Preying Mantis - to kill or not to kill

"Tiffany is a bad-ass. She noticed a preying mantis and tore its head off."

We were gathering seeds for restoration at a Nature Preserve. One of us had conferred for a while with Tiffany, the site's Director of Land Management, and returned to our seeds group with the unexpected report. 

The large preying mantises that we often see are from China. We could call them an "invasive" or possibly a "naturalized" species. Tiffany (name changed to protect the possibly innocent) was reducing numbers of this predator to help conserve rare invertebrates in this preserve.

I've watched them for years - with awe, appreciation, and a bit of unease. I've seen them in preserves and especially common in my yard, which is devoted to raising rare seed for ecological restoration. Of course, the dense rare flowers attract pollinators, which seem to attract mantises. 

This photo includes at least seven monarch wings. Above them was a preying mantis, busily hunting for more from its perch on a rare wildflower. 

From time to time I had noticed suspicious monarch wings in the grass. And mantises on the flowers. My practice had been to respectfully maneuver the mantis onto a stick and transfer it to some other plant.

But today, I thought about Tiffany. 

Monarch butterfly on the (formerly) Threatened plant species, savanna blazing star

This time of year, monarchs especially flock to our savanna blazing stars (Liatris scariosa), a Threatened species in Illinois, at least until efforts like ours raised its status to the inspiring category: "formerly Threatened." Sometimes ten or a dozen monarchs mob the plants at once. 

Increasingly, these same plants attract mantises, like the two below, busily reproducing their kind:

It would seem rude or worse to interrupt, don't you think? 

And yet, below is the one I saw today ...

... the one above the scattered monarch wings, at a time when I was still considering the example set by Tiffany.

J.R.R. Tolkien wrote: 

"Many that live deserve death. And some that die deserve life. Can you give it to them? Then do not be too eager to deal out death in judgement."  

I have to admit that I consider mantises to be miracles of evolution and deserving of respect and kindness. At least sometimes. As a steward, I kill buckthorn and sometimes even maple, to restore a rare oak savanna habitat. All trees deserve some level of respect, but, after thinking twice about it, we kill some to save other (threatened) life.

I'll also admit that my emotional and ethical self thinks - not just twice - but three or four times about killing animals. Yet I do squash mosquitoes and cockroaches. Conservation land managers "cull" or kill overpopulated deer, which is an important thing to do in the absence of other predators. 

In my yard yesterday, inspired or corrupted by Tiffany, I tried to pull off the head of the above mantis. Instead, it's body broke in two at the waist, which all the same had the same effect. As below: 

Or to show half of its remains even more starkly:

It meant no harm. Predators are not an evil. They are much-needed regulators that keep other species from malignant over-population. 

But how about alien or malignant predators? Do some of them deserve extreme prejudice? Gardeners and farmers sometimes buy and distribute mantises as non-chemical insect control. It makes sense to develop methods of pest control that don't depend on dangerous chemicals. 

Do agencies have protocols or policies on this kind of thing? I felt I could get away with being the predator on this one in my yard, especially considering the circumstances. But what about in the forest preserve where I'm a steward? I asked one person who said, absolutely not: No volunteer is authorized to kill any animal. But, I wondered, what about wood ticks and deer ticks? I kill them when I find them. My friend Sai Ramakrishna found one that had travelled home with him and brought it back to the preserve, not wanting to abandon it in some possibly lethal habitat. He respects their lives in ways that I apparently don't. Perhaps some people could help develop improved ethical principles to help balance out the goods and evils here? 

As with many questions, we may be in the early stages of figuring this one out. 

Kristen Frentzel of the Brandywine Conservancy thoughtfully recommends trashing Chinese mantis egg masses here. She states that the big Chinese mantises have diminished numbers of the smaller, native Carolina mantis. The egg masses of the two species are easy to tell apart. I've only ever seen one Carolina mantis egg mass, despite seeing at least hundreds of Chinese mantis egg masses. Of course, I haven't looked seriously. 

Perhaps the Carolina mantis played an important role in our ecosystems - and perhaps the Chinese mantis plays a destabilizing one? Or perhaps like the European earthworm and fragmentation it's just a fact of life?  

It sure would be interesting if someone were to study the overall impacts of reducing Chinese mantis populations, although it would be insanely difficult.