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Demographic consequences of inflorescence

花匠小妙招
2025-01-27 05:01

摘要

While floral herbivores and predispersal seed predators often reduce plant reproductive output, their role in limiting plant fitness and population growth is less clear, especially for iteroparous perennial plant species. In this study we experimentally excluded floral herbivores and predispersal seed predators (insecticide spray versus water control) over a 2-year period to examine the effect of inflorescence-feeding insects on levels of seed production, seedling emergence, and juvenile establishment for Liatris cylindracea, an iteroparous perennial plant. In addition, we collected detailed demographic data on all life stage transitions for an additional set of individuals in the same population over 4 years. We used the experimental and demographic data to construct stochastic individual-based simulations to evaluate the overall effect of inflorescence-feeding insects on adult recruitment per maternal plant (a fitness component) and population growth rate. The insect exclusion experiments showed that damage due to insects decreased seed production, seedling emergence, and juvenile establishment for both years' experiments. These results indicate that recruitment was seed-limited through juvenile establishment, and that inflorescence-feeding insects influenced the degree of seed limitation. Results of the individual-based simulation models, which included individual demographic and temporal stochasticity, showed that inflorescence-feeding insects negatively affected the number of adult offspring per maternal plant recruited into the population and population growth rate for both years' experiments. Taken together, the results of the experimental exclusions and the individual-based models indicate that inflorescence-feeding insects can influence population growth rate, and have the potential to act as a selective force for the evolution of traits in this plant species.展开▼

机译：尽管花卉食草动物和种子前捕食者经常减少植物的繁殖产量，但它们在限制植物适应性和种群增长方面的作用尚不清楚，特别是对于多年生异形植物。在这项研究中，我们在2年的时间里实验性地排除了草食性动物和种子前掠食者（杀虫剂喷雾与水控制），以研究以花序摄食的昆虫对Li草的种子产量，幼苗出苗和幼年建立的影响，多年生的异种植物。此外，我们还收集了有关4年内同一人口中另一组个体所有生命阶段过渡的详细人口统计数据。我们使用实验数据和人口统计学数据构建了基于个体的随机模拟，以评估以花序摄食的昆虫对每株母本植物（适应性成分）的成年募集和种群增长率的总体影响。昆虫排斥实验表明，两年来由于昆虫引起的损害降低了种子产量，幼苗出苗和幼体定殖。这些结果表明，通过幼年建立，募集受到种子限制，而以花序摄食的昆虫影响种子限制的程度。基于个体的模拟模型的结果（包括个体的人口统计和时间的随机性）表明，在两年的试验中，以花序喂养的昆虫对招募到种群中的每个母本植物的成年后代数量和种群增长率均产生了负面影响。两者合计，实验排除和基于个体的模型的结果表明，以花序摄食的昆虫可以影响种群的生长速度，并有可能作为该植物物种性状进化的选择性力量。展开▼