【摘要】 本文报导了几种相对湿度下25—46℃高温对粘虫卵发育与孵化的作用。卵发育及孵化的适温上限为31.0-32.5℃,其致死高温限为32.0-33.5℃。在25.0—32.0℃间,孵化率不因温度而有显著变化,发育速率则随温度升高而加快:湿度仅在大幅度下降时才对孵化率有显著影响,但对发育速率的影响则随温度增高而加大,在接近适温上限时湿度又成为决定卵发育与孵化的主要因素。高温的致死作用,因温度强度、处理时间及相对湿度而异。温度越高,忍受时间越短,41℃以上高温处理2小时,即使绝大部分卵死亡。高温下饱和湿度,对卵的发育与孵化不利。受精卵处于第一步分裂前期,抗高温能力较差。温度驯化略可提高卵的耐高温能力。文中还讨论了高温致死的原因及湿度的作用。更多还原

【Abstract】 The present paper deals with the effect of high temperatures on the developmentand hatching of the eggs of the armyworm, Leucania separata Walk., at various relativehumidities. Results of the experiments may be summarised as follows: 1. Within the range of constant temperatures between 25--32℃, the percentagesof hatching are all above 90%, except those in relative humidity 22%. The percent-ages of hatching are not affected significantly by changing temperature, but are slightlyaffected by the change in relative humidity; the percentage of hatching decreases as therelative humidity decreases. When the relative humidity falls to 22%, its effect is mostsignificant. Under a very low relative humidity the decrease of the percentage of hatch-ing is probably due to the loss of water from the eggs. The rate of development ofeggs is accelerated as the temperature rises, but it is retarded as the relative humidityfalls. The effect of relative humidity on the rate of development increases as the tem-perature rises probably due to the rapid water evaporation in the low relative humidityat high temperatures. The increase in the rate of development is relatively great between25--29℃. At relative humidity above 60%, the egg development is at 32℃. 2. The upper limit of the optimal range of temperature for the development of theeggs is approximately at 31.0--32.5℃, while the lethal high temperature, taking LD₅₀ asthe standard, begins at 32.0--33.5℃ in accordance with proper relative humidity. Whenthe relative humidity is below 63%, the limit will be at 32.0--33.0℃; and when therelative humidity goes above 63%, it lies at 33.0--33.5℃. Out of this limit, both thepercentage of hatching and the rate of development decrease rapidly. 3. At 35--41℃ constant temperatures, eggs are unable to hatch, but embryonicdevelopment goes on to various extents. The percentage of embryos able to proceed tothe larval form decreases wth the rise in temperature and the increase of exposing time,but increases slightly with falling relative humidity. At lethal high temperatures, satu-rated humidity becomes unfavorable for embryonic development. 4. The lethal effect of high temperatures on the eggs is the result of temperatureintensity and time of exposure; the higher the temperature, the shorter the time eggs canstand the situation. Between 37--39℃, there exists a sharp decline in the exposing time.The time for endurance at 37℃ is 9 times that at 39℃. This may be due to the rup-ture of the wax-layer in the egg chorion, which allows water to evaporate rapidly. Sincea short period （2 hrs.） of exposure to temperatures above 41℃ will cause a mortalityabove 95%, these temperatures may be regarded as the absolute lethal high temperatures. 5. Eggs that are at the stage prior to first zygotic division are less resistant to heatthan those that have their embryos with mid-gut and mouth-piece formed. Acclimatiza-tion to high temperature may increase the ability of resistance to lethal high temperature.The effect of lethal high temperatures on early embryos exhibits an after-effect.更多还原