The policy also deters or prevents venture capitalism. It also deters potential violators and, thus, further protects the environment. Large white butterflies emit an unpleasant smell which deters predators. The insect produces carminic acid that deters predation by other insects. The insect produces carminic acid, which deters predation by other insects. Research suggests immigration enforcement deters unauthorized immigration but has no impact on crime rates. Propolis also contains persistent lipophilic acaricides, a natural pesticide that deters mite infestations. Other species such as the rainbow grasshopper have warning coloration which deters predators. While taking off they produce a sudden thundering noise that deters predators. This scent mark deters bumblebees from visiting that flower until the scent degrades. Aversive conditioning deters bears by modifying their behaviour. The oil impregnation also deters insect damage. The female flowers eventually form a spiky sheath that deters predators from the seed. Finally, vile-tasting mucus deters predation. This, along with the raising of the sharp quills, deters predators.