I'm seeing a few ideas about evolution that are a bit backwards. Parthenogenesis is a serious mechanical step in a species that rarely occurs because of a lack of population in a species. A species does not simply develop this sort of thing out of a need for it. Evolution does NOT happen from NEED. It happens through natural selection which is nature favoring one characteristic because that characteristic helps whatever the living thing is (+viruses) survive. The characteristics are there first and the ones that have them survive and reproduce while the ones without them don't.
The females that already can clone themselves are the ones that survive and continue the species. This 'ability' is more of a mutation in some gene they have to reproduce with and I'm sure the first to be able to do this would also be able to reproduce normally with a male.
If you want to make your own line of parthenogenesis capable mantids you might want to reconsider because it would take MANY females not being mated so you could wait for the one who has this trait.... I'm talking millions... but at the same time you would have to keep making more females to repeat the process till you find the one with both traits. AND odds are that the one ooth you find to hatch without fertilizing it will have SO weak mantids that they don't even survive at all. You see, that female which the ooth came from (the female with both traits) would need to be mated over and over again to produce a line that has her genes. you would wait until finally (and randomly) one of her descendants kept and strengthened the trait enough to clone herself perfectly but how would you know unless you didn't breed her with a male and thus lose the trait and have to start all over again because the mantids weren't strong enough.... one of those catch 22s
the only way I can think of to do this synthetically: you would have to examine the DNA of every female mantis to find if they have the trait or not (finding traits in DNA is something we can hardly do in humans), clone the female which does MANY times(not an expert on cloning but never heard of insect cloning), breed all the clones but keep one unmated to study the offspring she produces without a male, analyze all the female offspring every clone produces to make sure they still have the trait because half the chromosomes come from the male, half from the female, clone all the ones that still do, rinse and repeat until you get a female which can produce offspring which can make it to adulthood to continue the line and HOPE their offspring are just as strong
Yep, sorry 'bout the rant, but a lack of males would have nothing to do with the females evolving