About the Science: The Ven Hypothesis

I don’t know if people like or hate these posts, but I’m going to write them anyway because I learn so many cool things while writing these books. I am not an expert on these topics by any means, so please don’t cite me in any science papers. Also, spoilers ahead! Beware! If you want to read the book first, here’s the link for The Ven Hypothesis (Book 2).

Allomones and Kairomones

My favorite discovery by far this time was the existence of different types of pheromones: allomones and kairomones. As stated in the book, allomones benefit the emitter and harm the receiver. Kairomones are the opposite. They harm the emitter, but help the receiver. Initially kairomones made no sense to me, but I like to think of it like fire. If I’m lost in the wilderness, I might start a fire because I’m cold, but that fire might attract unwanted attention, like predators (In reality, if I were lost in the wilderness, I’d be a goner).

Delta P, aka “When it’s gotcha, it’s gotcha!”

The next thing I want to talk about is Delta P (ΔP), change in pressure. This came into play during the river scene with Dione. I confess, this one was more physics than biology, so not my strong suit. Not only did I have to think really hard about it, I also got some help. I’m fortunate enough to have some friends who are very good at physics who read a draft of the scene and gave me some feedback. Any errors in that scene that still exist are wholly my own, though I did my best to incorporate their suggestions to make it a little more realistic.

Delta P refers to change in pressure, and it can be deadly. Commercial divers who work in pools or dams can get trapped by the suction around drains. This suction is caused by a pressure differential that wants to equalize. If a diver swims to close and gets pulled in, their body then creates a perfect seal, and they are unable to get free.

The best way to share the dangers of Delta P would be with this terrifying video that inspired that scene in the first place. I imagine it’s a training video for commercial divers, though at 2:50 Delta P claims a different kind of victim (if you watch no other part of the video, I recommend that bit).

Success stories of controlling invasive species

For this one, I just “filed off the serial numbers” so to speak, because it’s close to my heart. This article, which called the situation the “Cinderella story of biological control,” was my primary source. Who doesn’t love an underdog? In this case, the underdog is fungus. Cinderella, thy name is Entomophaga maimaga.

In the book, Bel and Dione discuss invasive species, citing examples that were both successful and unsuccessful. Dione brings up the out-of-control (fictional) Balta moth population that was accidentally put in check by a fungus. This was exactly what happened to gypsy moths in North America. Gypsy moths showed up in the late 1800s and thrived here without any serious predator. In the early 1900s, there was an attempt to introduce the fungus E. maimaga, but it failed. There was another attempt in the early 80s, but that one also failed. After these failures, somehow the fungus was accidentally introduced around and this time it worked. There was evidence it had started killing the gypsy moth caterpillars in 1989. Scientists used “genetic and geographical information” to determine that this successful introduction of the fungus was not a result of one of the intentional attempts.

So why is this example close to my heart? As a child, these gypsy moth caterpillars were everywhere. I played with them at recess, at home, in the woods. I even remember spotting their white “tent” nests in trees as I stared out the car window. Somehow, these creatures that played a key role in my childhood (okay, maybe that’s a stretch), aren’t around in force anymore. I had never questioned it, or really noticed, until doing some research for this book, but I imagine that at some point in my childhood, this fungus reached my hometown in Virginia and decimated their population.

The article linked earlier in this section has a time lapse video of one of the caterpillars *turning into fungus, just in case you’re interested.

*Not the scientific term.

Formation of river rocks

One final thing I discovered while writing the book is why river rocks are smooth. Dione finds a smooth river rock which she later gives to Lithia. Like most people, I knew that water caused rocks to become smooth over time, but I didn’t understand how. It’s not the water itself that causes the erosion, but the sediment in the water. When these particles hit a rock in a river, they break off tiny bits of that rock. Over time, this causes the rocks to become smooth.

Well, that’s all I have for this one! Hopefully you learned something, even if it was just one of the little known perils of being a crab (courtesy of the Delta P video).

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