How to tell if a mantis is about to lay an ooth?

[Shadow]

How

 

[Sticky]

They refuse food. They are more defensive. Ive noticed my girls tend to hang upside down with an feeling of concentration about them. Maybe I only notice the last because I know my girls as well as I do.

 

[Extrememantid]

I noticed my females sit in a particular spot and move their abdomen up and down quite a bit. Just wondering, why does it matter? Like they usually do it when your not even around.. They seem to hold back when you are watching or disturbing them