Cave Cricket, Anyone?

24 Nov

Things have been a bit quiet here at Wild in Japan.  I don’t know whether to blame it on my busy schedule (I seem to be out of sync and then find myself rushing), the weather (we’ve had our share of miserable grey days, and a day of single digit maximum temperatures), the shortness of daylight (the winter solstice is not here yet, but it’s dark by 5:00 in the afternoon), lack of photo opportunities (everything either hibernation, dying or just not cooperating – I saw some chocolate vine, but that would mean sticking my mobile phone into someone’s yard, and then probably involve talks with the local constabulary…), or lack of motivation and general laziness on my part.  I vote for the latter, with the excuse that all the other factors contribute to it.

It’s still a bit early to write about the solstice, or a quasi-Christmas theme like false holly.  I was about to do another ideogram post, but coming home a couple of evenings ago, everything changed…

I spy a long-legged shape in one corner of the entrance hall.  I immediately recognise it as a camel cricket or cave cricket (Diestrammena apicalis or Diestrammena japonica), a distant relative of the giant weta, the largest insect on Earth.  I got a couple of photos back in an earlier post, but this one came to me.  And this time I had an insect cage and camera…

The cave cricket with a ¥500 coin for scale.

This cave cricket is known as kamadouma (竈馬), literally “hearth horse” due to where humans often encountered it and its appearance – the head, when viewed on, does look like a horse’s head.  Other vernacular names are okamakorogi and benjokorogi.  The word korogi (蟋蟀, 蛩 or蛬) means “cricket” – it does bear resemblance to its relative, the true crickets.  “Okama” can mean hearth (a variation of “kamado”), but can also mean “kiln” or “cauldron” – the latter being used in conjunction with the hearth.  “Benjo” is a name for toilets, particularly the old long-drop variety.  Again, the names reflect where people encountered the insects – dark, damp places.

An old-fashioned kamado, with kama on top. No, my kitchen does not have these.

Typically, however, these insects would be found in and under rotting logs, in tree hollows, caves and rock crags.

You can see the resemblance to a horse’s head in this shot.

Males typically have a larger body than females, although a female’s overall length is usually longer due to the ovipositor.  Unlike crickets, they lack wings, but have well-developed legs and are powerful jumpers – apparently, captive specimens have been known to kill themselves when jumping in a confined space.  Also, the absence of wings means they are unable to sing in the manner of grasshoppers and crickets.

This photo gives some idea of the tail-end.

They are well adapted to living in dark places.  Their eyesight is quite poor, but their sensitive antennae are much longer than the rest of the body, something like three times the body length.  Lacking any defensive abilities such as biting or stinging, the cave cricket will attempt to flee from predators, often by jumping toward the perceived threat in the hope of startling it.

You can see the length of the antennae and the legs in this photo.

Their main enemies are spiders, geckos, birds, frogs and wasps.

Cave crickets are omnivores.  In captivity they will eat almost anything a human will.  In the wild, they feed mostly on plant material, but will consume other insects or even dead animals.  Cannibalism can be rife in high-density populations.

I plan keeping this one for a few days.

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2 Responses to “Cave Cricket, Anyone?”

  1. ominousdistance Friday, March 1, 2013 at 9:51 am #

    I remember these, from Nagano-ken and Gunma-ken. Not surprisingly, both residences I was visiting were in more or less deep forest. Definitely the most intimidating looking insects I’ve ever seen, never seen anything like it on the US West Coast, although I guess they exist here in the US too, thankfully more on the East Coast I believe.

    • wildinjapan Saturday, March 2, 2013 at 7:22 am #

      I heard that they have found their way to the US, where exterminators have been employed to deal with them.
      If you want a truly intimidating insect, however, you should take a look at the Japanese hornet!

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