In mobile ad hoc network, the cooperation between the nodes is essential to discover and maintain routes. The node cooperation is not always guaranteed because of the misbehaving nodes which exist due to its constraint resources such as battery, bandwidth and computational power. When the node colludes to misbehave, it further makes the routing process difficult due to frequent network partitioning and it results in degrading the overall network throughput. This paper addresses three different kinds of packet dropping misbehavior and proposes a collaborative polling scheme to detect and isolate the colluding packet droppers. The simulation result shows that packet drop ratio, malicious packet drop and false detection has been greatly reduced when compared to the existing system under both entity and group mobility scenario.