遗传和环境因素对曲脉姬蟋亚热带种群翅型分化的影响

Effects of genetic and environmental factors on wing dimorphism in a subtropical population of Modicogryllus confirmatus Walker

曲脉姬蟋Modicogryllus confirmatus Walker具有明显的翅二型现象。为探究环境及遗传如何影响曲脉姬蟋亚热带种群的翅型分化,对饲养于不同光周期、温度和密度条件下若虫羽化后的翅型比进行了调查,并对长、短翅型蟋蟀进行了3代遗传筛选和杂交试验,研究了光周期、温度、种群密度和遗传对曲脉姬蟋广西种群翅型分化的影响。结果表明:光周期和种群密度对曲脉姬蟋的翅型分化均无影响,而温度对其翅型分化具有调控作用。正常范围内的温度变化(25℃、30℃)对其翅型分化无显著影响,而35℃的极高温则显著降低曲脉姬蟋的长翅率,说明其翅型分化并不是对季节变化的适应,而高温胁迫可引起短翅化。对不同翅型进行了3代筛选,结果表明,往短翅型选拔会引起雌、雄虫的短翅率都明显下降,而往长翅型选拔时,雌、雄虫的短翅率均维持在极低水平;不同亲本组合的后代间的长翅率有差异,说明曲脉姬蟋的翅型分化可能受多基因调控。

The cricket species Modicogryllus confirmatus Walker displays distinct wing dimorphism. In this paper, effects of photoperiod, temperature, density, and heritability on wing differentiation in a subtropical population of M. confirmatus were studied in order to find out possible relationship between wing development and environmental and genetic factors. The results showed that neither constant photoperiod nor changing photoperiod could influence its wing differentiation. The macropterous rate did not change significantly when nymphs were reared under 25 ℃ and 30 ℃, but it decreased significantly when nymphs were kept under exceeding high temperature （35 ℃）. These results indicate that seasonal adaption may not be the reason of wing differentiation of M. confirmatus, but high temperature stress may have a strong micropters inducing effect. The macropterous rate also did not change significantly when nymphs were kept under different density suggesting the density could not affect the wing differentiation too. After selection for 3 generations the frequency of micropters in a SW selected line increased significantly, whereas it remained at a low level in a LW selected line. Crossing experiments indicated that wing morph was under polygenetic control.