James Stewart
speaker
4,486 appearances
22 recordings
2 series
first heard Apr 2025
last heard 5d ago
James Stewart’s voice in public audio — every appearance, attributed to the second.
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recordings per month · last 12 monthsRecordings per month over the last 12 months — 17 in all, peaking in Sep 2026 with 3.
Appearances
Astrum Space · The Science Fact You've Been Taught for Years Is a Lie | Astrum Earth · 28 Apr 2026
podcast
These studies were suggesting that when a tree is attacked by a herbivore and damaged in some way, its neighbours could pick up on this and prepare themselves for an attack.
This is possible, as trees have a host of chemicals they can use in herbivore defence, like bitter tasting tannins or toxic alkaloids, which have been shown to be effective tools in fending off pests.
And scientists could be pretty sure that it was VOCs that were inducing these responses, since any efforts to block airborne signals by putting the tree branches in airtight bags meant that neighbouring trees took more damage from the herbivores.
But hang on, because there's a danger here of entering into the same minefield as the wood wide web drama.
This behaviour seems too selfless to work with the principle of survival of the fittest.
Why would a tree bother to send a warning signal to its neighbours whilst it was being attacked by herbivores?
Wouldn't it be better for that tree if its neighbours did get damaged, since that might leave more light and other resources for itself?
But consider this.
What if the damaged tree wasn't intentionally sending out a warning to help its neighbours, but the neighbours had evolved to make use of a warning that the damaged tree was releasing anyway?
Scientists call this eavesdropping, and it explains these results in a way that agrees with widely accepted principles of natural selection.
Any individual plant produces many VOCs when it's attacked by herbivores to signal to itself, coordinating a response between distant branches or leaves.
It is this signal, meant for communication within each individual plant, that other plants can pick up on and use to prime their own responses.
So trees have adapted to eavesdrop on their fellow trees in the forest, but perhaps more impressive is their ability to call for help during an attack from the most unlikely allies.
Terpenes are a specific group within the VOCs and are responsible for that nice tree smell you get when you walk into a forest.
These molecules are also used in tree communication in response to herbivores, environmental stress and changes to the soil microbiome.
In 2011, an experiment looked into how the European field elm responds to attacks from the elm leaf beetle with the help of terpenes.
See, the elm leaf beetle likes to lay its eggs on the leaves of the tree, ready for the larvae to feast on them when they hatch.
but the elm has some tricks up its sleeve to combat this.
They release terpenes, which seem to attract another insect, the eupholid wasp, to eat the eggs.
Like insect bodyguards, they can protect the elm from damage and get a nice egg feast as a reward.
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