豚草卷蛾对温湿度的适应性

Adaptability of Epiblema strenuana to Temperature and Humidity Conditions

对豚草卷蛾温湿度的适应性作了研究。结果表明,豚草卷蛾的过冷却点在-6 84～-15 84℃之间,随入冬气温的逐渐降低而降低,越冬滞育幼虫的含水量明显低于生长期幼虫。在35℃高温条件下,发育期虫态的化蛹率为27.3%,其存活率、孵化率、正常羽化率和成虫的交配率在50 0%～68 4%之间,产卵量仅为87 6粒/♀,表明35℃已是豚草卷蛾生长发育的限制温度。在高温处理下各虫态50%个体死亡所需时间依次为成虫>幼虫>卵>蛹,以蛹的死亡历期最短。各虫态在不同湿度环境下以成虫产卵所受的影响较小。附着在新鲜叶片上的卵几乎不受环境湿度的影响。化蛹和羽化要求环境湿度在80%以上。

Epiblema strenuana is an important biocontrol agent imported to China in 1990 to control Ambrosia artemisiifolia. In 1991 this insect was released in Hunan province, and now has been established there. In order to evaluate its potential distribution in China, its adaptability to the temperature and humidity was investigated under laboratory condition. The results showed that larval supercooling points ranged from -6.84℃ to -15.84℃, which changed with season. Supercooling points of diapaused larvae in winter were significantly lower than developing larvae in summer. Icing points of larvae had a similar changing profile with supercooling. The moisture content of diapaused larva was also significantly lower than developing larva. At 35℃, pupation rate was 27.3%, egg hatching rate 68.4%, emergence rate 50.0%, and mating rate 51.3%. It was showed that 35℃ was the upper threshold temperature for the development. Pupa was the most susceptible stage, followed by egg, larva and adult, to high temperature regimes. Fecundity was little influenced by humidity compared with other growing stage. When adhered to fresh leaf, egg could hatch under very dry condition. Pupation and emergence need relative humidity of over 80%.