DISSERTATION RESEARCH: Elucidating the Roles of Abiotic and Biotic Factors in Exotic Species Establishment: A Trait-based Approach

对非本土物种的入侵是21世纪最大的环境挑战之一，不仅威胁到本土动植物及其提供的生态系统服务，而且威胁到农业、人类健康和经济。非本地物种的入侵和建立既有物理(非生物)因素，如温度，也有与本地物种的相互作用(生物因素)，如捕食和竞争。了解这些生物和非生物因素如何相互放大或抵消，对于预测入侵物种在新地点生存的条件，以及开发控制此类物种传播的方法是必要的。然而，大多数研究忽略了非生物和生物因素对入侵成功的联合影响，因为他们只研究了一种类型的因素。这个项目通过研究环境温度和对资源的竞争对加州昆虫入侵的联合影响来解决这个问题。这项研究结合了实验室实验、实地观察和数学模型来预测允许入侵物种传播的条件。目前，美国每年在入侵物种控制上花费数亿美元。该项目旨在通过提供开发更具成本效益的控制措施所需的科学知识来降低这一成本。该项目整合了操纵实验、田间观察和数学模型，以研究温度和竞争如何影响一对生态相关的昆虫的种群动态和物种相互作用，一对本地昆虫和一对入侵昆虫。这项工作的动力来自于加州沿海鼠尾草灌丛群落中发生的原生和入侵的相互作用，在该群落中，两种半翅目动物(科：五角蜂科)、本地的Histrionica和最近的北美入侵的bagrada Hilaris争夺它们的主要宿主-多年生灌木Cleome isomis。这项研究的目的是(I)量化温度和密度对两个物种生活史特征(繁殖力、发育、死亡率)的联合影响，以及(Ii)将阶段结构种群动态的数学模型参数化，该模型结合了对生命速率、温度响应和由于温度变化而产生的依赖于时间的发育延迟的机械描述。这些目标是通过(I)密度和温度处理的全因子实验室实验，(Ii)使用实验数据的最大似然方法估计模型参数，用于分析种群动态的延迟微分方程模型，以及(Iii)现场收集昆虫丰度来验证模型的预测，来实现这些目标。

Invasions of non-native species are one of the greatest environmental challenges of the 21st century, threatening not only native flora, fauna, and the ecosystem services that they provide, but also agriculture, human health, and the economy. Invasion and establishment of non-native species is driven by both physical (abiotic) factors, such as temperature, and by interactions with native species (biotic factors), such as predation and competition. Understanding how these biotic and abiotic factors magnify or cancel one another is necessary for forecasting the conditions under which invasive species establish in new localities, and for developing methods to control the spread of such species. Yet, most studies overlook the joint effects of abiotic and biotic factors on invasion success because they examine on only one type of factor. This project addresses this problem by examining the joint effect of environmental temperature and competition for resources on invasion by an insect in California. The research combines laboratory experiments, field observations, and mathematical models to forecast the conditions that allow the invasive species to spread. Currently, the U.S. spends hundreds of millions of dollars annually on invasive species control. This project aims to reduce this cost by providing the scientific knowledge needed to develop more cost-effective control measures.The project integrates manipulative experiments, field observations and mathematical models to examine how temperature and competition impact population dynamics and species interactions of an ecologically related pair of insects, one native and one invasive. The impetus for this work comes from a native-invasive interaction occurring in the California coastal sage scrub community in which two Hemipterans (Family: Pentatomidae), native Murgantia histrionica and recent North American invasive Bagrada hilaris, compete for their primary host, the perennial shrub Cleome isomeris. This study aims to (i) quantify the joint effect of temperature and density on life history traits (fecundity, development, mortality) of the two species, and (ii) parameterize a mathematical model of stage-structured population dynamics that incorporates mechanistic descriptions of vital rate temperature responses, and time-dependent developmental delays that arise due to temperature variation. These goals are achieved through (i) a fully factorial lab experiment with density and temperature treatments, (ii) estimation of model parameters using maximum likelihood methods applied to experimental data, which are used to analyze a delay differential equation model of population dynamics, and (iii) field collection of insect abundances to test the model's predictions.