The nature of animal life versus robotic life.
By questioning whether or not robotic life could ever count as animal life, Lem raises a philosophical question about whether robots count or not. In this instance in particular, that question is intensified by certain attributes of the small robotic animals. For instance, they detect threats and flee in a swarm, just like animal insects. They also can procreate and have developed their own evolutionary timeline. Lem is intentionally blurring the lines between animal life and robotic life.
Technology may not be as controllable as we originally thought.
The humans are making use of space travel when we first meet them, a great technological feat to be sure, but they quickly realize that the true potential of a technological world far surpasses their assumptions. All that needed to change was that the robots could self-replicate like a biological life form. After that, the robots became as a living being, and the only choice the humans are left with is to consider nuclear warfare. With one small adjustment, the robots become uncontrollable.
Horror in sci-fi.
The genre of science fiction sits somewhere between fantasy and horror, and in others of Lem's works, like The Cyberiad, he shows a humorous, light-hearted approach. In this story, Lem shows the horror element of scientific speculation. The horror elements of this story are that they're on an alien planet, that there are alien lifeforms that are simultaneously threatening and beyond the scope of the human's understanding. This is the core thematic implication of the horror genre—no one knows what could happen. By speculating, the reader is asked to participate in the fear of the unknown.
The value of open-mindedness in speculating about the future.
During the late '50's, when Lem was working on these stories, ideas like hive-mind electronics were still decades in the future, and yet, he accurately predicted the development of semi-autonomous internet devices and eventually, the development of Artificial Intelligence. The thematic implication of this is that the future is completely unknowable, and it helps us to speculate as creatively as possible. After all, he was correct about certain elements of the future, especially the interconnectedness of the internet.
