood of these two haplotypes while feeding on the aphid Megoura japonica(Matsumura)under laboratory conditions.The results indicated that the larval developmental duration of haplotype-I and haplotype-II was significantly different,which was on average 14.38 d for Haplotype-I and 13.75 d for Haplotype-II.Haplotype-I was lower than Haplotype-II in survivorship across successive larval stages,13.33%and 29.20%for L1,5.49%and 13.75%for L2,1.16%and 4.35%for L3,and 2.35%and 10.61%for L4,respectively.The two haplotypes did not differ in female lifetime fecundity,which was on average 936 eggs per female for Haplotype-I and 887 for Haplotype-II.Haplotype-I was higher than Haplotype-II in hatching rate of eggs,64.53%for the former and 60.99%for the later.Overall,the difference in the number of two haplotypes of the H.axyridis in nature probably be due to differences in reproduction and development.