ANTS
Varieties of ants commonly found in and around homes are the Argentine and Thief Ant. They are attracted to sweets and other foods. They travel in trails and nest under and around buildings. It is very common for ants to work their way up from under a concrete foundation on which a house sits on, to eventually be found in cupboards and on counter-tops. Ants likely will try to come inside buildings  when the weather starts to get too hot, cold or wet.

FLEAS
The most common is the Cat Flea.
It is commonly found on dogs and humans when the preferred host is not available. While the adult flea can live several months without food, the female must have a blood meal before she will produce eggs.