Once the Nutrient Cost trait is implemented for organisms, the foundation will be set to create a more realistic Reproduction System that can apply from Microbe until the end of biological evolution. After having discussed the idea with Deus a bit, I’ll present it here.
Nutrient Cost
To recap, your Nutrient Cost represents the total molecular composition of an adult organism of your species. It’s comprised of the total amount of ammonia, phosphate, glucose, and other nutrients that constitute you. This value actually already exists in-game but just needs to be tweaked to be an official trait with a name and icon and displayed to the player.
Reproduction Cost
This represents the portion of your total constitution (AKA your total nutrient cost) that is produced during reproduction. For example, if offspring spawn with 50% the size or organs of their parent, then the Reproduction Cost of the species is 50% of the total Nutrient Cost. Another way of looking at this is that it represents the nutrients it costs for a parent organism to spawn a child organism.
Maturation Cost
Your Maturation Cost is the remainder of your Nutrient Cost to grow you from an offspring to a full adult. In the previous example, since your Reproduction Cost was 50%, your Maturation Cost will be the remaining 50% of your total Nutrient Cost.
Your Reproduction Cost + Maturation Cost should always equal your total Nutrient Cost.
Reproductive Systems
The Reproductive System you evolve determines what portion of your Nutrient Cost falls under Reproduction Cost, and what under Maturation Cost. In Binary Fission, your cell reproduces all of its organelles before spawning a fully formed daughter cell, so the Reproduction Cost is 100% and the Maturation Cost is 0%.
In Budding, your organism spawns a small bud with only basic organs. This then detaches and spends the rest of its life growing to the size of an adult organism. Therefore, in this case, the Reproduction Cost would be lower (let’s say around 25%) and the Maturation Cost would be the remaining 75% of the Nutrient Cost.
As organisms become multicellular and macroscopic, they will evolve plenty more modes of reproduction, and so this system would be able to handle all such examples.
Growth Rate
All organisms will have a Growth Rate. This represents how many nutrients the organism can “invest” from its storage into reproduction or maturation progress every second. Your Growth Rate can be affected by your mutations.
This trait actually now exists as a result of HH’s new testing Pull Request that adds passive resource absorption of phosphate and ammonia, but just doesn’t have a name yet.
Reproduction Time and Maturation Time
Using your Growth Rate, your Reproduction Cost, and your Maturation Cost, you can calculate a Reproduction Time and a Maturation Time for each organism. Reproduction Time represents the time it takes, in ideal conditions (full compound storage and no damage) to reproduce one full offspring of your organism/cell. It’s just your Reproduction Cost divided by your Growth Rate.
Maturation Time represents the time it takes in ideal conditions for one offspring/juvenile to mature into an adult, and is calculated as Maturation Cost / Growth Rate.
Summary
Such a system will handle reproduction from Microbe to Awakening. It ties the complexity/size of your organism (Nutrient Cost) directly to making reproduction slower and more expensive. It introduces a new Growth Rate trait which can be evolved to be increased if you want to grow and reproduce faster (which will need appropriate tradeoffs). It also makes different Reproduction Modes feel different, by allowing time spent reproducing and time spent maturing allocate differently based on your organism’s reproductive system.
If no one has the availability to work on such a task, I could take it on as it’s nothing too intricate (provided the agreement is there that such a system is a good idea).