Monster From Green Hell (1957)

The U.S. government is conducting experiements on the effects of exposure to space radiation by sending animals briefly into orbit. Following a malfunction, one of the rockets stays in space longer than planned, and is lost from the scientists' radar screens. Later, Dr. Brady, one of the rocket scientists, reads a news report about strange occurances in Central Africa. Theorizing that it may be the irradiated test wasp wreaking havoc in the jungle, he organizes an expedistion to investigate.