Scanning electron micrograph of the head of a mealworm. Mealworms are the larval stage of the darkling beetle (Tenebrio molitor) and are found all over the world in dark, damp places such as under decaying organic matter. They eat plant material and animal products such as grains, vegetation, rotten food and other fresh and decaying organic matter and are themselves a source of food for many birds, fish and reptiles. Width of image is 3.6 mm. Supplied by Kevin Mackenzie, courtesy of Wellcome Images.