ENVIRONMENTAL FACTORS CONTROLLING THE EVOCATION AND TERMINATION OF DIAPAUSE IN THE FRUIT TREE RED SPIDER MITE METATETRANYCHUS ULMI KOCH (ACARINA: TETRANYCHIDAE)
ENVIRONMENTAL FACTORS CONTROLLING THE EVOCATION AND TERMINATION OF DIAPAUSE IN THE FRUIT TREE RED SPIDER MITE METATETRANYCHUS ULMI KOCH (ACARINA: TETRANYCHIDAE)
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控制果树红蜘蛛后螨（蜱螨目：叶螨科）滞育发生和终止的环境因素
DOI：
10.1111/j.1744-7348.1953.tb02387.x
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发表时间：
1953
影响因子：
2.6
通讯作者：
A. D. Lees
中科院分区：
文献类型：
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作者：
A. D. Lees
乌尔米后爪螨 (Metatetranychus ulmi) 产下两种类型的卵。夏季卵产在寄主植物（例如苹果）的叶子上，属于非滞育类型，并且不间断地发育。冬季卵主要沉积在树皮上，在胚盘发育阶段进入滞育。如果暴露在恒定的环境条件下，“夏季”和“冬季”雌性只会产下一种类型的卵。滞育是兼性的。连续七十多个夏季世代都是在防止滞育的条件下饲养的。冬季雌性出现在第一代滞育后，以响应引起滞育的刺激。
三种环境因素能够引起滞育，即光周期、温度和营养。以未受损的幼叶或成熟叶子为食的螨虫获得了充足的食物供应，滞育的发生率仅由光周期和温度决定。然而，如果食物供应受到限制，即使光周期和温度足以防止滞育，冬季雌性也会出现。当饮食由衰老叶子或先前因大量螨虫的进食刺穿而损坏的“古铜色”叶子的细胞内容物组成时，这种缺陷可能是定量的。
每日光照周期持续 6 至 13 小时，并且在中等温度（约 15°C）下，仅冬季雌性发育。滞育发生率在 15-16 小时时降至零，并且在持续光照下仅产生夏季雌虫。大约40%的夏季雌虫出现在没有光照的情况下。螨虫对光照周期的绝对持续时间做出反应，而不是对光周期的增加或减少做出反应。
如果照明超过 1-2 f.c. 的阈值，则响应与光强度无关。
光谱中近紫外、蓝色和蓝绿色区域的辐射具有光周期活性。最大灵敏度出现在蓝色区域。即使能级很高，550 m μ 以上的波长（即橙色、红色和红外区域）也完全不活跃。
螨虫直接受到光周期的影响，而不是通过寄主植物的介质间接影响。
即使光周期很短，高温（例如25°C）也倾向于防止滞育。即使光周期较长，低温（例如 10°C）也会引起一定程度的滞育。温度活动似乎主要局限于暗阶段。
发育中的螨虫对光周期、温度和营养漠不关心，直到中爪龄为止。这也是最敏感的时期，但产卵雌性如果暴露在拮抗条件下，仍然可能导致“转换”到另一种卵类型。性格中间的蛋可能会在逆转期间产下。
滞育的冬季卵在 18 或 25°C 时永远不会孵化。可以通过将卵在 1、5 或 9°C 下冷冻 150-200 天来打破滞育。
在Tetranychus telarius 中，光周期、温度和营养在控制滞育发生方面发挥着类似的作用。如果冷藏，可以导致滞育的雌性进食和产卵。热带物种Metatetranychus bioculatus没有滞育，光周期对发育没有影响。
这些实验结果已用于解释 M. ulmi 的生命周期和物候学。在整个季节螨虫数量仍然很少的果园中，第一批冬季雌螨出现在食物供应仍然充足的时候。这是通过对光周期的响应来解释的。
Metatetranychus ulmi lays eggs of two types. The summer eggs, which are laid on the leaves of the host plant (e.g. apple), are of the non-diapause type and develop without interruption. The winter eggs, which are deposited predominantly on the bark, enter diapause at the blastoderm stage of development. ‘Summer’ and ‘winter’ females lay eggs of only one type if exposed to constant environmental conditions. Diapause is facultative. Over seventy successive summer generations have been reared under diapause-preventing conditions. Winter females appear in the first post-diapause generation in response to stimuli which induce diapause.
Three environmental agencies are capable of evoking diapause, namely photoperiod, temperature and nutrition. Mites feeding upon undamaged young or mature leaves obtain a plentiful food supply and the incidence of diapause is then determined solely by photoperiod and temperature. However, if the food supplies are restricted, winter females appear even when photoperiod and temperature are such as to prevent diapause. Such deficiencies, which are probably of a quantitative nature, are manifested when the diet consists of the cell contents either of senescing leaves or of ‘bronzed’ foliage previously damaged by the feeding punctures of large mite populations.
With daily photoperiods lasting from 6 to 13 hr., and at medium temperatures (c. 15° C.), only winter females develop. The incidence of diapause falls to zero at 15–16 hr., and only summer females are produced in continuous illumination. About 40% of summer females appear in the absence of light. The mites respond to the absolute duration of the cycle of illumination and not to increasing or decreasing photoperiods.
Provided the illumination exceeds a threshold of 1–2 f.c., the response is independent of light intensity.
Radiation in the near ultra-violet, blue and blue-green regions of the spectrum is photoperiodically active. Maximum sensitivity occurs in the blue region. Wavelengths above 550 m μ, i.e. in the orange, red and infra-red regions, are totally inactive even if the energy level is high.
The mites are influenced directly by the photoperiod, not indirectly through the medium of the host plant.
High temperatures (e.g. 25° C.) tend to prevent diapause even if the photoperiod is short. Low temperatures (e.g. 10° C.) induce some diapause even with a long photoperiod. Temperature activity seems to be mainly confined to the dark phase.
Developing mites are indifferent to photoperiod, temperature and nutrition until the deutonymphal instar. This is also the period of greatest sensitivity, but egg-laying females, if exposed to antagonistic conditions, can still be caused to ‘switch-over’ to the alternative egg type. Eggs intermediate in character may be laid during the period of reversal.
Winter eggs in diapause never hatch at 18 or 25° C. Diapause can be broken by chilling the eggs at 1, 5 or 9° C. for 150–200 days.
In Tetranychus telarius photoperiod, temperature and nutrition play a similar role in controlling the onset of diapause; and females in diapause can be caused to feed and oviposit if chilled. The tropical species Metatetranychus bioculatus is without diapause and photoperiod has no influence on development.
These experimental findings have been used in an interpretation of the life cycle and phenology of M. ulmi. In orchards where mite populations remain small throughout the season the first winter females appear at a time when food supplies are still plentiful. This is accounted for by the response to photoperiod.