The Small White is a strong flyer and the U.K. population is usually increased by immigration of other Small Whites from across Europe.
   Adults can fly many kilometers as individuals. Some have been seen flying as much as 12 km in one flight.
   Females fly about 0.7 km per day and move 0.45 km from where they started.
   Males are on patrol all day around host plants to find females to mate with.
   When the male  sees a female, it flies erratically up, down, below around her until she finally lands. 
The male then flutters, catches her closed forewings with his legs, and spreads his wings. 
This forces her to lean over.
   He then flies a short distance carrying her suspended beneath him. 
   If she is unreceptive, she will fly vertically, spread her wings and raise her abdomen to reject him.
   Females will readily lay eggs on both cultivated and wild members of the cabbage family.
   Birds are a major predator in U.K. town and city environments (such as in gardens), while arthropods are much more of a threat in rural areas.
   Caterpillars exist on the undersides of host plants, and they are colored a green that will help them be less noticeable to predators.