棉花生境面积及其破碎化对棉蚜数量的影响

为探讨农作物面积减少及其破碎化对害虫种群的影响,采用微景观试验模型系统连续2年研究5个梯度棉花生境面积(棉花种植比例分别为20%、40%、60%、80%和100%,其余均种植玉米)及2种破碎化(完全连通与完全破碎)对棉蚜Aphis gossypii数量的影响。结果表明,棉花生境面积较小(棉花种植比例为20%)时破碎化程度越高,棉蚜数量越多,而生境面积较大(棉花种植比例为40%)时棉蚜的响应正好相反;生境面积中等(棉花种植比例为60%)时,破碎化程度对棉蚜数量影响不大;生境面积大(棉花种植比例为80%)时,破碎化对棉蚜数量的影响存在年度效应,2014年破碎化程度越大,棉蚜数量越少,2015年则无影响。棉花生境面积、破碎化及两者之间的互作对棉蚜数量无显著影响,棉花生境面积、破碎化与调查时间的互作也不影响棉蚜数量,但调查时间显著影响棉蚜数量,棉花生境面积、破碎化与调查时间三者之间的互作效应呈年度变化。总之,棉蚜对棉花面积变动及其破碎化展示出较强的适应性。

Effects of cotton planting area and fragmentation on the abundance of cotton aphid Aphis gossypii

To elucidate the effects of crop habitat area and fragmentation on insect pests, the experimental model landscape system was used to study five levels of cotton habitat areas (the planting ratios of cotton were 20%, 40%, 60%, 80% and 100%, respectively) and two kinds of fragmentation (fully clumped and totally fragmented) on the abundance of the cotton aphid Aphis gossypii. The results showed that, when cotton habitat area was small (the planting ratio of cotton was 20%), the higher the fragmentation, the more the aphids; when cotton habitat area increased (the planting ratio of cotton was 40%), the higher the fragmentation, the less the aphids; when cotton habitat area was medium (the planting ratio of cotton was 60%), cotton aphids were not affected by fragmentation; when cotton habitat area was larger (the planting ratio of cotton was 80%), fragmentation had an annual effect on the number of aphids and aphids reduced in fragmented habitats in 2014, but no difference was observed between fragmentations in 2015. Cotton habitat area, fragmentation and their interactions did not significantly impact the number of cotton aphids, and the aphids were also not affected by the interaction between cotton habitat area and survey time, and between the fragmentation and survey time. However, the survey time showed a significant influence, and the interactions among cotton habitat area, fragmentation and survey time depended on the years surveyed. In conclusion, A. gossypii showed a strong suitability for the change in cotton habitat area and fragmentation.