As interest in wireless mesh networks grows, security challenges, e.g., intrusion detection, become of paramount importance. Traditional solutions for intrusion detection assign full IDS responsibilities to a few selected nodes. Recent results, however, have shown that a mesh router cannot reliably perform full IDS functions because of limited resources (i.e., processing and memory). Cooperative IDS solutions, targeting resource constrained wireless networks impose high communication overhead and detection latency. To address these challenges, we propose a non-cooperative real-time intrusion detection scheme that optimally distributes IDS functions to nodes along traffic paths, such that intrusion detection rate is maximized, while resource consumption is below a given threshold. We formulate the optimal IDS function distribution as an integer linear program and propose algorithms for solving it accurately and fast (i.e., practical). We evaluate the performance of our proposed solution in a real-world, department-wide, mesh network.