Insects and plants. Feromony and any chemical signals

you are: Insects and plants

The Great number of similar connections at plants and insects testifies that many insects borrow plants skeletons of some molecules which they are not capable to synthesise. They, in particular, receive from plants skeletons izoprenoidnyh connections and, in appropriate way them modifying, build of them molecules of the hormones and various protective substances. We find a curious example in mutual relations duglasii (Pseudotsuga taxifolia) and duglasievogo luboeda (Dendroctonus pseudotsugae). Duglasija allocate at damage flying terpeny, involving the first female luboeda which then allocates attraktant, involving from apart other females and males. And though all it does not prevent luboedam to be fed on duglasii, the person could use this phenomenon as the most reliable tool of struggle against insects-wreckers. Females of many insects allocate sexual attraktanty (fig. 15.6 see), concerning to feromonam; Such attraktanta it is enough several molecules that, to involve the males who are for many kilometres from this place. By this time it was possible to identify, and then and to synthesise in vitro over such 50 feromonov. These connections can be used to entice all males from any extensive area in a trap and to destroy them. it is possible to arrive and in another way: having sprayed all around, to disorient males so, that they could not find females and by that to prevent reproduction of population of insects.

Among chemical signals of insects is available and a warning signal. The disturbed plant louse, for example, allocates special substance - an alarm signal under which influence other plant louses being nearby fall to the ground. The similar substance or any its simple analogues can be used as constantly operating repellent. for this purpose it is enough absolutely small amounts feromona so sometimes at all it is not required to resort to spraying; and as available for insects feromony vidospetsifichny, substance action is limited in this case to one only a kind-target. Predators of insects-wreckers thus do not suffer and, hence, can finish with the escaped individuals. The given biological method also can serve for struggle against insects-wreckers, and though while it is recognised by effective enough only on occasion, in the future it, possibly, wide application will find. One of the most essential features insektitsidov selective action consists that with their help the natural biological control can be carried out continuously. (detailed discussion of the dangers connected with application hlororganicheskih of pesticides, and data on other possible methods of protection of plants the reader will find in Rachel Carson's fine book ' Silent spring ' (Rachael Carson ' Silent Spring ') and in its continuation written by Frenkom Graham, ' After silent spring ' (Frank Graham ' Since Silent Spring '.)