It has happened a couple of times with the black widow spider that I have captured it in the net, seen the white light go up that indicates a capture, and then nothing. Is this supposed to happen?

I have successfully caught the spider once and have it in my museum. Most of the time it disappears before my mayor even arrives with the net, but to disappear after capture seems to be worthy of Houdini.

It was about to disappear when you captured it. It stands still and flashes before it disappears, or disappears while walking into a tree or rock or something.
It's happened to me, but it's really frustrating when it's a black widow or a tarantula!

Thanks for the input. Yes, I've seen that happen. It's not the flashing on and off I mean. But in these cases there's the white lights that sparkle upwards and the twinkling sound. But the only thing missing is the secretary saying, "Woohoo! You've captured a black widow." And of course, it doesn't appear in the inventory. Does this happen to you too?

I've never had it happen with any bug other than the black widow. Sometimes the net goes down and the bug disappears without the sparkles, so I know that's a miss. But I thought the sparkles meant you had it. Yes, it's frustrating to have it disappear at that point. So much so, that I will probably not bother trying to capture them again now that I have one in the museum unless it appears on my mayor's foot.