Harrison Susan
Division of Environmental Studies, U. C. Davis, 95616, Davis, CA, USA.
Oecologia. 1995 Aug;103(3):343-348. doi: 10.1007/BF00328623.
Both induced and maternal effects may create delayed negative feedback on the population growth of herbivorous insects. I tested for these effects in a chronically dense population of tussock moths (Orgyia vetusta) feeding on bush lupines (Lupinus arboreus). Experimental bushes received different realistic levels of defoliation by tussock moths in the preceding year, and experimental moth larvae came from mothers that had experienced either high or low levels of crowding as larvae in the previous year. Weight of female moths at pupation was not affected by prior foliar damage, and showed only a weak (12%) effect of maternal crowding. Rates of early larval disappearance, from aerial dispersal ("ballooning") or other causes, were unaffected by either foliar damage or maternal crowding, and were very low except when larvae were placed on dead bushes. These results help to explain why the tussock moth population has maintained high densities at the study site for >10 years.
诱导效应和母体效应都可能对食草昆虫的种群增长产生延迟的负反馈。我在一个长期密集的以灌木羽扇豆（Lupinus arboreus）为食的毒蛾（Orgyia vetusta）种群中测试了这些效应。实验灌木在前一年遭受了毒蛾不同程度的现实性落叶，实验蛾幼虫来自前一年幼虫期经历过高密度或低密度拥挤的母体。化蛹时雌蛾的体重不受先前叶片损伤的影响，仅显示出母体拥挤的微弱（12%）效应。早期幼虫因空中扩散（“气球状飘浮”）或其他原因消失的速率，既不受叶片损伤的影响，也不受母体拥挤的影响，而且除了将幼虫放置在枯死灌木上时，该速率非常低。这些结果有助于解释为什么在研究地点毒蛾种群已经保持高密度超过10年。
