I thought I would share the information I found to the community on how to get the achievement, I do not claim this is my own material. Full credit goes to Vlad at vgfaqs.com
The Lost Planet 3 Bestiary Collectibles become available later in the game, after Peyton completes a series of quests for Dr. Roman.
This specific category of Lost Planet 3 collectibles is detailed by the following guide, which explains how to tag all creatures in Lost Planet 3, what creatures you have to find, and where to find them.
At some point in the game, while playing the main missions of the story, you will receive an item from Dr. Roman. It is a pistol that allows you to tag the creatures included in the planet’s fauna.
As soon as you get the tagger, you will have to focus on tagging all enemies you encounter, before killing them. If you open the menu you will also notice that the collectibles’ section includes a new tab called Bestiary.
The Bestiary tab features 10 entries that must be filled in order to unlock the Geneticist achievement/trophy and in order to complete the side-job you get from Dr. Roman.
An important fact that you have to consider is that not all entries can be filled by tagging Akrids. Some of these entries, which require the DNA from specific Akrids, can be filled only by finding specific spots in the game.
In other words, some DNA is kept inside objects such as consoles, and you have to retrieve them as well if you wish to fill Peyton’s bestiary.
To tag an Akrid and extract the creature’s DNA you have to equip the tagger from Dr. Roman, and fire once aiming for the creature you want to tag. Next you have to aim the same creature until the marker above its head fills up, allowing you to stock the data required.
Some creatures in Lost Planet 3 are easy to tag, but others can be challenging since you are not allowed to kill them. Instead, you have to continuously dodge their attacks and wait for the tagger to fill.
Furthermore, some Akrids that must be tagged spawn only in specific areas of the planet, therefore, the Lost Planet 3 Bestiary Locations guide below, reveals the areas you have to find and the Akrids you need to tag.