Ants and Trees

Backyard Wisdom
By: Gilbert A Smith, ISA Certified Master Arborist

Like the parable of the mouse and the lion, teeny tiny Ants can protect mighty trees. The lowly worm gets all the credit for tilling the soil and feeding the trees but the ant does as much good for trees and what does it get?  Stepped on! Ants do all the wonderful worm jobs, they aerate the soil, they open up air pockets so the roots can breathe and water can reach them. They excavate 30,000 lbs of top soil in an acre of land every year which is roughly 10 times as fast as those worms. They eat insects and poop out nutrients that give the trees their vitamins. They even alter the soil PH making it more friendly for tree roots.

What would you say if I told you ants protect giant trees from damaging insects and the trees feed the ants in payment? It’s true. Ants are farmers too. In some trees the ants store the eggs of a smaller insect called “Scale” and carry it out onto the tree branches to feed off the tree. The scale insects stick their sharp sucking mouthparts into the tree and poop out a sticky sugary substance called “Honey Dew” The ants eat the “Honey Dew” which is rich in sugar from the tree. I’m sure it tickles but the tree doesn’t mind because the ants attack and eat caterpillars and other bugs that are eating the tree leaves. Remember that trees get their food from the sun. If the caterpillars eat all of the leaves it dies of starvation.

This mutualism goes so far that some species of Acacia trees actually addict the ants to the sugar from only their species so they don’t leave and farm their Scale on other trees. Like so many of us they are sugar slaves and they don’t even know it.

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