Blue Gender, Terra Formars Recommendations
Both are sci-fi horror anime dealing with humanity fighting insects much like the film "Starship Troopers". In my opinion, Blue Gender is the more atmospheric of the two while Terra Formars has more action.
Both series revolve around the life-and-death struggle to survive against an insectoid aggressor. Blue Gender protagonists are heavily armored and munitioned humans, up against giant insects. Terra Formars' characters are genetically augmented humans, battling uniquely evolved, intelligent, and scarily logical bipedal insects. Politics, questions of morality and humanity, and identity are interpreted themes.
These two anime focus on humans trying to save the world from evil powerful bug monsters. Both of these anime have a special elite troops that faces these evil creatures from destroying humanity. Not to mention these two shows are filled with action, violence, blood and gore.