贵州赤水桫椤叶蜂的生物学特性及其幼虫种群发生现状分析

桫椤叶蜂Rhoptroceros cyatheae（Wei et Wang，1995）是目前已知取食桫椤Alsophila spinulosa（Wall.ex Hook.）Tryon的食叶害虫，对桫椤的生长发育和繁殖造成了一定的影响。通过人工饲养观察和野外调查相结合，对桫椤叶蜂的生物学特性和发生动态进行了调查和分析。结果表明，桫椤叶蜂在赤水一年发生四代，以老熟幼虫越冬，越冬期长达5个月，翌年4月上旬成虫开始羽化，产卵于卷曲叶或是刚舒展的嫩叶表面，幼虫主要取食桫椤嫩叶，第一、二代幼虫种群数量较大；幼虫只蜕四次皮，虫龄为五龄。调查发现了桫椤叶蜂幼虫不只取食桫椤还可取食小黑桫椤Alsophila metteniana叶片，还确定了长角髭寄蝇Vibrissina turrita为桫椤叶蜂的寄生天敌。闷头溪、金沙站、佛光岩和大水沟1四个采集点的幼虫种群数量明显高于其他采集点，且种群动态较为稳定，可作为桫椤虫害防控的重要监测区域。本文进一步明确了桫椤叶蜂的生活习性及发生规律，为后期的调查研究和虫害防控提供科学有效的支撑依据。

Biological Characteristics and Larval Population Dynamics of Rhoptroceros cyatheae in Chishui Guizhou

Rhoptroceros cyatheae,a known leaf-eating pest of Alsophila spinulosa,affects growth,development and reproduction of the host plant.The biological characteristics and occurrence dynamics of R.cyatheae were investigated and analyzed by means of artificial rearing,observation and field investigation.R.cyatheae occurs 4 generations annually in Chishui,overwinters as mature larvae for 5 months,and adult emergence begins in early April in the following year.Eggs are laid on the surface of curled leaves or newly stretched young leaves.Larvae mainly feed on the young leaves of A.spinulosa,and the population size of the 1st and 2nd generations is relatively large.The larvae molt four times,and there are five instars.Except for leaves of A.spinulosa,larvae of R.cyatheae feed also on the leaves of Alsophila metteniana.Vibrissina turrita was identified as the parasitic natural enemy of R.cyatheae.The larval population at Mentouxi,Jinsha Station,Foguangyan and Dashuigou 1 was higher than that at other sites and relatively stable,thus the four sites can serve as the monitoring areas for pest control of A.spinulosa.The biological characteristics and population dynamics of R.cyatheae clarified in this study can provide effective support for future investigation and pest control of A.spinulosa.