Can optimal energy allocation in bioenergetic models improve predictions?

所有生物都通过食物消耗能量，并将这些能量用于日常活动，包括生长、繁殖和身体维持。科学家通常使用能量收支模型来描述和预测这种能量在个体生物中的流动。现有的模型对不同过程的能量分配使用了不切实际的假设，因此，它们经常做出不准确的预测。本研究将修改这一标准建模方法，纳入最优能量分配，假设生物体进化到以最大化其未来生存和繁殖的方式分配能量资源。使用这种新建模方法的预测将与标准建模方法的预测进行比较，两者都将用于预测动物在受伤后应该如何分配能量。亚洲岸蟹是一种入侵美国东海岸从北卡罗来纳州到缅因州的岩石海岸的物种，它将被用作模型生物来检验这种新的最佳建模方法比标准方法提供更好的预测。能量分配将通过对失去一条或多条四肢的螃蟹进行实地和实验室研究来检验。该研究还将为来自代表性不足背景的初中生和高中生提供早期科学培训，方法是让参加现有暑期项目的学生使用这些模型进行预测，然后使用实地收集的数据对这些预测进行测试。现有的生物能量模型通常假设固定的能量分配策略，因此产生的预测往往不准确。本研究采用四步优化能量分配的方法，改进生物能量模型，重点研究入侵亚洲滨蟹（Hemigrapsus sanguineus）非致死损伤后的能量分配。第一步是建立包括损伤在内的生物能量学模型。第二步是测量条件相关的代谢率，以完成生物能量学模型的参数化。第三步采用动态变量建模框架下的生物能量模型，确定损伤蟹的最佳能量分配策略与蟹龄、身体状况、损伤状态、繁殖状态以及相对于繁殖季节的时间有关。第四步是对模型预测进行实证检验，以确定包含最优能量分配策略的模型是否比具有固定能量分配策略的零模型表现更好。这项工作将提高我们对非致命性损伤的能量反应的理解，将为理解何时应该优先考虑损伤恢复提供一个一般的理论框架，并将展示一种建模策略，可以预测和澄清能量分配中与环境相关的权衡。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

All organisms consume energy via food and use that energy for daily processes, including growth, reproduction, and body maintenance. Scientists commonly use energy budget models to describe and predict the flow of this energy through individual organisms. Existing model use unrealistic assumptions about the partitioning of energy to different processes, and as a result, they often make inaccurate predictions. This research will modify this standard modeling approach to incorporate optimal energy partitioning, assuming that organisms evolve to partition energy resources in a way that maximizes their future survival and reproduction. Predictions using this new way of modeling will then be compared to predictions from the standard modeling approach, and both will be used to predict how animals should allocate energy after an injury. The Asian shore crab, a species that has invaded rocky shores along the US east coast from North Carolina to Maine, will be used as a model organism to test the hypothesis that this new optimal modeling approach provides better predictions than the standard approach. Energy partitioning will be examined through field and laboratory studies in crabs that have lost one or more limbs. The research will also provide early scientific training to junior high and high school students from underrepresented backgrounds by involving students from an existing summer program in making predictions using the models, and then testing these predictions using data collected in the field.Existing bioenergetic models generally assume fixed energy allocation strategies, and consequently yield predictions that are often inaccurate. This research uses optimal energy allocation in a 4-step process to improve bioenergetic modeling, with a focus on studying energy allocation following nonlethal injury in the invasive Asian shore crab Hemigrapsus sanguineus. The first step is to develop a bioenergetics model that includes injury. The second step is to measure condition-dependent metabolic rates needed to complete the parameterization of the bioenergetics model. The third step uses the bioenergetic model within dynamic state variable modeling framework to identify the optimal energy allocation strategy of injured crabs as a function of crab age, body condition, injury status, reproductive status, and time of the year relative to the reproductive season. The fourth step is empirically testing model predictions to determine whether a model that includes an optimal energy allocation strategy performs better than a null model with a fixed energy allocation strategy. The proposed work will improve our understanding of the energetic responses to nonlethal injury, will provide a general theoretical framework for understanding when injury recovery should be prioritized, and will demonstrate a modeling strategy that can predict and clarify context-dependent tradeoffs in energy allocation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.