Bees. http://en.wikipedia.org/wiki/Varroa_destructor Varroa destructor is an external parasitic mite that attacks the honey bees Apis cerana and Apis mellifera. The disease caused by the mites is called varroosis. Varroa destructor can only reproduce in a honey bee colony. It attaches to the body of the bee and weakens the bee by sucking hemolymph. In this process, RNA viruses such as the deformed wing virus (DWV) spread to bees. A significant mite infestation will lead to the death of a honey bee colony, usually in the late autumn through early spring. The Varroa mite is the parasite with the most pronounced economic impact on the beekeeping industry. It may be a contributing factor to colony collapse disorder, as research shows it is the main factor for collapsed colonies in Ontario, Canada and Hawaii, USA. BUT... Aliens AND global warming.