Key pre-distribution in nodes is often employed to address the problems of security with a single secret key and management with pair-wise secret keys in ad hoc and sensor networks. Sensor nodes can establish secure links with their neighbors through shared key predistributed before node deployment. At the ends of the spectrum of key pre-distribution schemes are random and deployment based key pre-distribution. Random key pre-distribution suffers from a smaller probability of sharing keys with neighbors. Deployment based key pre-distribution has a near 100% probability of sharing keys with immediate neighbors but not with nodes that are further away. When a network is jammed and jamming coping techniques (such as increase in power, use of directional antennas, and spatial retreats) are used, the nodes that are new neighbors due to changes in physical connectivity may or may not share keys with a given node. In this paper, we examine the impact of increasing transmission power to cope with jamming on secure connectivity (provided by different key predistribution schemes) in ad hoc and sensor networks.