萧氏松茎象的生活史、产卵和取食习性

萧氏松茎象Hylobitelus xiaoi是严重蛀害国外松的新害虫。在江西赣南地区两年发生一代，以幼虫在蛀道、成虫在蛹室或土中越冬。卵和蛹的发育起点温度分别为8.4℃和7.5℃，有效积温分别为215.9和345.3日·度。各虫态历期：13～28℃间，卵为52.9～11.4天；13～30℃间，蛹为60.1～16.4天； 25℃恒温下，幼虫128.9天。成虫靠爬行活动，极少飞翔。成虫具夜出性活动节律：即傍晚上树行取食、交配和扩散等活动，早晨回到树干基部或土缝中。成虫需取食松枝作为补充营养，产卵前期46.3天，产卵期 105.3天，卵产于近表土的寄主树皮内，每雌产卵35.7粒。幼虫5～7龄，以幼树危害最烈。

Life history,oviposition and feeding behavior of Hylobitelus xiaoi Zhang ( Coleoptera:Curculionidae)

Hylobitelus xiaoi Zhang is a newly breaking out pest attacking exotic pines with larvae feeding on the inner bark of both lower parts of tree trunks and root collar area. This species required two years to complete one generation in southern Jiangxi, with overwintering by adults in pupal chambers and soil and by larvae in galleries in the bark of host trees. Thermal threshold for development was 8.4℃ for egg and 7.5℃ for pupa. Thermal sum for development was 215.9 day-degrees for egg and 345.3 day-degrees for pupa. Between 13－28℃, the developmental duration was 52.9－11.4 days for egg stage, 60.1－16.4 days for pupal stage between 13－30℃. Larval development lasted for 128.9 days at temperature of 25℃. Adult flight ability was very limited and mainly moved by walking. They became active at night, climbing up trees around sunset and returning to the tree base in the following morning. Adults fed on the inner bark of host branches. Average feeding lasted about 46.3 days before reaching reproductive maturity. Oviposition period was 105.3 days. He eggs were deposited in the outer bark of the stem near the ground. The average fecundity per female was 35.7 eggs. There were five to seven larval instars. Young pine plantations, especially slash pine, were very susceptible to larval attack.