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Wingworm brains. They're on my mind tonight, since the cephalization of saucebacks (which also needs to be discussed) made me think about it.

Wingworms are pretty weird. They see on one end and eat from the other. The cephalic implications of this have been ignored by some, but not by others. This has resulted in a rather inconsistent setup that calls for some kind of solution, so I'd like to propose a description of the wingworm central nervous system.

So, wingworm brains...cannot be in the sauce. At least, not purely. This is because of the delay between input from the eyes and the signal actually reaching the brain. They about have to be abdominally cephalized, which means that flying backwards is actually ideal for them. However, some species still fly forwards and even gain mouth-end eyes, which would imply they have a mouth-end brain. To reconcile this, I would like to propose a sort of two-part brain which is specialized more one way than the other depending on the species.

Wingworms would in effect be said to have two brains (though when extracted it would look more like one continuous organ), one of which is the "fast brain" and the other is the "slow brain", referring to how quickly they respond to visual input. The fast brain would contain the equivalent to the frontal lobe for a given clade.

In species with sensory organs only in the front, the mouth end bears the fast brain while the abdomen bears a spinal cord-like slow brain, as one might expect. Pretty standard cephalization.

In species with eyes on their back but which still move mouth first, the abdominal brain would be the fast brain, allowing them to take off running far faster than you or I could at the first visual sign of danger, while the mouth end would bear a slow brain that aids in choosing direction of movement to pass on to the fast brain.

And in species with eyes on their backs which also fly backwards, likewise as expected the abdominal brain would be the fast brain, while the mouth-end slow brain would be very spine-like in complexity and mainly serve to help get the mouth around food.

And in species with more mixed traits, like eyes in the front and back, they could be said to have two fast brains, but I suppose the one corresponding to movement direction would be more complex and do more logical processing. It could vary some though.

I think that optimal wingworms which retain eyes on their backs would be best off flying backwards, and likewise having an abdominal fast brain and a simple cephalic slow brain. Though convenient, moving mouth-first isn't technically necessary and a backwards life was destined the moment their ancestors put eyes on their backs to watch for danger from above.

Thoughts?

I'm not very familiar with the topic of cephalization, but from what I know, this seems like a sensible compromise.

I'd been reading into this lineage recently. It seems many species have eyes all along the back, including the earliest ones.

To me, this doesn't suggest a cephalized starting point, but maybe something like a system of repetition and redundancies that could have had advantages for very quick but very simple processes.

What about - as a starting point - distributing the brain into segments along the nervous chord? Earlier cognition could have consisted of avoiding certain colors and being attracted to certain colors. At which point the first segment to see would be the first to send the signal along the body. Cognitive functions could have developed along the connective tissue between segments. I.e. Two eyes deciding the distance of a potentially yummy purple spot.
Over time, these highways between brain segments allowed the build-up of a hierarchy of higher cognitive functions, such as spatial awareness or object recognition or identifying the flight pattern in pursuit of prey, and those would be the ganglions to trend towards one another in one of the body ends and undergo partial cephalization, as redundancy for higher functions would be more costly.

The end result could be a general trend toward anterior or posterior cephalization, while also allowing for localizes systems along the way. Those can include both input and output. For instance, maybe the species with bat wings could have a central flight ganglion that merely receives desired vectors and acceleration stats from a front ganglion.

Rather than describing them as fast vs slow, I would reserve fast for functions where a ganglion or a segment has the authority to send an instruction on its own, and slow to describe functions where consensus between multiple cognitive systems is needed.

I.e. Even if its mouth is in its posterior, let's say the Uniwing, the decision to spit out something that tastes bad is fast, but the decision of determining if it's safe to land on a fruit can be slow.

P.s. Maybe anal cognition vs oral cognition can be used instead ?

This post has been edited by Jarlaxle: Jan 10 2023, 08:27 AM

I described the butt-end brains as abdominal because it wouldn't necessarily be all the way at the back. I was imagining a fairly elongated brain due to the spread of the eyes.

To my understanding, cephalization happens quick once a primary means of sensing the world evolves, which usually means developing to support the eyes.

I must ask, why exactly do they need a mouth-end brain initially to develop eyes at the front and not simply develop a ganglion after the eyes become advanced enough to require it? It isn’t like sea snakes have a brain in their tail to support the light-sensing functions of it, though admittedly they don’t have full fledged eyes there so that may be a considerably different situation, but, still worth note I think.
'Seeing' tails help sea snakes avoid predators

This post has been edited by Oofle: Jan 10 2023, 12:12 PM

That's not really what the subject of this thread is about

This brings up if the red tissue is actually segmented initially in their lineage, I know that it does appear to become segmented later on.


I like the idea of them having just a string of ganglia down their length that then Branch out to control different particular parts, possibly having this derive from sense of touch initially.


I'd say that having a ganglion specific for Wing control makes the most sense, rather than just for the bat winged varieties.


Having these ganglions secondarily become larger and more brain-like growths along their length based on where their primary mode of sense occurs, makes a lot of sense to me.

You could also have each eye get a single ganglia for processing the input, and then have those feet into a long cord beneath them which is non-segmented and that length would be the thing that actually creates an image and processes what the organism needs to do in response to the stimulus.

So the main problem I see is that externally, cephalization didn't happen to wingworms: The sensory apparatus didn't evolve on or migrate towards one end, the eyes are spread along the back and are far away from the taste & scent, and shifting directions of motions seems to be incredibly easy for the lineage as a whole... which makes it kind of awkward to enforce internal cephalization. already you have to start with the compromise of two brains and one is more than half the length of the body... is that an artifact of cephalization, or a lampshade that pulls our attention to the lack thereof?

It's kind of like a cookie with candles on a birthday, rather than making the other kids believe that the cookie is a cake, it is more likely to get them to notice that there is no cake, raising the question... what happened to the cake? And what's the thing in the kitchen on the tray with a hole the shape of dads face? Mysteries that demand one's attention.

IMO, if we want to arrive at a working evolutionary story for wingworms, maybe we should try to answer that question here - within the in-world context - why didn't wingorm cephalized?

What kind of developmental constraint could have prevented it from being the go-to development it tends to be elsewhere and favored the spread-out sensory development we see in its evolutionary history?

I figure having eyes on the back kinda destined them for strangeness in the cephalization department. Having their sensory organs and presumably a brain so close to their legs allows them to react to threats far faster than if they were more separated, like having a hot stove level reaction for visual input. As small creatures that are prey to everything, keeping this setup for the sake of rapid reaction time would have been advantageous and it's possible that more cephalized individuals largely ended up getting eaten. Cephalopods have been prevented from going freshwater because they'd have to lose their lightning-fast reflexes in the process (as it depends on saltwater) and they can't afford to; the same could be the case for brains in basal legged wingworms.