@Sillver
Assuming you are making a reference to hunter x hunter, then not really...
at the end of the day, they are just anthropomorphic ants.
Sure they are somewhat humanoid looking, but what made chimaera ants scary was the fact they became what they did from eating and assimilating other creatures strengths.
They were actual chimaeras and not just human-looking ants.
These ants could have similar abilities, but there is nothing that suggests they do as of now.
@marcyvq
They explained it in this chapter.
They wanted the food and supplies that the city had as they were starving and lacked basic necessities, they are refugees after all.
The reason they attacked was that they had no items of value to trade for, and did not expect to be given food and shelter for free.
Honestly, they should have asked in the first place.
They lose very little from doing so even if the chance are slim that the town folk would agree.
They weren't using the surprise factor to attack, and without food, they wouldn't be able to actually siege the town anyway.
It just shows how bad the alrunes / elves leader is... but you can forgive her to some extent for not doing a good job considering she is stressed and desperate from being raided.