Carbon nanomaterials hold great promise for applications ranging from electronics to medicine. But their environmental impact is still being determined, with most toxicological studies conducted so far on cultured cells rather than on intact organisms. That’s why Xinyuan Liu, Robert H. Hurt, David M. Rand, and coworkers of Brown University studied the effects of carbon nanomaterial exposure on fruit fly larvae and adults (Environ. Sci. Technol., DOI: 10.1021/es901079z). The researchers found that when larvae ingested various types of carbon nanomaterials, there was, surprisingly, no impact on development or survival, although some nanomaterials accumulated in tissues. In contrast, exposing adult flies to dry powders of some carbon nanomaterials impaired their mobility and caused them to die within hours. Nanomaterials that form small aggregates, such as carbon black and single-walled nanotubes, were more toxic to the flies than nanomaterials with larger aggregate sizes, they noted, probably because the small aggregates strongly adhere to the flies’ eyes, legs, wings, and breathing holes. In a test-tube assay, flies were observed spreading attached nanomaterials to uncontaminated flies while grooming themselves, which suggests that insects could transport carbon nanomaterials from manufacturing or waste sites.