As long as the blocks remain red -- they revert to green once you shoot an insect -- it is possible to disintegrate them with your weapon. But the best measure to prevent being boxed-in is by blasting away whenever they're carrying their blocks in their enormous mandibles. This will do away with both the block and the termite simultaneously. If, however, you can't spray the little bugger before it drops its block, you can still earn points for shooting the termite as it escapes.
Meanwhile, to make things even more complicated, you have to refuel every time you hear the warning signal by docking with one of the ships cruising along the side of the screen. If you can't make it, you lose the game immediately.
Graphically, Cosmic Swarm is quite unappealing unless you're into Arabic literature (look closely, the bugs look like Arabic symbols!). But it does provide an action-filled, challenging scenario with plenty to keep you occupied.