Insects and crustaceans are the two most prolific groups of animals on Earth in terms of species. Insects are mostly restricted to land and freshwater and crustaceans are mostly restricted to the oceans. But those restrictions are obviously out the window in Mutant Future. Even though both are arthropods, there are some significant differences, ones that should have an impact on game play and setting design.

Most insects have wings or a winged morph in the case of ants, termites, some aphids and others. Even if the PC doesn't have Complete Wing Development, it should have an ability to climb easily and even adapt to low or no gravity much easier than a vertebrate (an enhanced version of Increased Balance). Though most insects have eyes and "ears", their main sense is chemoreception- a combination of taste and smell. Increased Taste and Increased Smell are musts and Fragrance Development is strongly suggested (they have to produce odors if they communicate with them). Because of their strong sense of chemoreception and eye structure, their sight is significantly weaker than a vertebrate. At least in terms of seeing stationary objects- they detect motion much faster than we do. Vision Impairment, Increased Dexterity and a 1 point bonus to intiative checks are the best way to represent this. Insects have one huge negative aspect for playing a PC- they don't heal very well. As they do not molt as adults, unlike crustaceans, they have no capacity to regenerate lost parts like legs, wings and antennate. That means PC mutant insects must have a healing mutation, otherwise they are not viable. Monstrous insects should either have a healing mutation or be easy to kill- just pierce their exoskeleons and wait for them to bleed out. Not all insects have Aberrant Form (natural weapon), but those that do are usually restricted to bites or stings. Mantids and mantisflies are rare exceptions. Toxic Weapon is found among insects that eat poisonous prey (usually plants) and reuse the poison in their own sting or flesh or manufacture their own. I have no idea how many kinds of poisons there are in real insects, much less mutants.

And that is all in addition to whatever mutations the Mutant Lord allows. Six musts (Increased Balance, Increased Smell, Increase Taste, Increased Dexterity, Vision Impairment and a healing mutation) is a lot but then, most of them are not super powerful mutations either. Note that most of these also apply to arachnids- spiders, mites, scorpions and their allies.

Crustaceans have their own strengths and weaknesses. They can regenerate lost parts, but only when they molt. Depending on the mutant, this could be weekly or annually. In any case, molting should take 6 hours to perform and the mutant is helpless in that time. For a limited period thereafter, the mutant's exoskeleton is weak and needs to harden- cut strength and dexterity scores in half and ignore Natural Armor (if the mutant has it) for that time. The healing aspect of molting should be restoration of all hit points as well as any additional ones due to level gain (the lucky mutants that roll a constitution increase). One advantage molting can provide that is not an existing mutation is the ability to modify the parts regenerated. This can be represented by a lot of different physical mutations, sort of like the xenoshrimp in Creatures of the Wastelands. As creatures that are water dependant, even land based crustaceans (some crabs and pillbugs) need a lot to drink. For mutants, this is five times the amount of a human of the same mass. They may also have Epidermal Dependance (water) if they are a normally aquatic species like shrimp or crayfish. Their Aberrant Form (natural weapon) is usually claws. In fact I can't think of a single species that uses its bite in prey capture. There probably is, but I can't think of any. And obviously all crustaceans should be able to swim and breathe water. I wouldn't bother to list this as a mutation, just a species trait.

So they have only four or so musts (Regenerative Capacity for molting, Aberrant Form (xenomorphism) for modifying regrown parts, Epidermal Dependance and Aberrant Form (natural weapon)). Their strengths and weaknesses are so very different from insects, something the player and ML should play this up.

Any questions?