Fascinating, indeed!!!
Those plants that can detect the difference between the eggs of different insects, and the ones that can "feel" who's walking on their surface is truly amazing!!!!
I remember PBS special documentary about plant communications.
One of which was this species of acacia ( forgot the whole name) in Africa. Animals (deer looking of sort like impala, though they were not impala) were found dead all over the field.
The park team started investigated the cause.
It took them a while to eventually figure out that the cause of their death was toxin produced by this acacia the animals were feeding on.
What happened was this acacia is always eaten by these animals without any harm, but one particular year, the population of the animals increased, thus more of them were eating these trees.
The trees that noticed that they are being eaten more than they should be, started making this chemicals and released in the air, which was picked up by other trees of this same species and these trees made toxins to lethal level to these animals.
When they came to feed on these trees, the ones that ate the leaves all died.
Quote:
Originally Posted by camille1585
Increasing levels of the toxic compounds does harm them to some extent, but it's just going to slow their growth (so smaller caterpillars) somewhat rather than kill them. It's an evolutionary arms race of sorts. Some plant species don't even bother to ramp up toxin production when attacked by specialists. It's a waste of energy to produce it since it will have limited effect. So the plant's strategy is to relocate its carbon stores in the roots to preserve it's growth potential, and then primarily fight the specialist by attracting natural enemies of the specialist, or wait for the insect to leave and then regrow.
Other plants, like black mustard (which I study) goes into growth overdrive when they detect specialist caterpillars (They can detect the eggs on the leaves just minutes after the butterfly lays them, and react differently if the eggs are from a specialist or a generalist) and accelerates its seed production to grow faster than the caterpillars can eat. Heck some plants ramp up defenses just when they feel an aphid walking across a leaf (because yes, they can sense that too), to get ready for an attack. Plants even "talk" to each other via airborne signals to warn of attacking insects/disease, and the unaffected plants get ready by increasing the defenses.
The toxic compounds don't cause all the generalist insects to drop dead immediately either. Some may nibble on the plant and eventually be deterred by the taste and then leave, others will continue feeding but their growth is so badly affected that they never make it to the adult stage. The plants goal isn't to be completely damage free, but to limit damage enough that their reproduction isn't affected.
I find this field of study absolutely fascinating. If vegetarians even knew a tenth of it, they would reconsider eating plants as well!
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---------- Post added at 03:33 PM ---------- Previous post was at 03:27 PM ----------
Then, there are herbs that are still attacked by bugs.
I find that pretty much all common herbs that we love to use in cooking are eaten by spider mites.
At least, lemon verbena, I LOVE the smell of their leaves!
they are like spider mites magnets.
I have seen certain mints, not the common mint with rather large leaves, which I find rather pest free, get easily attacked by thrips.
Let's see...rosemary is quite resistant but underwatering in pots bring them spider mites also.
Lemon Balm was also easily eaten up by thrips and mites, but I think that was also either not enough light in the garden or underwatering.
I'm sure when grown very healthy, they will fend off these bugs quite easily.
Oh, and then dill, I don't think dill is ever attacked by any common pest, except the beautiful swallowtail butterfly like to lay eggs on them, but I love them also!
I'd rather see some bugs that will eat the entire part then something that make holes or ugly spots or things like that. lol
Quote:
Originally Posted by Leafmite
I wish all of my plants had it!
Some of the 'medicinal' herbs do not seem to have any problems protecting themselves: wormwood, rue, tansy, Valerian, and soapwort, for example. Then there are the other plants I grow (roses, fruit trees), attacked by everything under the sun. Of course, some pests are really welcome...I love seeing the parsley bare of all leaves as it means I will be seeing swallowtail butterflies (the parsley always gets new leaves).
Pretty interesting work you are doing there, camille1585. Plants are really fascinating. |
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