Organisms exhibit a vast number of properties (organs and patterns of behaviour) that assist in their successful survival and reproduction. Some organs assisting in successful survival are quite simple and their usefulness and means of evolution are easy to discover (fins for swimming, parachutes on dandelion seeds for dispersion), while others are highly ingenious. For example, some kinds of orchids (Ophrys) have a structure in their flowers whose shape, colour and scent are similar to the females of a certain kind of fly. Thus, males are attracted to the flowers and attempt to copulate with the dummy female and thus transfer pollen from one flower to the next. Tobacco and cotton plants can recognize that they are being eaten by the caterpillars of the moth Heliothis virescens (tobacco budworm) (they can even distinguish that they are being damaged by this pest and not the caterpillars of some other kind of moth or a scientist punching holes in the leaves). In order to get rid of the intruder (or at least to make his life harder), they begin to emit chemical substances that attract the natural enemies of this kind of caterpillar, the parasitoid wasp Cardiochiles nigriceps, which lays eggs in the caterpillar. These parasitoid wasps fly to the plants even if the scientist first removes the caterpillars and the damaged leaf. The plants do, of course, not know that they are doing this – in this sense, it is not truly goal-oriented behaviour. However, it is certainly useful behaviour as it truly effectively assists the plant to get rid of the particular species of pest.