Last September, my colleague Kevin Murphy and I spent hours finding and watching dozens of Chinese Praying Mantises in the fields of Eliza Howell Park. They were nearing the end of their season — and their lives — and their last couple of weeks include mating and egg laying. The only survivors for the following year are the eggs encased and attached to plants judged sturdy enough to remain standing through the winter.
Since September, we have checked occasionally on a number of these egg cases (oothecae) and were pleased to see that they appeared to remain intact.
During the Fall and Winter and early Spring, the eggs hatch and the young grow inside the egg cases into very small versions of the adult, but without wings. We have been waiting to see them emerge, not knowing exactly when this would happen or whether we would actually be able to observe it, since they disperse quickly.
On May 17, Kevin spotted one hanging from an egg case.
We expected to see them energe in large numbers, not one at a time. Was this one the first to emerge from the case or the one remaining after all the others had hurried away to get started on their unencased lives?
On May 21, I came by at the right time and found an egg case open with many departing mantises. As I watched, they quickly climbed to a branch to get away. (Emerging mantises are hungry and have been known to eat other egg case graduates.)
Eight months is a long time inside, when the total time from egg being laid to death is only 12 months.
Over the summer, the mantises will slowly grow until they reach full adult size. Then, in September, they will seek others out to prepare for another year, another generation.
We will be there, to observe the cycle continue and to try to gain additional knowledge and understanding of these fascinating insects.