Disappearing wasps

Discuss natural history subjects not strictly related to birds. Reports of interesting mammal, reptile, and invertebrate sightings are welcome.
john b
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Disappearing wasps

Postby john b » Mon May 02, 2016 12:15 pm

While paper wasps seen common on Little Barrier island both German and common wasps seem to be completely absent or at least very rare. I'm sure this was not the case 20 years ago and given the problem these pests are in the New Zealand bush I wonder if someone can work out why they have disappeared. I have heard anecdotally that they have also disappeared on some other pest free offshore islands. They undoubtedly do use rat holes to build their nests in but they will also nest in many other places. My money would be on Queen wasp predation in the spring by Saddleback or Kokako.
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Steps
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Re: Disappearing wasps

Postby Steps » Tue May 03, 2016 8:28 am

Sort of had a similar abstract thought over this last summer...
For at least the last 20yrs+ in our sth Auckland back yard we have had paper wasps... several little nests all over the place, espec around the grape vines... couple yrs ago had a huge one in the roof of the house a good meter in diameter and high from ceiling to roof...
This yr has been noticeable by their absence.
I had thought it maybe because now plant cali/ broccoli thru the winter to avoid the white butter fly caterpillars, on the other hand the monarch butterfly caterpillars , another source of attractant are still in great numbers.
I wonder if this is a 'island ' thing or maybe more general ????
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David Riddell
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Re: Disappearing wasps

Postby David Riddell » Wed May 04, 2016 8:25 am

Round here (rural Waikato, north of Hamilton), German wasps seem to be declining, while Asian paper wasps continue to increase. Not sure if the two trends are connected, or if the decline in German wasps has to do with the intensification of agricultural practices, or something else entirely. (We also get a few common wasps here, but nowhere near as many as the Germans, even in their reduced numbers.) When I was a kid in the 1960s there were big numbers in the summer months - it was quite standard to have two or three buzzing around on the inside of the dining room window, my mum was always squashing them. I also remember my dad talking about how embarrassed he was at all the wasps everywhere one time when he had overseas visitors, think that would have been the late 1950s. These days we sometimes get a reasonable number on the windfall apples under our two trees, though nothing like we used to get, and there were very few this year even there.

I realise many places around the country still have huge wasp numbers, particularly commons in the beech forests, and there's a patch of mixed broadleaf/podocarp/kauri/kanuka near here where a volunteer worker has been killing big numbers of German wasp nests, so I don't want to suggest this decline is general. Really interesting if it's true that German and common wasps are disappearing from predator-free islands. Must keep an eye on Maungatautari and see what happens there. John, you mention saddleback and kokako as possible wasp predators, what about kaka? Are there kaka on these other islands where wasps may have disappeared? Does anyone know how many wasps are there on Great Barrier, where kaka are still in fairly good numbers?
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Neil Fitzgerald
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Re: Disappearing wasps

Postby Neil Fitzgerald » Wed May 04, 2016 9:20 am

Could it be the mites?
http://www.radionz.co.nz/news/national/ ... inst-wasps

I still seem to have plenty of them (German wasps) this year near Pirongia. They kept eating my rhubarb plants. Last year they took the new shoots off a banksia hedge. I think I'm up to about 10 nests I've dealt to within 100m of the house over the past few months. I was seriously considering getting a vespex ticket. Bring on the mighty mite!
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David Riddell
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Re: Disappearing wasps

Postby David Riddell » Sun Jan 21, 2018 1:26 pm

john b wrote:While paper wasps seen common on Little Barrier island both German and common wasps seem to be completely absent or at least very rare. I'm sure this was not the case 20 years ago and given the problem these pests are in the New Zealand bush I wonder if someone can work out why they have disappeared. I have heard anecdotally that they have also disappeared on some other pest free offshore islands.

Just been looking through some articles on the Landcare Research site, and it seems someone is indeed starting to look at this issue. Will be interesting to see what she finds.
https://www.landcareresearch.co.nz/publ ... uraki-gulf
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Steps
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Re: Disappearing wasps

Postby Steps » Sun Jan 21, 2018 6:11 pm

We put 3 bee hives in the back yard, middle of the veggie garden, in the late summer last yr.
Wasps and bees are not a good mix, for the bees. So we experimented with a couple wasp traps.. sort of 1/2 worked.. but a concentrated fly swat around the hives couple times a day for a week certainly reduced the numbers.
Reduced the numbers enough that te bees where knocking them oyrt faster than we could... And the hive had grown from 1 box to 2 / 3 boxes high.
Come this yr, not a wasp to be seen.. in our yard or in the 9 neighbours yards
The only thing we can , and the bee guys, can put it down to is the bees are killing the wasps faster than they multiply... ie the wasps go out for food, and dont get back to their nests.

So throw in that in the last yr bee keeping , in particular in urban built up areas has increased dramatically, this may have an influence ???

Before any one may ask.. the bee hives are good.. I can dig / plant/ weed, and harvest around.. right next to them nps.. The bee guy comes in, I can watch chat to him within a couple meters of the hive.. he rarely uses the smoke.
The cropping on the grapes, tomatoes , persuims, plums, apples, not just our gardens but neighbours has dramatically increased..
The honey... urban honey.. really nice has a unique very pleasant, soft, flower fruity flavour.. which has been quite a surprise.
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