Mantispids, mantis-flies and misnomers

You can be lucky sometimes! I had read about the insects commonly called “mantis-flies” and seen many images of them, but I had never seen a live one in the flesh. We were at dinner with neighbours one night when one landed by my plate of food – no kidding. Pandemonium ensued as I tried to catch it, shouting for a container of some kind. Finally it was corralled and I had one to photograph. Here it is! (below)

mantis-flyBut what is a “mantis-fly”? Is it a mantis or a fly? Neither actually. It’s a type of lacewing and is therefore a member of the order Neuroptera. Mantis-flies are members of the family Mantispidae within that order. They may be known by several other common names like mantidflies, mantispids or mantid lacewings. Confused? Which is the correct term? I would plug for “mantispids” because this reflects their family name.

We have about 45 species of mantispids in Australia. Adult mantispids have distinctive mantid-like raptorial forelegs and two pairs of lacy wings. Adults of some species are up to 25mm in length, although the one pictured is half that length. Another distinctive feature of mantispids is how the first segment of the thorax (the pronotum) is very elongated, appearing like a long ‘neck’.

mantispid

Adult mantis-flies are predators of small insects such as flies, using their raptorial forelegs to catch prey. The larvae of the mantispids which occur in Australia are parasites of spiders! Here’s how it works. Female mantispids lay large batches of small stalked eggs, often hundreds at a time. Hatching larvae either search for a spider egg sac and burrow in, or climb aboard a female spider and enter the egg sac as it is constructed, to feed on the spider eggs. Larvae that climb aboard female spiders may feed on spider blood while waiting for the egg sac to be produced. If the larva boards an immature spider it can put its own development on hold (a process known as diapause) until the spider moults into a mature female.

There are three larval instars in mantispid life cycles. The second and third instars are quite sedentary compared to the mobile first instar larva. Pupation occurs within the spider egg sac once all spider eggs are consumed. Emerging adults vary considerably in size depending on the number of spider eggs eaten as larvae. Some mantispid species go through an elaborate courtship prior to mating which includes sparring with their raptorial forelegs. Some common species may be drawn to lights at night, while others may be seen ambushing prey on flowers.

mantid lacewing

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10 Replies to “Mantispids, mantis-flies and misnomers”

  1. Thats incredible! Especially about the larvae! Who knew! And by the way, your reaction at dinner is EXACTLY how things go at my house when I find something. So funny.

  2. I’m with Lisa Donovan – excitement over the bug find is extreme in my household. I spotted a bee hawk moth adult perched on a tree the other day and went into caniptions. No camera handy 🙁
    Have managed to successfully rear the odd one or two, but exciting to spot one buzzing around. Feeling you joy with this mantispid.

  3. In 2006, I found an egg-case behind the curtain in my office in Kabul. Not knowing what it was, I left it on my desk for some weeks. Suddenly thousands of tiny green mantis appeared and moved on to the window pane where they proceeded to eat one another.
    I have an amateur photo, but don’t know how to add it to this comment.
    A very interesting article.

  4. Fantastic photos indeed. Well done. Loved the article. I’m from Canada enjoying the minus 25 degree weather…lol…. waiting for the hot weather to return…since you stole it from us !! It would be interesting to find out what similar insects we share. I own a property maintenance and landscape design & construction company . As I plant gardens I want to attract the good insects to my gardens and keep the invaders out that cause destruction in my gardens… no small feat I’m sure…

    • Thanks Shane. I am sure there will be similarities even though we are at opposite ends of the planet!