Invasion of an Ecological Niche by Lepomis gibbosus in Lakes Without Lepomis macrochirus

单一物种通常被认为是相对统一的实体，占据着单一的“生态位”。然而，最近，生态学家发现，单个物种可能由多个占据不同生态位的专家组成。此外，物种内的生态多样性可能会受到群落中其他物种的严重影响。PIS将在南瓜籽太阳鱼(Lepomis GibBosus)中研究这一重要课题，其地理范围与蓝鳍太阳鱼(Lepomis Manrochirus)部分重叠。在它们共存的地方，蓝鳃是经常以浮游动物为食的生态通才，而南瓜籽是主要以蜗牛为食的生态专家。然而，在没有蓝藻的湖泊中，南瓜种子以两种形态存在，其中一种以浮游动物为食。因此，存在于共生区域的物种之间的生态多样性被存在于异地生长的物种内的相当程度的生态多样性所取代。从基础科学的角度，这项拟议的研究涉及共同进化、适应性辐射、表型可塑性和物种形成等基本问题。这项研究还将具有实际意义，特别是通过表明物种内变异在生物多样性研究中不能被忽视。

Single species are often envisioned as relatively uniform entities that occupy a single "niche." Recently, however, ecologists have discovered that single species can consist of multiple specialists that occupy different niches. Furthermore, ecological diversity within species can be heavily influenced by other species in the community. The PIs will investigate this important subject in pumpkinseed sunfish (Lepomis gibbosus), whose geographical range partially overlaps with the bluegill sunfish (Lepomis machrochirus). Where they coexist, bluegill are ecological generalists that often feed on zooplankton, while pumpkinseed are ecological specialists that feed primarily on snails. In lakes without bluegill, however, pumpkinseeds exist as two morphological forms, one of which feeds on zooplankton. Thus, the ecological diversity that exists between species in areas of sympatry is replaced by a comparable degree of ecological diversity that exists within species in allopatry. From the standpoint of basic science, the proposed research addresses fundamental questions involving coevolution, adaptive radiations, phenotypic plasticity, and speciation. The research will also have practical implications, especially by showing that intraspecific variation cannot be ignored in studies of biodiversity.