State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
USDA-Agricultural Research Service, Corn Insects and Crop Genetics Research Unit, 503 Science Hall II, 2310 Pammel Drive, Ames, IA 50011, USA.
Environ Entomol. 2021 Jun 18;50(3):523-531. doi: 10.1093/ee/nvab015.
A facultative commitment to adult migration in the larval stage can be modified again after adult emergence in some Lepidoptera when influenced by an appropriate environmental cue during a sensitive stage. This phenomenon is termed secondary regulation of migration. The sensitive stage in adult beet webworm, Loxostege sticticalis L. (Lepidoptera: Pyralidae), was determined experimentally by starvation of presumed migrant females reared from gregarious-phase larvae (induced by crowding at 10 larvae per 650-ml jar). When presumed migrant adults were starved for 24 h on either of the first 2 d after emergence, the preoviposition period was shortened. In contrast, preoviposition periods were not significantly shortened for migrants starved on day 3 or when starvation lasted for more than 1 d after emergence. Because the preoviposition period corresponds to the migratory period in beet webworm, the results suggest that the first 2 d of adult life in the beet webworm is the sensitive stage during which presumed migrants can be switched to residents by an appropriate environmental cue. During the sensitive stage or not, starvation did not influence lifetime fecundity, oviposition period, longevity, or hatching rate of eggs laid by the starvation-stressed moths. Starvation on the first day also increased tethered flight performance and accelerated both flight muscle and ovarian development. The results suggest that a pulse of starvation in the sensitive period may inhibit the expected migration by accelerating and compressing the cycle of migratory flight muscle development and degeneration, while accelerating ovarian development, which is normally suppressed until after migration.
在某些鳞翅目昆虫中，幼虫期的成虫迁徙是一种兼性的承诺，在适当的环境线索影响下，在成虫出现后仍可以再次改变，这种现象被称为迁徙的二次调节。通过在拥挤的条件下（每 650 毫升罐中 10 条幼虫）饲养群居期幼虫来诱导，实验确定了甜菜夜蛾（鳞翅目：夜蛾科）成虫的敏感阶段。当假定的迁徙成虫在出现后的前 2 天中的任何 1 天被饥饿 24 小时时，产卵前期缩短。相比之下，当在出现后的第 3 天或饥饿持续超过 1 天时饥饿的迁徙者，产卵前期没有明显缩短。由于产卵前期对应于甜菜夜蛾的迁徙期，因此结果表明，甜菜夜蛾成虫生活的前 2 天是敏感阶段，在此期间，适当的环境线索可以将假定的迁徙者转换为定居者。在敏感阶段或不在敏感阶段，饥饿都不会影响寿命、产卵期、成虫寿命或饥饿胁迫的雌蛾所产卵的孵化率。第一天的饥饿也增加了系留飞行性能，并加速了飞行肌肉和卵巢的发育。结果表明，敏感时期的短暂饥饿可能通过加速和压缩迁徙性飞行肌肉发育和退化的周期来抑制预期的迁徙，同时加速通常在迁徙后才被抑制的卵巢发育。
