The Ecological Implications of Energy Acquisition by Social Organisms

EPA Grant Number: U915782
Title: The Ecological Implications of Energy Acquisition by Social Organisms
Investigators: Moses, Melanie E.
Institution: University of New Mexico
EPA Project Officer: Lee, Sonja
Project Period:    
Project Amount: $100,352
RFA: STAR Graduate Fellowships (2000) RFA Text |  Recipients Lists
Research Category: Fellowship - Terrestrial Ecology and Ecosystems , Academic Fellowships , Ecological Indicators/Assessment/Restoration


The objective of this research project is to develop mathematical models and test those models with field observations to understand energetic tradeoffs that occur in social organization.


The mathematical models describe two very different biological systems: modern humans and colonial ants. I show that in modern human populations, fertility declines as energy consumption increases with a scaling exponent of -1/3, in quantitative agreement with allometric models and data from other mammals. The decline may be explained by parental tradeoffs between the number of children and the energetic investment in each child. This analysis of human fertility offers a framework for understanding the demographic transition to smaller family sizes, with implications for human population growth, resource use, and sustainability. The second model and preliminary field observations suggest that ant colonies also face energetic tradeoffs that are analogous to those of other biological systems. The model predicts that energy acquisition rates of ant colonies are a nonlinear function of colony size and available resource density. In Year 3 of the project, I will complete field observations (begun in 2003) and conduct a set of manipulative field experiments to test whether the model accurately predicts seed intake rates in Pogonomyrmex, a genus of granivorous ants that are important consumers in Southwestern deserts and grasslands. The model suggests an important tradeoff across colony sizes: small colonies may maximize energy intake rates by efficiently extracting energy from small territories, while large colonies may maximize energy intake rates by exploiting information about the density of resources in the landscape.

Supplemental Keywords:

fellowship, social organisms, ecological implications, colonial ants, fertility, modern humans, ant colonies, energy intake rates., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Monitoring/Modeling, Environmental Monitoring, Ecology and Ecosystems, Social Science, model-based analysis, environmental measurement, environmental impact, energy consumption, mathematical models

Progress and Final Reports:

  • 2000
  • 2001
  • Final