Down Services Not Creating Alerts?

I just installed the trial edition of OpManager on a small network with 4 Linux servers and 2 windows servers. I created an Email and SMS alert profile, applied it to all servers. I also added a couple of URL monitors and these seem to work and send an email when the site is down. However, if I take down a service on a server (mysql for instance), it will show up as being down in the OpManager interface, but it does not show up as a Down Service on the OpManager Home Page Summary, nor is an alert sent out?

Is it necessary to create thresholds for each and every service in order for it to generate an alarm when the service is down?