Your last point is one that I have to seriously consider. I can write around your earlier issues just by making the insects phototropism instinctive rather than intellectual. Once the light is gone, so is their attraction to it. Similar to what happens when you cut the juice to a bug zapper. The bugs stop landing on it even though it is now a perfectly safe (if dark) perch. On your "things easier to do..." point, I will definitely give that some thought. I have accused other authors of that sin often enough and I don't want to be a hypocrite. Thanks! +1

The star goes out, when the insects get close enough that they no longer see it they're stupid, they simply go after another star.

Your argument stems from the assumption that long-term memory is a prerequisite for an advanced civilization. I'm not sure that it is.

@LorenPechtel there's a disconnect between "so dumb they forget about you when you turn the light off" and "so powerful they can wipe out K2-level civilisations"

@MooseBoys they clearly spend years, decades and possibly longer navigating between stars looking for food, and have the technological and strategic intelligence to defeat extremely powerful and advanced spacefaring civilisations, possibly of multiple different species which may have radically different models of intelligence themselves. The bugs can't be dumb. Its also difficult to accomplish all those feats without remembering a bit about what happened during your last mealtime, years, decades or centuries ago.

@StarfishPrime Isn't the sheer number of insects a danger in itself? What could a K2 civilization do if insects with simple swarm intelligence, a size from ants to elephants and their swarm larger than an entire galaxy? As the insects can devour planets, it would also be possible for them to eat any kind of defense facilities. So the swarm is attracted by a star and can also be tricked simply by turning off the star so they choose another star as their target. But once the swarm has arrived at an active star, it should be almost impossible to fend them off.

"suitable stealthiness of the fleeing world"... um, good luck with that.

Agree with @sirzento - a large enough solar mass has the capability to destroy a star and K2 civilization, but I wouldn't call it particularly smart. Similarly, these insects don't need to be smart, they just have to have a mechanism that allows them to overwhelm the defences such a civ could present. That could mean the insects have stupidly large numbers, or the ability to evolve to counter weaponry, or to phase between normal space and a different dimension to avoid damage.

Even a modern soldier couldn't do much against 100 billion ants. PS: in my last commend I meant size of a whole solar system, not Galaxy :^)

@sirzento if the swarm is the size of a galaxy, all bets are off. But for smaller things, there's always nicoll-dyson beams, beam-driven projectiles (possibly relativistic), autoreplicating counter-mechanisms and so on, especially given the multi-years-long timescales involved.

@IanKemp I like that you took issue with "stealthiness of the world" and not "reactionless drive" or "the entire concept of just turning of a star" ;-) And seriously, did you just complain about stealth, and then talk about "phasing into a different dimension"? Dude.

@sirzento a modern soldier is not equipped to destroy ants, but a thorough bioweapons program certainly could. Use the right weapons for the right task.

@starfish Think of locusts in our world today. Mostly instinctual, wrecking havoc, but the result of eons of evolution. If they were engineered by a K2 civ, they don’t have to be intelligent themselves.

@SRM they need to be intelligent and powerful enough to evade, subvert or destroy the weapons of another K2 civilisation. If they're dumb, they're too vulnerable to spoofing, subversion or destruction themselves.

@starfisprime They may have that weakness. Designers may not have worried about another K2 (“We are older than anyone else, and far ahead”) or may not have thought of that. Or this is a runaway process not doing its intended task. Plenty of room to allow for the instinct-only bugs.

@SRM the problem is that it has become an idiot plot, that relies on dumb people (who are allegedly super-duper advanced, very old and very powerful) making half-arsed devices for ridiculous reasons, when they could have trivially done a good job. I'll suspend my disbelief for soft and pulpy scifi and space opera, but I draw the line at idiot plots.

(Before anyone tries to draw real world parallels with organisations cutting corners, the US military is out there using unmanned drones controlled via the internet launching hellfire missiles at people tracked by their cellphones, who haven't the slightest ability to defend against that sort of force or to realistically fight back. They don't fight fair, or send out their old, cheap weapons to do the job. If you have an overwhelming advantage, you use it)

@TracyCramer no, people are trying to justify a creative decision with idiot plots. Have a think for a moment about the difficulties of engineering a self-replicating, world-eating, self-propelling interstellar plague. Now have a think about why you'd make it mind-bogglingly stupid for no-apparent reason, when with your incredible technical and scientific know-how, making it not stupid would be trivially easy. That's where the idiot plot sneaks in.

We are already mapping the stars: sci.esa.int/gaia Any advanced civilization would also know the planets that are orbiting each star and the composition of their atmosphere.

@TracyCramer I'll also point out that the common cold isn't a perfect counterexample either; look at the number of viral and bacterial diseases we can prevent or have outright destroyed by way of vaccination, a relatively young and primitive technology which will likely get better with time. The cold virus also isn't a particulary serious threat to most of us.

The term "swarm of insects" conjures an image of non intelligent creatures for me. Your answer seems to be that you believe that these insects need to be intelligent to be enough of a threat, but you never actually mention that in your answer (you just assume they are intelligent without explaining why).

@ventsyv, the OP says the beings warning us are intelligent. He never said the swarm was intelligent. One can assume that of course, or one cannot. Justifying either of those scenarios is up to the OP.

Also, in the comments, you seem to conflate "I don't know how to make that plot work" with "it'll be an idiot plot". You know, perhaps these weren't weapons but were supposed to simply harvest a star and then return home with the spoils, but due to a programming error ended up building more with the spoils and going after the next star. Or perhaps these are creatures that evolved on one sun and gained the ability of interstellar travel somehow. Or they lived peacefully in the interstellar void until some event changed one of their abilities or their numbers. Plenty of options.

@Jasper insects aren't stupid. You don't see swarms of locusts flying out to sea and drowning, do you? Lack of intelligence does not imply stupidity, implausibly broken evolution or poor design.

I never used the word stupid. I would say that creatures acting on instinct instead of intelligence do have less of a capability to deal with new situations. Thus, an instinctual creature's reaction to a food source disappearing being that they go for the closest food source they can still "see" (which is basically what they were doing all along) seems more plausible than them discerning intelligence and checking it out to see if there's food of a type they have no experience with to me.