It looks to me like the size difference between europeans I collected in aug compared to september somewhat is the cause of mating failure. It seems like the different lengths makes it hard for the mating to work out.
But, ya, sometimes he can sit there for 12 or more hours before he gets properly started. Then again, sometimes he may never get started.
Mrs Manda are you 100% sure that you have a male...8 abdominal segments, long antennae, and smaller head. As for the question of her already being big and already mated, I mate my Religiosa mulitple times. Especially when my girls are big, days away from laying an ooth and busting at the seams. I mate them again 3-4 days after laying their Ooth just to ensure complete fertilization. The reason I ask if you are 100% sure is because I made the mistake of putting a skinny little female in with one of my larger females....Gee I wonder why they are not mating? Duh! So it happens.
Getting a new male ready:
Males, especially freshly caught males are skittish, especially if they are agitated from being handled or feel threatened. They need at least 72 hours after being caught to settle down. Do not attempt to mate him until he has eaten a couple of flies and been watered for a couple of days. Freshly caught males might be freaked out and not eat for a day or two, don't worry, just stick a house fly or two in with him, eventually he will eat. Boil some water on a low simmer for 20 minutes to remove any chlorine, let it cool to room temperature and place it in clean (never had soap or chemicals in it) spray bottle. Give him a couple of days to settle down and make sure to take him out everyday for at least 30 minutes in a small room with a house plant and let him fly around (cover vents). Males need a lot of water spray down the plant so the leaves are covered in water droplets, place him on it, then lightly spray above him. He will either place his head down and drink from the water droplets directly off the leaves or preen himself collecting water from his coxae (front legs). You may also notice he will raise his coxae up in the air to collect the sprayed water as it falls. Be patient, sometimes they don't immediately drink. A calm well-adjusted, fed, and watered adult male will spring into action when given the chance.
Mating Area:
How big is the area for mating ie. a shoebox size housing, a laundry sized box, an open room? I use an 18 gallon Roughneck tote and put a deer antler in the middle. The female needs something to walk up and perch on something to cling onto in a downward position. If you are sticking the male into the females housing, especially a male that you just caught it maybe too freaked out to give the effort 100%.
If you have a laundry sized box, use it and gently place your male inside. If he tries to fly out or freaks out, just wait until he perches and calms down. Then place your already fed female about 6 inches in front of him, preferably facing in the opposite direction. Her movements will immediately draw his attention, he will approach timidly, after a couple of minutes he will get closer, then with a short (flying) hop he mount the female, most time backwards, no worries he will figure it out and right himself. Mating generally takes about 4-5 hours. Your female if well fed will be more than hospitable, will not kill your male, and will remain like statue during and after the mating.
About an hour after mating take you male out of his housing and give him a 30 minute water break. As well make sure there is a feeder in with the female when you place her back into her housing....mating makes them hungry.
Different sizes between sexes:
My experience so far is it makes no difference, small female large male, large male small female, if all other conditions are correct they will mate and the male will easily survive the ordeal. I think the biggest thing is for both to be well-fed, hydrated, calm, and in an environment suited for mating.
All of my Religiosas are wild, I have never lost a male and I have never had an unsuccessful mating...except for trying to mate 2 females...yeah..that didn't work.
