War of the Roses

No visitor to the hills would have been spared the attentions of the bichchu booti,that notorious stinging nettle whose hair-like hypodermic barbs cause horrible inflammation. They say a plant belonging to the spinach family usually grows next to it and is an antidote,but Ive never checked.

Have you watched a bug get caught in pine resin? Its the sticky ending to end all sticky endings and the beginnings of a fossil a million years down the line. The latex of rubber plants turns sticky on contact with air and gums up the mouth parts of insects: the ultimate anti-chewing-gum weapon if you like. Singapore might be interested. The infamous milkweed family of plants the aak or Calotropis,for example produces milk so poisonous it can give cows a heart attack. Some plants give off hydrogen cyanide when bitten the rest,as they say,is history. Others release bitter tannins which jam up digestion which is why tea kills the appetite and provide little nutrition.

But some plants are even more diabolical theyre into biological warfare which can turn their enemies into time-warp freaks. Some contain large amounts of the juvenile larval hormones of predator insects,which cause these to remain frozen in the larval stage and die without reproducing. Others contain hormones which fast-forward the development of the insect skipping out important larval stages and causing them to become adults too quickly almost like what were doing to our children,only in different ways. Weve made horror films using these themes but it really is the stuff of nightmares. Imagine using hormone therapy that can turn warmongers and terrorists into drooling,dribbling idiots mumbling la-la-ga-ga-ba-ba-da-da! for the rest of their short,pathetic lives. And alas,there are already so many people you would love to use this for!

There are other strategies for defence. Some plants,like the tobacco,can sense a viral attack and warn each other about it: they release a gas no,not cigarette smoke that is absorbed by neighbouring plants and helps in improving the plants defence against the virus. Tender young leaves are laden with toxins and dont turn green and appetising till fully grown.

Like any arms race,it is an expensive business. The energy costs to the plant

and similarly to countries engaged in the same are enormous and may stunt its growth as in rubber plants that are tapped for their latex.

But,of course,the predators have struck back. Caterpillars of the milkweed family of butterflies are not only immune to the sap of its milkweed food plant,but store the toxins for their own use against predation by birds. Others simply bite the midrib of the leaf and let the poison drip away. The tough leathery tongues of giraffes make short work of even the most ferocious crown of thorns.

For us,this arms race is good news isnt it always?. The defensive chemicals that plants use form the active ingredients of practically all medicines that come from plants,which comprise 40 per cent of all prescription drugs. There is no end in sight to these countless Wars of the Roses being fought all over the world.

And we havent even touched upon those plants which have turned the tables and gone carnivorous. Thats another story vegetarians would love. n

Ranjit Lal is an author,environmentalist and bird watcher. In this column,he reflects on the eccentricities and absurdities of nature