I found it was very hit and miss. One day I left my plant outside for 4 hours and it caught nothing. 1 day later it was outside less than 1.5 hours and caught 3 bugs. They have also caught several bugs that were inside my house so don't rule that out
. Now I manually feed them freeze dried blood worms a few times and then I catch an ant outside and feed the ant to an appropriate sized trap.
I use an old, clean and empty salsa jar, put ant inside and put in my freezer for 5-6 minutes. Check to make sure ant is lethargic but not dead, pick him up with tweezers and place in trap. 50% of the time, the trap closes immediately. If not, as the ant starts to stir it hits triggers and snap. Ant then strugglers and trap seals, dinner time. Yesterday my maroon monster achieved this feat in record time for me. From the time the trap closed until it was fully sealed and beginning digestion was about 15 minutes.
Warning!!! Feeding your plants this way is extremely awesome and addictive! Use at your own risk