Your article got my attention and I certainly appreciate more information than I had before.
When I moved up here 4 years ago, although I've found many kinds of spiders and other creatures, of which I have little fear, the Black Widow was not evident on my 5 acres.
A year ago, my son's GF moved up here from 2 zones south. Among other things, she brought the Black Widow's with her. The Widow's spent the summer and fall making nests and leaving egg sacks about. One was camped out by the hose bib inside my pumphouse. My fears led me to the ether can. But I know there were more out there and in my porch greenhouse.
I went everywhere I could think of to clean out the nests and eggs from those places they lurk, hoping they would not return in the spring. During the winter we had an accidental kerosene smoke cloud in the GH and I suspect this might have taken care of any stragglers.
I guess what I want to know is, will these creatures naturalize in a new environment easily or is there a chance I have seen the last of them?
I have learned over these years to co-habitate with the creatures that belong here and with the exception of an occasional scorpion sting, have been pretty successful with this.
they are very good at invading gardens, but I don't know as much about them in that climate where you live.. in arid climates, they are ubiquitous and impossible to completely get rid of... still, they seem to do very little harm