Brent Colin S, Spurgeon Dale W
Pest Management and Biocontrol Research Unit, USDA, ARS, ALARC, Maricopa, AZ.
J Insect Sci. 2019 May 1;19(3). doi: 10.1093/jisesa/iez066.
As water for agriculture becomes less available in the semi-arid western United States, alternative irrigation strategies such as deficit irrigation may be necessary for continued crop production. Alternative irrigation practices in cotton (Gossypium spp. [Malvales: Valvaceae]) can result in episodic drought stress that alters temperature profiles within the crop canopy. These altered temperatures may influence populations of important pests such as Lygus hesperus Knight. Field studies often associate lower population densities of L. hesperus with limited irrigation. Recent studies of the thermal ecology of L. hesperus egg and nymphal development have demonstrated only subtle effects of the high, variable temperatures typical of moderate drought stress in cotton. However, influences of these conditions on L. hesperus adult reproductive development have not been studied. The reproductive development of L. hesperus adults was examined under constant (±0.2°C) and variable (±8°C) regimes at a low (15°C), moderate (22°C), and high (29°C) daily mean temperatures. No developmental differences were demonstrated between temperature regimes under moderate or high temperatures. At the low temperature, only the times to the occurrence of eggs, filled medial accessory glands, and filling seminal vesicles were shorter under variable regime, compared with the constant temperature. These results suggest that temporary, episodic increases in crop canopy temperatures caused by moderate drought stress are unlikely to impact L. hesperus population growth, and may only promote short-term displacement of adults into adjacent crops with preferable conditions.
在美国西部半干旱地区，农业用水日益匮乏，因此可能需要采用亏缺灌溉等替代灌溉策略来维持作物产量。棉花（棉属[锦葵目：锦葵科]）采用替代灌溉方式可能会导致间歇性干旱胁迫，从而改变作物冠层内的温度分布。这些变化的温度可能会影响重要害虫如西方盲蝽的种群数量。田间研究常常将西方盲蝽较低的种群密度与有限灌溉联系起来。近期对西方盲蝽卵和若虫发育热生态学的研究表明，棉花中度干旱胁迫典型的高温、多变温度只会产生细微影响。然而，这些条件对西方盲蝽成虫生殖发育的影响尚未得到研究。在日平均温度低（15℃）、中（22℃）、高（29℃）的情况下，分别在恒定（±0.2℃）和可变（±8℃）温度条件下研究了西方盲蝽成虫的生殖发育。在中度或高温条件下，不同温度条件之间未表现出发育差异。在低温条件下，与恒温相比，只有在可变温度条件下，产卵、中侧副腺充满和精囊充满的时间更短。这些结果表明，中度干旱胁迫导致的作物冠层温度暂时、间歇性升高不太可能影响西方盲蝽种群增长，可能只会促使成虫短期迁移到条件更适宜的相邻作物中。
