You may have tasted it already. Or, at least, you might have tried honey that was made by poop-eating bees...
While related to aphids, scale insects don’t look much like insects at all. Their body is small and flat and they have no arms or legs. You won’t actually see their body though, when you peer closely at their beech tree home all you’ll see is a long, thin tube.
At the end of this waxy-looking tube is where you’ll find our tastiest poop, which is delicious, sugary honeydew.
What makes honeydew so tasty?
Scale insects feed by inserting their mouths into the phloem of the tree, an internal tube system for moving sugar around. Phloem fluid has much more sugar in it than the scale insect needs, so it gets rid of the extra sugar the same way we get rid of waste – by pooping.
That’s why honeydew is so delicious, it’s very high in sugar. The sweet, sticky poop travels through the scale insect to form small droplets at the end that are eaten by birds and insects or fall to the forest floor.
Pests hungry for honeydew
The high-energy honeydew is an important food source for native animals, such as birds, bats, insects, and reptiles. In particular, nectar feeding birds, such as korimako, tūī, and kākā rely on the honeydew, especially during winter.
These delectable droppings have also become popular with a greedy crowd though – introduced wasps. Instead of just sipping on the honeydew as it drips from the scale insect, wasps have found that they’ll get more bang for their buck if they eat the end off the tube too. This causes the scale insect to temporarily produce much more honeydew than they usually do, which is great for the wasp. The greedy wasps will keep eating more and more, eventually killing the scale insect.
Wasps swarm through forests, and have been found to eat up to 90% of the available honeydew. This means that there is very little left for our forest birds. It’s really important that we control wasps in our forests as much as possible – a new tool called Vespex, is helping in this fight.
So there you have it, scale insect poop: too tasty for its own good.