It can also encourage other Solitary Bees and Wasps that can be of great benefit to the home gardener...
There are two species of tube-nesting solitary wasps which may also be attracted to your Solitary Bee House.One is the native small mason wasp Pison morosum, which makes cells of mud within which it stores spiders, and the other is the immigrant eumenid wasp Ancistrocerus gazella, this one may bring with it benefits, especially for gardeners! It also makes cells of mud, but which stores leafroller caterpillars.They are safe and interesting to observe!

An organic alternative to reduce leaf roller, numbers!
DID YOU KNOW There are three common pest species of leaf roller in New Zealand. The brown headed leafroller, the light brown apple moth and the greenheaded leaf roller. They are major garden pests.