Emerging pervasive computing scenarios require open service frameworks promoting situated adaptive behaviors and supporting diversity in services and long-term evolvability. We argue that this naturally calls for a nature-inspired approach, in which pervasive services are modeled and deployed as autonomous individuals in an ecosystem of other services, data sources, and pervasive devices. As an evolution of standard service-oriented architectures, we present a general framework framing the concepts expressed, and discuss a number of natural metaphors that we can adopt to concretely incarnate the proposed framework and implement pervasive service ecosystems.