January 14, 2010

Making houses for New Zealand native Weta

By Dr Clive Dalton

An ancient animal
The New Zealand Weta is a very ancient animal - they were around in the time of the dinosaurs when New Zealand was still joined to Australia dating back over 190 million years.

There are over 20,000 species worldwide with over 100 species in New Zealand with other relatives in South Africa as well as Australia. Weta are often called 'King Crickets' in the rest of the world.

Simple life cycle
Weta are insects (with six legs). They have big back legs for jumping and good strong jaws like secateurs for chewing. This group of insects (Orthoptera) also covers grasshoppers, crickets with a very simple lifestyle where the adult lays eggs which hatch into nymphs, which then grow into adults again.

Weta have shiny brown bodies and no wings. Their 'feelers' (antennae) are often as long as their body and their back legs often have spikes that they bring forward to defend themselves. Females have a long spike at the back which is for laying eggs and is not a sting.

Weta are generally vegetarians though some species in New Zealand eat smaller insects. They are also nocturnal and during the day love to live in holes in timber such as trees or fence posts. This is the secret to observing them using a Weta house (see below).

Main New Zealand species
Work is still going on identifying and classifying the many New Zealand Weta and their biology. Here are some of the main ones:
  • Giant Weta (Maori Weta Punga). Deinacrida heteracantha
  • Tusked Weta. Motuweta isolata. There are two species currently.
  • Tree Weta (Maori Putangatanga). Hemideina thoracica is the Auckland Tree Weta of which there are 7 species currently. H crassidens is the Wellington Tree Weta.
  • Ground Weta. Hemiandrus species. This Weta is less related to the above species, all of which have a lot in common.
Further information & acknowledgements
Check Massey University website, for the work of Mary Morgan-Richards, Steve Trewick and other researchers. Special thanks to Priscilla McAllum for help and information.


Making a Weta house.


Happy weta sharing a compartment in weta box

To the Weta, this model of house provides a nice dry and dark hole in a piece of wood to rest during the day. To the human observer, the swinging door allows the Weta to be seen (admittedly folded up), during the day without the Weta escaping. This is providing you block the entrance hole before opening the door. If required, the Weta can be removed by unscrewing the window.

If you want to keep the Weta in the house during transport, you'll need a wooden plug for the hole as they will easily chew through softer materials including plastic. They'll even chew through wood too if determined to escape.

This model house described can be scaled up in size with many cavities and entrance holes.

Building stages
1. Start off with timber with a natural preservative. 'Treated timber' is not suitable and will kill the insects. In New Zealand a good source of wood is old Totora fence posts or fence battens. Cupressus Macrocarpa is also good with natural preservatives.

Section of Totora fence batten 250mm long

2. Cut a thin slice (10 mm thick) off one side for the door.


3. Mark the end so the door will fit neatly when assembled. It doesn't matter if your cut is not straight as long as you don't confuse the ends.



4. Cut a piece of perspex (any thickness will do) about 40mm wide for the window and draw around it to mark the position to router out a recess for it. Put the window towards the bottom to give plenty of room at the top to attach the door, and allow plenty or room for inspecting the house residents when the door is opened.


5. Router out the recess for the window.



6. Make the window a good fit into the recess.



7. Use a 25mm Forstner bit to drill holes along the length of the recess, leaving room at top and bottom to scew the perspex down. Depth of holes should be about 30mm.



8. Take the sharp edges of the sides of the cavity with a chisel.



9. Bore a 20mm entrance hole in the side of the house to go through into the central cavity.




10. Use a countersunk 10mm screw in each corner of the window to fix it firmly in place.




11. Make a hook from Number 8 wire, stapled on the back to suspend the house in position.



12. Use a 25-30mm screw to fix the door.



13. The finished Weta house with swinging door.









5 comments:

  1. Very cool!

    We found a Weta in the kitchen just before Christmas. I took her to work... she seemed the perfect specimen and seems she was. She is now helping many Auckland children see what a Weta looks like close up :-) Don't look if you are squeamish! http://www.flickr.com/photos/porkynz/sets/72157623095473189/

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  2. we have one living in the wall cavity of our bedroom, didnt mind at first but it is now keeping me awake at night making loud noises, the cat was playing with one within inches of the hole we think it is using, we caught it and released it into the native woods at the back of our house, but 2 days later the noises were back, there are also large droppings near the hole and today i find some of the wall insulation as be pushed out, how can we get rid of this and keep it from coming back without killing it..

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  3. From Weta expert Dr Prescilla Wehi, Institute of Natural Resources, Massey University, Private Bag 11-222, Palmerston North, New Zeland.

    Hmm. Tricky one. Maybe entice them out with carrot and capture again? I wonder whether there is more than one weta there (or a different one), as it is hard to imagine they would try and find their way back from a long distance. We have a group meeting today so I will ask everyone for suggestions and get back to you!
    Cilla

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  4. Ok, here is a slightly better idea:

    You could entice it/them out with a bit of food (dead moths as well as carrot could also be popular), mark the weta (use a bit of nail polish on the back leg, or just behind the head), remove the weta to a distance away and then at least you will know whether it is the same one coming back or a different one. I would also definitely block up the hole. There should be plenty of roosts in the bush for them so don’t feel guilty about denying them a convenient place to live.

    Love to hear how you go with this.
    Priscilla Wehi

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  5. the carrot worked a treat, placed it there just after sunset, it came out within 10 mins, thanks very much, going to seal the hole up now and hopefully we wont have any more house guests..

    =))

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