Ant chemistry
Formic acid produced by ants plus a tree resin, creates an antifungal/antibiotic compound for the ant colony. This was one of my favorite science news stories this year.
The rest of the list from Science is here:
http://www.sciencemag.org/news/2017/12/our-favorite-science-news-stories-2017
http://www.sciencemag.org/news/2017/03/chemist-ants-brew-antibiotic-cocktail-protect-their-colony