WASPS by the hundreds but no nest! What is going on here...

[einsteinagogo]

What is going on here...

It would appear wasps are being attracted to the Victoria plum tree, but there is no fruit, it's a young tree, and still waiting for it to fruit, otherwise it gets chopped down.

the wasps walk all over the leaves, and then fall off, onto the greenhouse below, sort of dazed, slow, cannot fly for a while

this has happened for the last 3 years, I always though they were attracted to the hot greenhouse glass panes, but after watching and studying they climb all over the plum tree and then fall off...

maybe they are expecting plumbs, and tired ?

I don't know - any ideas ?

I've got a video if it makes any more sense...

https://youtu.be/Vt30N8fxntg

(hosted at YouTube)

 

[Beefriendly]

Plum trees leafs have extrafloral nectaries on the upper surface of the petiole and very close to the base of the leaf. That is what is attracting the wasps. presumably something in the secreted sap is then affecting their ability to fly....narcotic plum sap?
Suck it and see...what happens

 

[Karol]

Is there a smell of oil of wintergreen?

Have you treated the plum tree with anything like:

https://www.ncbi.nlm.nih.gov/pubmed/29105771

Mating wasps will aggregate around plants with high levels of methyl salicylate presumably because the smell is similar to their sex pheromones. The fact that only one pain of glass is involved suggests something might have been sprayed that contains salicylates.

 

[Millet]

Have you checked the plum trees for aphids.. if they have aphids/ greenflies the wasp may well be gorging themselves on aphid poop..

 

[Beefriendly]

Have you checked the plum trees for aphids.. if they have aphids/ greenflies the wasp may well be gorging themselves on aphid poop..

Close....the extra-floral nectaries found on plum, cherry and laurel trees secrete sugary solutions directly. This is what the wasps are attracted to in their "sweet feeding " phase.
No aphids required.
The aphid poo kicks in on trees like Lime etc where there are no extra-floral nectaries but the aphids tap into the sap on the leafs.

 

[Karol]

Aphids are always a possibility but the wasps would be congregating more on leaf/branch stems which they don't appear to be doing. If this is a short episode as the OP suggests then it's more indicative of a mating event which will only last a couple/three days. Feeding off aphids tends to be a more prolonged activity and I would have expected to see more sap on the glass pains.

 

[Karol]

Close....the extra-floral nectaries found on plum, cherry and laurel trees secrete sugary solutions directly. This is what the wasps are attracted to in their "sweet feeding " phase.
No aphids required.
The aphid poo kicks in on trees like Lime etc where there are no extra-floral nectaries but the aphids tap into the sap on the leafs.

Quite forgotten about EFN's. Thank you. They don't normally play much of a role in wasp feeding except in periods of drought so it fits. Lime tree leaves exude sweet sap regardless of aphids so are always a problem. Interestingly, rainfall that washes of the sap off leaves can mobilize wasps by interrupting their programmed feeding. Upshot being that hives are most at risk immediately after heavy rainfalls if they are in the vicinity of sweet sapping plants.

Wasps falling about is not unusual during the sweet feeding season because the quality of the carbs in fruit juice/sap isn't brilliant compared to the trophallactic liquid regurgitated by wasp grubs during the hunting phase so wasps don't have the same energy reserves to fly well which makes them appear dopey/drunk and less likely to get out of the way causing more stings on contact.

 

[jenkinsbrynmair]

My plums are a bit sticky today as well - I just put it down to the humid conditions

 

[einsteinagogo]

Thanks everyone for the replies...

I learn something everyday, and to answer

1. no aphids - that was my first thought so I looked.
2. no water or sprayed the plum tree
3. not sprayed the glass panels on the greenhouse.

they do appear to fall off the tree onto the glass, run around, and "fight" if it's fighting or mating..

 

[Finman]

mmmmmmmm

 

[Erichalfbee]

Thanks everyone for the replies...

I learn something everyday, and to answer

1. no aphids - that was my first thought so I looked.
2. no water or sprayed the plum tree
3. not sprayed the glass panels on the greenhouse.

they do appear to fall off the tree onto the glass, run around, and "fight" if it's fighting or mating..

Friday Night.....Drink and Fight

 

[philipm]

I've been sawing up a large ash tree that we had felled in the garden the wasps are all over the freshly sawn bits, after the sap I assume.

 

[Beefriendly]

Friday Night.....Drink and Fight

Every night is Friday night on this forum

 

[Karol]

Thanks everyone for the replies...

I learn something everyday, and to answer

1. no aphids - that was my first thought so I looked.
2. no water or sprayed the plum tree
3. not sprayed the glass panels on the greenhouse.

they do appear to fall off the tree onto the glass, run around, and "fight" if it's fighting or mating..

Couldn't see that clearly from the vid but the wasps did look like they might be queens and drones.

 

[Bee Bumble]

just after the sap exuded from extra-floral nectaries and dripping onto glass. Nice Buzzard by the way.

 

[einsteinagogo]

Fascinating, YouTube has finished processing the HD version now, if you've not watched the HD version. (1080p).

They all look like Wasps to me, I'll have to look harder, to be honest with you, I try and stay away from the greenhouse, when they are like this, they get a bit grumpy...

Yes, I' ve been trying to take pictures of

1. The Buzzards
2. The Red Kites

which visit daily, and sods law I just capture the Buzzard in the background on the phone! I did see it in the sky and ran in to get my camera but i had gone. I noticed when I watched the video I'd caught it!

 

[Gilberdyke John]

Thanks everyone for the replies...

I learn something everyday, and to answer

1. no aphids - that was my first thought so I looked.
2. no water or sprayed the plum tree
3. not sprayed the glass panels on the greenhouse.

they do appear to fall off the tree onto the glass, run around, and "fight" if it's fighting or mating..

I've had a sudden onslaught of wasps here. There's a nest in a dyke bank about 50 metres from my Apiary and another under the tiles over our utility room. Ficam W is ordered but in the meantime I've placed plastic bottle traps at positions away from the Apiary. Low efficiency but escapees can tell their friends about that location.
The traps are needing very regular emptying!

 

[Karol]

Because the plumes from your hives and the traps that you've set are so far apart the traps will have little if any effect on those scouts that stumble upon your hives first. All that will happen is that you'll create swarm feeding at a remote location without protecting your hives. Those scouts that penetrate your hive will then communicate the location of your hive and those recruited wasps will simply ignore your traps. Meanwhile, if for any reason access to the low efficiency traps is denied, for example they dry out or get overfull, the swarm you've created will go looking elsewhere which could mean you're hive being attacked on mass. Never known this strategy to work except through coincidence of other factors, e.g. wasps double cycling (2nd round of progeny and return to hunting) giving the appearance of success.

 

[TooBee...]

Is there a smell of oil of wintergreen?

Have you treated the plum tree with anything like:

https://www.ncbi.nlm.nih.gov/pubmed/29105771

Mating wasps will aggregate around plants with high levels of methyl salicylate presumably because the smell is similar to their sex pheromones. The fact that only one pain of glass is involved suggests something might have been sprayed that contains salicylates.

Wait a minute, are you saying that some of us are adding Wasp attractants to our hives (albeit most likely late in the year after the wasp threat has gone)?

 

[Karol]

Potentially, but that late on it is unlikely to be a problem.

The other thing that might be attracting the wasps to the plum tree is leaf damage. I notice from the video a number of leaves that have been chewed on presumably by grazing insects. Leaf damage releases odours that wasps associate with the presence of insect prey so these might be hunting wasps looking for other insects.