In the case of humanity, evolution produced a organism that effectively began to interfere with or even halt it's own processes, as humans utilize technology to adapt to their environment far more quickly than the natural processes of evolution.
In the case of the Arachnids however, evolution created a race of insects that not only achieved intelligence, but achieved near-total evolutionary control. By having inherent control over their own genetic code and that of their many subspecies, the Arachnids are able to "terraform" their own bodies to suit any environment and any need... they have thus completely sidelined the necessity for technological development.
The building of the Beserker Bug was relatively simple, one merely flips the torso upside down, and then constructs the model traditionally. After this is done, additional legs and arms can be added to taste. The important aspect of the model, is that we have the large, almost snake-like fangs and jaw on the top of the creature instead of the bottom.
I originally saw a similar conversion of a Brain Bug back in 2006 or so, and in 2010 or so I created my own using simple plastic toy bug legs and some spare Tanker Bug legs. Today in 2020, I've added additional feelers, additional Tanker Bug legs, and added two small Hopper Bug arms as tiny mouth parts. Ultimately, the model is neat, but it's really the use of color changing paint that helps this specimen stand out!
The Brain Bug model remains a crowd favorite, albeit a difficult to assemble one due to it's relatively poor casting and the nature of metal models. It's too bad there isn't a good reproduction available for 3d Printing... hint hint to those who might have such talents!