https://youtu.be/9CCGXgSMx6g
This last Christmas, I was called out to seven ant issues. All resulted in the discovery of Pharaoh ants in the households. Why are these pesky ants coming out at this time of year? Pharaoh ants can take advantage of artificial heating in buildings to survive the winter. Once the weather became so cold, the furnaces were cranked up for most of the Christmas holidays and this really got the ants rolling. Infestations commonly occur where food is present, yet all interior walls can have many nests. These ants like to nest in well-protected and hidden areas throughout your house. Pharaoh ants begin new colonies by budding and with upwards of 20 queens per nest the extra queens are always willing to set-up new colonies. A colony of pharaoh ants will scatter if they detect danger i.e. sprayed with any toxic substance, creating multiple problems where there had been only one. This means that a small group of workers and a single queen migrate from their colony: up, down and along interior walls to start a new colony. Retail ant formulas rarely work and in fact if you think you have Pharaoh ants don’t spray anything at them as your walls will be crawling in ants in weeks. To try and identify these ants, they have light yellow bodies with red and black markings on the abdomen and are very small—about 2 mm long.
http://www.delta-optimist.com/opinion/blogs/deltabc-1.983313/blog-christmas-pharaoh-ants-1.2144391