Plausible homeworld for an insectoid-ish alien species?

Question

I have a planned species of aliens that have many commonalities with longhorn crazy ants (cooperation with colonies of the same species, can live in a large variety of environments, and have the ability to have genetic variation with a low number of breeding pairs). They are humanoid bipeds with exoskeletons as well as pseudo-endoskeletons, lungs and hearts to pump blood, and regulate heat by a series of capillaries in their mouths (basically just panting like a dog). Individual physical power, as a whole, isn't that much more than a human.

Socially, their "family" units consist of a female queen, a male drone, and twenty to fifty sexless workers (depending on the sub-species). Its like if an entire tribe operates as a single organism, while all having independent minds. Finally, they have the ability to cooperate with other families to form cities, nations, and empires. After a few millennia of advancement, this species took to space.

My question is: what kind of home-world would this species evolve on? Even with my additions to make them environmental generalists, I got no idea how human-sized insects could exist in the first place. I would love to be able to include details about native cuisine and interesting animals they might take with them to space, but at the moment I'm stumped.

Answer 1

For starters, the idea that your species is insectoid is a good one. In our own world, insects are capable of evolving relatively fast, when compared to other animals. Due to this, no other group of animals is more varied than them. From Wikipedia:

The total number of extant species is estimated at between six and ten million; potentially over 90% of the animal life forms on Earth are insects.

For comparison, there are less than 5,500 mammalian species.

Your species has evolved heart and lungs, so the square-cube law will not keep them from achieving a humanoid size. The atmosphere they live in can be similar to ours. They would evolve to have a size close to a human simply to fill a niche in evolution - other species in the same planet could be as large as elephants, or even dinosaurs, because large sizes can be an advantageous adaptation in some environments.

Having an exoskeleton can make some things easier, and some other things harder, when compared to our own lifestyle. There is a lot to be said about this, so I will refer to a previous question about that:

Would a humanoid insect species even lift?

A pseudo-endoskeleton can remove some disadvantages mentioned there, or probably remove all disadvantages if muscles can attach to it.

As for food - there are many species of ants that are omnivore, so there is nothing keeping yours from being omnivore as well. It can eat whatever you can come up with.

Finally, as for interesting animals they might take to space:

• giant aphids for food - those would be to them like cows and pigs are to us;
• Anatomically correct arachnes as companions (or slaves, if the master species is evil);
• Any animal you can think of as pets. It would be interesting if they had, for example, large dragonflies in bird cages, or giant beetles on leashes.

Answer 2

Your world would probably be very jungled in order to create enough oxygen for them. The waters more mineral rich for exoskeleton development. Their exoskeleton could have evolved to be more like the plates of an armadillo or other plated animal in order to accommodate increased heat stresses and allow for lung breathing. When I think of insectoid aliens I think of District 9 a lot. They were more exo/plated then exoskeletons. The same could be true for other indigenous insect life on your world. Another reason for jungles is because most insect species on our planet live in jungles, like 90% I believe. Plenty of food there as well. You may also want to explore with the idea that their world has a lot of equatorial coastal environments. Where there is a lot of coastal shelving, atolls, etc coupled with jungles. This would be a little more Alien, provide plenty of food, both from the jungle environment but also coastal providing more mineral rich waters as well. Have the interior of your continents be more barren with lots of mountains to feed into those waters. Or have very large fresh water environments, scattered all over the planet connected with rivers, again more jungles, but few mountains or deserts so very little plate tectonics action going on with that one. The northern and southern regions of your world in this scenario would be where are more mountains, barren locations, or just plain oceans with icing. Your world doesn't need to be as watered as ours. Most people think water means lots of life but our oceans are more like water deserts, very little biological life except at the coastal shelves. So you can play with that concept a lot more if you want. If it's a river world with lots of flowing water a moon wouldn't be necessary. If coastal areas then yes for tidal life to develop and flourish. Planet size can be the same as ours, less if full exoskeletons, bigger if plated with hollow internal skeletal structure. I hope that all helps.

Answer 3

Well for a successful exoskeleton species I would say planet with lighter gravity and mineral rich waters, and a planet like this could be an interesting contrast to earth, where support for arthropod-like would be stronger than creature with just a mere endoskeleton. The arthropods could grow large and compete, while any endoskeletal creature would likely be reduced to the role that insects have on our planet. Because even with the lighter gravity their is a limit to the size of life, and the endoskeletals will either hollow out their bones like the dinos to support such a large stature making them still weak compared to the armored up ant people. think of an ant vs an etrusken shrew. And still their is another problem, mitochondrial density(or the alien equivalent) will heat up the bodies to much causing them to melt into a hot goop. So to solve this large animals have lower amounts of mitochondria and have them work just enough to keep the creature running. But it can only do this so much because to keep the cells running the creature needs a certain amount of them working to be alive.

Answer 4

From the wikipedia description this ant is very very adaptable and seems to live in many different conditions even out-competing other species. So I'd say, you have a certain liberty in choosing the habitat you want. Hover, keep in mind that large creatures (sort of large "versions" of current animals) need more oxygen than their smaller counterparts. I'd make your planet/habitat VERY rich in oxygen, and quite abundant in food.