云南元江干热河谷桔小实蝇种群动态及其影响因子分析

Population dynamics of Bactrocera dorsalis (Diptera: Tephritidae) in Yuanjiang dry-hot valley, Yunnan with an analysis of the related factors

分别于1992、1998、2003和2004年在云南元江干热河谷通过性诱剂诱捕,对桔小实蝇雄性成虫数量变化进行了全年监测,并就气候因子及寄主植物对数量变动的影响进行了综合分析.桔小实蝇在元江干热河谷常年发生,当年12月至次年2月,桔小实蝇种群较低,3月以后逐渐上升,于6～8月形成增长高峰,9～11月种群迅速下降.近两年桔小实蝇种群数量较上世纪90年代明显增大.月均温、月均降雨量和寄主植物是影响元江桔小实蝇种群变动的主要因子.元江干热河谷各月均温在桔小实蝇适温区内,为其常年发生提供了温度条件.但12～2月的月平均最低温度低于桔小实蝇的适温下限,而5月的月平均最高温超过桔小实蝇的适温上限,这两方面对桔小实蝇种群均有一定抑制作用.元江夏季6至8月的月降雨量为100～150 mm,有助于桔小实蝇种群增长.芒果和甜橙是元江桔小实蝇最喜好的寄主水果,其种面积、挂果期是影响桔小实蝇种群变动的重要因素.气温、降雨和寄主植物通过各自的作用方式和发生时间综合影响着元江干热河谷地区桔小实蝇种群变动.

The population dynamics of the oriental fruit fly, Bactrocera dorsalis （Hendel） （Diptera： Tephritidae） was monitored through methyl eugenol-baited traps all year around in 1992, 1998, 2003 and 2004 in Yuanjiang dry-hot valley area, Yunnan, and meanwhile, the factors including temperatures, rainfall and host-plant species were analyzed systematically in relation to the population fluctuation of the fly. The results indicated that the fruit fly occurred all year round in Yuanjiang. Its population size remained low from December to February of next year and increased steadily from March through August till it reached the peak. Afterwards, the fruit fly population declined until November. Temperatures, rainfall and host fruits were supposed to be the major factors influencing the population fluctuation. The monthly mean temperatures fell into the ranges of temperatures suitable for development and reproduction of the fly in the study area. But, the monthly mean minimum temperatures from December to February of next year appeared to be lower, and were suggested to be responsible for the low populations in this period. In contrast, the monthly mean maximum temperatures in May were too high and may have negative effect on the fly populations. Rainfall was another essential factor influencing the population fluctuations. Rainfall in summer months from June through August ranged between 100-150 mm, being helpful for the fly population increasing. Mango and orange were the most preferred host-plants for the fly. The planted areas, fruiting period and productions of the two fruit plants exerted essential effects on the fly population fluctuations in Yuanjiang valley area. Briefly, the monthly mean temperature, monthly rainfall and the host plant species, through the way of their functions, their influence strength, as well as the period that they occurred, synthetically impacted the population dynamics of the fruit fly in the study area.