ants came to our picnic.

There is no question here.

Are you trying to ask if this is a correct sentence? If that is your question, than yes, it is a correct sentence. Only you need capitalization.

I'm sorry to hear that ants came to your picnic. Ants are attracted to food, especially sugary or greasy foods, which is likely why they showed up at your picnic. If you want to prevent ants from ruining your next picnic, here are a few tips:

1. Food storage: Make sure all food items are stored in sealed containers or ziplock bags. This will not only help prevent ants from detecting the food but will also keep it fresh.
2. Clean area: Before setting up your picnic, inspect the picnic area for any remnants of food or sticky substances. Wipe down picnic tables, remove food scraps, and clean up any spills that may have occurred.
3. Avoid placing food directly on the ground: Ants can quickly find their way to food items placed directly on the ground. Use elevated tables, picnic blankets, or a clean tarp to keep your food off the ground.
4. Use ant repellents: There are several natural ant repellents you can use to deter ants. For example, scattering cinnamon, lemon peels, or vinegar around your picnic area can help repel ants.
5. Stay away from fragrances: Avoid wearing strong perfumes or using scented lotions as ants can be attracted to the fragrances.

By following these preventative measures, you should be able to enjoy your picnic without any unwanted ant guests.