In my own campaign world, in many regions, I have large populations of Giant Insects. With some thought, I have considered the wider impact of such populations of Giant Insects on the surrounding natural environment, as well as community settlements.
Was this thread inspired by this article: "Concerning Growth In Number Of Giant Flies As Adventurers Keep Slaying All The Giant Spiders"
https://babylonbee.com/news/adventurers-slay-giant-spiders-and-now-the-land-is-overrun-with-giant-flies
“This is why I hate adventurers,” said the unnamed man who runs the inn in the nearby town of Wolfwater. “They just see some ‘monsters’ and say, ‘Hey, maybe if I kill that, I’ll get some good experience, and perhaps it will drop some gold.’ And they never think of the long-term consequences.”
Greetings!
*Laughing* That's a in article! I like it, but no, I hadn't seen that article until you posted it. I have had Giant Insects in my campaign world forever, and was doing some thinking on how such a reality may affect the surrounding environment--namely, what kind of impact would the existence of several varieties of large, unending numbers of Giant Insects have on local Human communities, as well as communities of other humanoids?
I of course thought of food. People currently eat all kinds of insects around the world, from Grasshoppers and Beetles, to Ants, Snails, and others. So, I if Giant Insects were around, they no doubt would go on the menu quickly.
Then, I also thought of Giant Insect resources, like their chitin, hides, eyes, stingers, wings, legs, mandibles. All of those such things, being Giant-Sized, would no doubt be utilized somehow in the crafting of clothing, armour, or weapons. So, there would be a market developed there, for certain. There are also some considerations on the kinds of impact that Giant Insects would have also on the maintenance of agriculture, commerce, roads, border security, all of that. Giant Insects swarming about would it seems increase the likelihood of an increased militarization of any Human community, or group of humanoids. Communities simply must have a vigorous force ready to defend the community against a large attack by Giant Ants, or a rampaging Giant Beetle--or a hal dozen or dozen Giant Flies moving into the village. I have easily swatted and killed over a dozen flies working in my garage, and I can tell you, having even a decent number of normal flies around you is constantly annoying, and disrupting, to the point where I had to stop doing what I was doing, and focus on killing a doen or so flies. I just imagine, well, things would be very different if the Flies weighed 300 or 400 pounds, and were the size of a hog! *Laughing* That, I imagine, would certainly make them potentially lethal in their attacks, particularly being bit by such Giant Flies more than once.
Plus, I have a dozen Giant Fly miniatures in my collection of miniatures for D&D. They are 32mm, and are on their own clear *flying stands* so they definitely come in handy. The Player Characters often encounter them everywhere, which is nice, too, for keeping the Player Characters on their toes. Giant Flies, being hungry, belligerent, and absolutely stubborn, stupid, and heedless of any danger to themselves, can be encountered anywhere. In the middle of the town, out in the countryside, inside dungeons, sewers, wherever. Flies go anywhere for food, and attack relentlessly. Other kinds of Giant Insects are also interesting, too, and insects pose a different kind of threat than humanoids, or even other kinds of monsters. Insects, being prolific in their breeding, are likely to have seemingly endless numbers, so the Player Characters will never likely "Get Rid of Them". The Giant Insects are an opponent and threat, but also almost like an environmental condition. They can sometimes be defeated, for a time, but they will be back. Then, of course, Giant Insects, much like normal insects, hate humanity and seek to annoy, disrupt, bite, sting, and eat us at every opportunity. And, as many insects are also absolutely fearless, they charge forth, heedless of any danger to themselves, so Giant Insects make excellent combat opponents that need no other kind of explanation. They do not need a rationale, nor do the insects worry or experience fear. They eat, and attack anything they detect in their territory. Giant Insects are also immoral, and remorseless. They view eating Human men, women, children, all as equally tasty, so anyone is likely to be jumped on and ruthlessly attacked. Giant Flies for example, would absolutely terrorize women and children being outdoors. Men, farming, fishing, woodcutters, or doing whatever, would also find that Giant Flies would be dangerous, and a threat. I can just hear the women and children screaming though! As an aside, you no doubt are familiar with how women absolutely *shriek* currently whenever they encounter a spider...or God forbid, a snake...*laughing*
So, I see many interesting uses for Giant Insects in the campaign. They serve as a constant threat to people everywhere, but in a somewhat different manner than monsters or humanoids. The Giant Insects serve as a reliable food source, and impact local diet and cuisine. Then, of course, Giant Insects are also resources themselves, supplying bodies, ingredients, pincers, stingers, and so on for clothing, armour, weapons, and alchemical uses, too! Thus, I think that Giant Insects are a fun and rewarding addition to virtually any campaign.
Semper Fidelis,
SHARK