Chapter 65

"How so?" asked her twin sister, Mia.

"As near as he can make out – he explains that the sample is only part of the tree, and the borers tracks move out of the sample, so some of this is supposition after examining a whole series of tracks – he surmises that the creature makes some sort of change in its metabolism, and becomes a pre-adult with a target and new powers. NOW, it can enter other tunnels, and by some means (he assumes by pheromones) it gets the creature at the end of that tunnel to reorient itself towards the bark of the tree. Probably it can smell the bark, he presumes."

"Sounds odd", said her husband Robert. "What is it up to?"

"He assumes this is preparation for emerging from the bark. It uses other borers to make an exit tunnel for it, so presumably at this point it cannot do its own boring, but must still be the size to use the tunnels."

Helen had a question. "That sounds a reasonable assumption, but what happens when the grub (we'll call it that) reaches the bark? It won't want to enter the bark, will it? And it will still be blocking the exit."

"Ha! This is where our researcher gets clever. He reckons that the pre-adult then EATS the grub from behind, for sustenance before leaving, and that gets it into the bark. He claims that the pre-adult will sit in the soft bark until it feels ready to leave – possibly grow wings I the meantime. Of course, WE know what it is doing, wings or not: it is checking the temperature, so that it doesn't emerge when it is freezing outside!"

"Fascinating," declared Robert. "Presumably the insect emerges as a small version, and grows as it puts on weight. I expect they would all emerge at the same time, and mate, before laying their eggs on the bark of another tree."

Helen had her brows furrowed, still puzzled. "Why do the borers never intersect each others' tunnels? You didn't explain that, Mya."

"Yes, but the researcher did. The borers all lined their tunnels with a chemical which has a pungent smell, so that any approaching borer would detect that and avoid it. Simple! He was dead chuffed to discover this chemical, as he reckons it has uses as an insect repellent on Earth, and he and his colleagues are trying for a patent for that purpose. If it gets the go-ahead, and proves effective - as he expects - it will be worth a fortune in itself!"