Recent years have witnessed a surge in self-organizing voluntary teams collaborating online to produce goods and services. Motivated by this phenomenon, this research investigates how these teams are formed and how individuals make decisions about which teams to join in the context of open source software development (OSSD). The focus of this paper is to explore how the collaborative network affects developers' choice of newly initiated OSS projects to participate in. More specifically, by analyzing software project data from real-world OSSD projects, we empirically test the impact of past collaborative ties with and perceived status of project members in the network on the self-assembly of OSSD teams. Overall, we find that a developer is more likely to join a project when he has strong collaborative ties with its initiator. We also find that perceived status of the noninitiator members of a project influences its probability of attracting developers. We discuss the implications of our results with respect to self-organizing teams and OSSD.