That could be the answer Keith. I left about 4 acres grow,well actually not. Last time I had a high like this i kept all mowed. I had ampalaya (bitter melon) growing that yr. I was assuming it was because of preferences of what was growing here. No idea
If you wait to mow, until after it warms up in the Spring, about 150 to 180 baby mantises will hatch out of each case. If well fed, female mantises can lay multiple cases. It does not take many years to have huge numbers of mantises.
If an egg case gets knocked down, water gets up the holes in the underside and kills the eggs.
Keith