⚜ SteamCozy

Home / News / Thrive

Devblog #53: The Birds and the Bees Update

Thrive · Community Announcements · August 30, 2026

Read the original on Steam ↗
The time has finally come for Thrive 1.6, the third major update to the Multicellular Stage! So how come it's called 1.6? Three months have passed since the last major update, and a lot has been added in that time. So much, in fact, that everything in our roadmap planned up to version 1.6 was completed.



Included in this update are two new reproduction modes, Sexual Reproduction and Mass budding, both in different way playing with the mechanics for having different cell types in one species. We also have the new Actomyosin Organelle that lets you create "muscle cells" which allow for large, yet fast and nimble Multicellular organisms. Stretching the membranes of individual cells makes Multicellular creations look much more cohesive, and auto-evo is now creating new AI Multicellular species! All in all, the Multicellular Stage is now much closer to what we expect its final form to be.

We would also like to remind people that our second community art contest is ongoing. Art from this contest is to be used as Thrive loading screens and/or Juuzo Lenz's Thrive-inspired speculative evolution series. The winner of the first contest was added to the game in this update. Art of all levels and diversity of quality is welcome!

Thrive 1.6.0




▶ Watch on YouTube



Reproduction Updates





The namesake of this blogpost is one of the updates to our reproduction system: the addition of Sexual reproduction. When you choose this option, you will no longer be able to go directly to the editor when fully grown. Instead, you will have to launch a gamete cell and have it merge with the gamete cell of another member of your species in order to open the editor. As a reward for your efforts, you will receive a 20% discount on all MP costs in the editor. Initially, you can select any one of your cell types to be used as a gamete, but you also have the option to switch to anisogamy, where you can design two different gamete cell types. At that point you can also decide which of the two "sexes" you want to play as yourself.

As finding a mate can be challenging, we included some functions to make it easier. If you also have Signalling Agent available, you can use a command to call a mate towards you. With the right difficulty settings (enabled on Normal), this will spawn one in and point them out to you if none exists yet.

But that's not the only new option in this menu. Another addition is Mass Budding, which simply allows you to start the next generation with multiple cells instead of only one. A slider allows you to control exactly how many cells you want to start with, following the same order as the growth order you can set in the editor. This way, you no longer need to make sure your first cell can survive on its own. Of course, there is a cost to this. The larger the bud you want to start of with is, the more resources you will have to gather before you can reproduce.

Finally, the already existing reproduction mode Sporulation received an update to how its selected cell type works. Instead of using one of your normal celltypes, upon first selecting the sporulation reproduction mode you are now prompted to select one of your existing cell types to have it's design copied to a new and exclusive spore cell type. This cell type can then only be edited from the reproduction tab and cannot be placed in your normal body design. It is likely we will want to apply this same system to sexual reproduction later on.

Actomyosin





A new Multicellular Stage organelle, Actomyosin allows you to create a type of "muscle cells". In exchange for their significant size and an ATP cost, these greatly improve both the movement speed and turning speed of your species. As you can only place one Actomyosin per cell, the only ways to improve the speed you get per cell are to improve their specialization, and/or place them adjacent to other cells of the same type. The tuning on this new feature is quite strong right now, so it is an ideal way to keep your large multicellular species mobile!

The design of the organelle represents an arrangement of actin and myosin proteins found in "simpler" types of muscle cells, similar to what we still see in smooth muscle tissue (used for example to make your blood vessels and digestive system constrict). These actin and myosin fibres actively slide past each other using energy from ATP, causing cells, and on a larger scale whole tissues, to contract. We represented this sliding method of contraction in the organelle's model and animations as well.

Actomyosin is also the first organelle that comes with membrane type restrictions: As constricting while pulling on things outside the cell is rather difficult when the cell has a rigid cell wall, Actomyosin can only be placed in cells with Normal or Double membranes. This is the first of what we hope will be a larger array of differences between membrane types, creating both clearly different groups of life and offering more meaningful choices to players.

Multicellular membrane stretching





A quite consistent complaint about the Multicellular Stage has been that creatures often end up look like a disconnected swarm of cells than a real cohesive body made of cells. There have been a lot of different ideas on how to solve this in the past, but one of them is bearing fruit: membranes of cells that are close enough together will now stretch out towards each other. This makes things look a lot more cohesive. The effect is particularly noticeable when you have cell types of different sizes and/or shapes, because these can usually not be placed close together.

This is also not just a cosmetic change. The stretched membranes have collision as usual, so things will bounce off of them. In particular this should reduce occurrences of another common complaint: small cells slipping through the gaps in between cells and getting stuck inside you.

We're quite happy with how this has improved the body of multicellular species, but it's likely we'll continue experimenting with the exactly shape of the membranes generated.

Multicellular auto-evo





Finally, our evolution systems are now working on Multicellular species. This means that other multicellular species will now be mutating, migrating and diverging right along with you. Your own multicellular species' population will now also depend on auto-evo's evaluation of its performance. The mutations added so far cover: adjustment of environmental tolerances, changing of behaviour, creation and placement of new cell types to add new organelles to, and removing organelles from existing cell types. There are still some obvious things missing from this list.

For example, the system will not yet be adding organelles to existing cell types. Another missing feature is for AI species to become multicellular on their own, so for now the player will always be the first, and all AI multicellular species will be descended from that species. There are also some limitations on how auto-evo decides what is effective. For example, it will decide a pilus you place on the front of a cell is useful, even if that cell is at the back of our species. These and many other areas will be added to and improved upon in future updates.

Additional Features







A full list of changes is available at the end of this post.

What’s Next



With this update the Multicellular Stage has taken a big leap towards being a complete experience. As the 1.6 designation indicates (in the way we number our releases), with this we're over half way in our implementation of what we consider the "core required features" for the Multicellular Stage. With that in mind, we are still confident as well in the completion of the Multicellular Stage around the end of this year.

Considering the size of this update and some earlier reports, we anticipate having to spend some time after release fixing up bugs. Looking at our Release Roadmap, after that we will likely likely work on features such as mechanics for nerve cells and then adding size-related costs to Multicellular species (which is meant to make using specialization and adjacency more important). We will also have to evaluate whether there is enough time for optional mechanics like "non-cell parts" (things like shells).

Join us a bit later today for our developer Thrivestream where we'll celebrate the release on the stream, but also answer the usual question of what's coming in the next releases. You can visit our feedback thread to give your thoughts on this release.

Watch the stream:


▶ Watch on YouTube



Patch notes



Thrive MORE ON STEAMCOZYThrive 92.5% positive · 1,327 reviews Price tracking · player charts · similar games →

This announcement was written and published by the developers/publisher of Thrive on Steam; it is mirrored here unedited for readability, with full credit and a link to the original above. © the respective rights holders. Rights holder and want it removed? Email us — we take it down promptly.