So, Von Neumann probe from the galaxy Andromeda is invading the Milky Way, and most species are getting their asses handed to them. A few planets have already come under the invaders control, and the United Terran Federation and Qualian Star Empire have teamed up to try and stop them from coming any closer to the inner galaxy. The great Qualian imperial armada and the entire UTF navy has set up blockades around the controlled planets, and have stationed men on planetary based. Which brings up a question. What advantages would a reptilian species like the Qualihas have over humans in battle?
There is little defence against von neumann probes.
A von neumann probe is most likely a machine - able to replicate itself when arriving at a star system to then replicate itself further, to pass on to other neighbouring star systems.
Multiplication is the key here - as once von neumann probes start producing themselves - it's very hard to stop them. Much like weeding grass, eliminating the exposed grass is only a small part of a much larger root system well established long before you started weeding.
Faced against such an adversary it would be difficult to think of a defence - other than that of finding a weakness to which they are susceptible (and since they are replicas, potentially a universal one) or creating probes of your own to battle them.
It matters little in the cosmic scale whether you're reptilian or mammalian, as most matters had already likely been decided before you were engaged.
Reptiles would do well against humans in a siege
Failing a military outcome, sieges can often be decided by starvation, thirst, or disease, which can afflict either the attacker or defender. This form of siege, though, can take many months or even years, depending upon the size of the stores of food the fortified position holds.
Reptiles would do well against humans in this sort of endurance contest. Reptiles can power down their metabolisms in a way unavailable to mammals. They require less calories and less water, and maybe less fuel for heating if they are ok with torpor. The army laying siege often suffers disease and shortages comparable to that in the city -= in his Apologie Ambroise Pare describes leaving the city he had been in after the besiegers left, and finding starving, dying men who had been abandoned by the besiegers as they left in disarray. On the inside or the outside of a siege, reptiles have an advantage.