So, are aliens intelligent anyway?

[tobsimon]

I think biters should be like ants.
Ants are far from brainless however. Their behaviour is motivated by ensuring their personal and their colonies well-being. This relates to what MalcolmCooks wrote. More importantly, it leads to a conflict: Avoid direct harm but attack threat. I think this needs to be modelled for the biters, to make them more believable (and less stupidly suicidal) creatures. I fleshed out some ideas in this topic (shameless self-advertisement) hrere: Fear inducing alien behavior

[MalcolmCooks]

Perhaps the biters can be something like this: each nest (by which I mean cluster of spawners + worms) is actually a single intelligent organism based underground. Spawners and worms are actually part of the nest entity's body. The biters and spitters are themselves dumb insects, but follow orders given by the nest entities. That means you can engage nest entities in diplomacy (maybe after doing research that lets you discover the true nature of the biters).

But why should evolution create that?

Well I have thought about this now. On earth there are actually similar organisms, for example the Portugese man o war, which is actually not a single organism, but a colony of connected organisms who have different roles. From National Geographic website:

The man-of-war comprises four separate polyps. It gets its name from the uppermost polyp, a gas-filled bladder, or pneumatophore, which sits above the water and somewhat resembles an old warship at full sail. Man-of-wars are also known as bluebottles for the purple-blue color of their pneumatophores.

The tentacles are the man-of-war's second organism. These long, thin tendrils can extend 165 feet (50 meters) in length below the surface, although 30 feet (10 meters) is more the average. They are covered in venom-filled nematocysts used to paralyze and kill fish and other small creatures. For humans, a man-of-war sting is excruciatingly painful, but rarely deadly. But beware—even dead man-of-wars washed up on shore can deliver a sting.

Muscles in the tentacles draw prey up to a polyp containing the gastrozooids or digestive organisms. A fourth polyp contains the reproductive organisms.

There are lots of other marine animals like this as well. So we know it is possible for evolution to create such a system.

So let's say the biter nests are like this too: the spawners and worms are each seperate organisms, but cannot survive on their own, like the organisms that make up the man-o-war. The nest queen is underground and has many tentacles that connect the spawners and worms. Biters are there to bring food into the spawners, and also for reproduction, because they can create new nests.