Spatial Scaling with an Unusual Food Web Structure: The Case of Azteca Ants in the Coffee Agroecosytem

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Nature is not arranged in a uniform way. Patches are evident wherever you look, from localized disease outbreaks, to species of plants in the forest, to barnacles on the tidal rocks. This spatial aggregation of species and ecosystems has intrigued ecologists for many years and many techniques exist for describing the existing patterns. However, it is frequently quite enigmatic how the patterns are formed, what it is that creates the patches in the first place. In this research a common species of ant that occurs throughout the new world tropics, and is regarded as a potential pest species in several crops, is known to occur in relatively large patches. It is also known to protect scale insects from ever-present parasitic wasps, but is frequently attacked by a species of parasitic fly. The local dynamics thus involve two "predator-prey" systems (wasp versus scale insect and parasitic fly versus ant) coupled together with a key mutualism (the ant's protecting the scale insects). Using recent advances in ecological theory, these local details will be translated into a mathematical model that will then be used to explore the underlying mechanisms of how the patches are formed, and what their ultimate fate might be.