Ants shouldn't be too much of a problem.
The danger is that they could be moving pests from plant to plant. But otherwise I wouldn't worry too much about them.
I had a big Nepenthes collection at one time.
How to grow them - similar to intermediate orchids. High humidity, free draining bark based soil. Min temp of about 12*C. Regular waterings with "soft" (ie low in calcium carbonate) water. A bit of shading.