Research into human and animal health covers a vast array of biological components and functions. Yet strategies to simulate entire biological systems across multiple levels, by integrating many components and modelling their interactions, are largely undeveloped. Integration all the way from molecules to behaviour is a huge challenge. We will explore how this challenge can be approached by considering the components and interactions between these requited to build a virtual fly brain. This offers a new proving ground for collaboration between e-Scientists, biologists and neuroinformaticists.