But using the amazingness of pheromones, chemicals that produced by animals to cause changes in the behaviour of others, they have been able to reduce the moth population by half. Male moths are renowned for using their antennae to detect female sexual pheromones to locate potential mates, this is why the males of some species of moth have such large antennae. Males will fly from areas of low concentrations of female sexual pheromones and by detecting changes in the concentration they can slowly move towards the female, and this behaviour is what the Natural History Museum used to such great effect. By using a trap laced with female pheromones they managed to trap males, who then themselves became covered in the same pheromone, attracting yet more males. This species has a short window of reproduction, so trapping the males limited reporduction.
However this is not a perfect solution, as not all of the moths can be caught in such a way in such a large. Now they are turning to the power of parasitism! They are going to use a parasitic wasp, Trichogramma, to bring the numbers of the moth down further. These insects lay their eggs in the larvae of the moth. This form of parasitism is fascinating, with so many factors to investigate: how do females find their host? How do they know if the host already has an egg inside it? How many eggs should they lay in the host? Not to mention the crazy physiology, with some parasites keeping hosts alive while they eat them from the inside! But this form of biological control doesn't always work perfectly, and can lead to introducing a new species with negative effects on the wider environment: such as the cane toad in Australia.
Animals are used widely for controlling other species. For example, Harris hawks are used in London to control the pigeon population. Either using natural predators, tricking animals using their innate behaviours or other methods derived from their biology provide interesting ways of controlling our environment without the use for chemical insecticides, herbicides or fungicides. I remember a study I learned about as an under grad, carried out in China, where they planted different varieties in wheat alternately in fields. This planting method reduced the spread of wheat rust, due to a combination of the different heights that the varieties grew to effecting the transmission and the different varieties having different disease resistance. This sort of stuff is just awesome, showing that the more we learn from the nature the more we can do in the world.