Behavior is shaped by genes, environment, and evolutionary history in different ways. Nest architecture is an extended phenotype that results from the interaction between the behavior of animals and their environment. Nests built by ants are extended phenotypes that differ in structure among species and among colonies within a species, but the source of these differences remains an open question. To investigate the impact of colony identity (genetics), evolutionary history (species), and the environment on nest architecture, we compared how two species of harvester ants, Pogonomyrmex californicus and Veromessor andrei, construct their nests under different environmental conditions. For each species, we allowed workers from four colonies to excavate nests in environments that differed in temperature and humidity for seven days. We then created casts of each nest to compare nest structures among colonies, between species, and across environmental conditions. We found differences in nest structure among colonies of the same species and between species. Interestingly, however, environmental conditions did not have a strong influence on nest structure in either species. Our results suggest that extended phenotypes are shaped more strongly by internal factors, such as genes and evolutionary history, and are less plastic in response to the abiotic environment, like many physical and physiological phenotypes.

中文翻译：

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收割机蚁巢结构受内在因素的影响比外在因素更强烈。

行为是由基因、环境和进化历史以不同方式塑造的。巢结构是一种扩展的表型，是动物行为与其环境相互作用的结果。蚂蚁建造的巢穴是扩展的表型，在不同物种之间和同一个物种内的蚁群之间结构不同，但这些差异的来源仍然是一个悬而未决的问题。为了研究蚁群特性（遗传学）、进化史（物种）和环境对巢穴结构的影响，我们比较了两种采伐蚁（Pogonomyrmex californicus 和 Veromessor andrei）如何在不同环境条件下构建它们的巢穴。对于每个物种，我们允许来自四个殖民地的工人在温度和湿度不同的环境中挖掘巢穴 7 天。然后，我们创建了每个巢穴的模型，以比较不同群体、不同物种和不同环境条件下的巢穴结构。我们发现同一物种的群体之间和物种之间的巢结构存在差异。然而，有趣的是，环境条件对这两个物种的巢穴结构都没有产生强烈影响。我们的研究结果表明，扩展表型受内部因素（如基因和进化历史）的影响更大，并且对非生物环境的反应更不易塑，就像许多物理和生理表型一样。环境条件对任一物种的巢结构都没有强烈影响。我们的研究结果表明，扩展表型受内部因素（如基因和进化历史）的影响更大，并且对非生物环境的反应更不易塑，就像许多物理和生理表型一样。环境条件对任一物种的巢结构都没有强烈影响。我们的研究结果表明，扩展表型受内部因素（如基因和进化历史）的影响更大，并且对非生物环境的反应更不易塑，就像许多物理和生理表型一样。