Thankfully, Blogger has added protection in the form of word verification. Hopefully that will greatly reduce this problem. Word verification is very easy to activate. In the settings pane of the Blogger Dashboard, go to the Comments section. Scroll down to the option that reads
Show word verification for comments?Toggle the feature on, and there you have it. I thought I'd need to go to a fancier blogging tool to get this feature. It seems Blogger added it just in time for me, and no doubt countless others being plagued by bots.