Fatal attraction

Walking home along Mortimer Terrace a few days ago, I stopped to watch a praying mantis crossing the sidewalk.  Its halting gait on the concrete made it look especially vulnerable to a bird attack or human footstep, so I let it crawl onto a stick and moved it to the grass.  I recognized the species immediately, since I found the same type a few weeks ago farther north in Papamoa.  I submitted the photo to NatureWatch NZ, where it was identified as a South African praying mantis (Miomantis caffra). Just like the one in Papamoa, this was a female whose abdomen was swollen with eggs, curbing her normal agility.  The species is also known as the “springbok” mantis after their ability to jump like an antelope.

SA praying mantis Papamoa

NatureWatch NZ has many great tools on its site, including species descriptions and  maps of where they have been found. As indicated by its name, this praying mantis was brought to New Zealand from South Africa, though it is unknown how or why. A schoolboy near Auckland found a few immature ones in 1978, but it took biologists several years of raising them to adulthood before they could determine that they were in fact a common South African species. Over the years, this initial population has spread across New Zealand, though there are still many gaps on the Nature Watch NZ map for this species.  Wellington was one of those gaps – until today.

map

When we find a praying mantis at school in the US, I’ve had students solemnly inform me that a person will go to jail if they kill it.  There seems to be a widespread belief that 1) all praying mantises are the same species, and 2) they are legally protected.

Neither is true.  In the US, we have about 20 species.  Several of the introduced species, such as the Chinese praying mantis (Tenodera sinensis), are more commonly seen than our native mantises. They have a reputation as a beneficial garden insect because they are predators, but they are just as likely to eat other beneficial creatures as they are pests, including each other.

After I posted the first photo of the praying mantis in Papamoa to NatureWatchNZ,  it was duly identified and recorded on the map. With my second photo, I received an additional caution from one of the site experts: “This is the first time I have heard of it in Wellington. Several records from northern South Island and I photographed it in Palmerston north the other day. My advice is kill it whenever you see it because it is rapidly replacing the New Zealand praying mantis.JR

So much for my goodwill gesture of moving the pregnant female to a safer location. This “displacement” of the native New Zealand praying mantis (Orthodera novaezealandiae) is due to differing mating protocols between the two species, well described in this Science News article. Essentially, the New Zealand males (who are accustomed to not being eaten after mating) are hopelessly attracted to the South African females…who always eat them.

I’m left with the fervent hope that I don’t find any more South African praying mantises – for everyone’s sake.

 

 

 

 

 

 

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