Conceptual image of a disappearing bee representing Colony Collapse Disorder (CCD), a phenomenon in which bees from a beehive or colony abruptly disappear, noted since 2006. CCD is characterized by the sudden loss of a colony's worker bee population with very few dead bees found near the colony. The queen and brood (young) remain, and the colony has relatively abundant honey and pollen reserves. But a hive cannot sustain itself without worker bees, and it would eventually die. Scientists are still uncertain of the exact cause or causes, but a recent study implicates the widely-used pesticide imidacloprid.