Wasps

[Dishmop]

I just stunned a wasp which was sniffing around a hive looking for a takeway..

and put it on the landing board for the bees to play with.

 

[Karol]

"average maximum temperature ranges between 20 - 30ºC and in winter between 10 - 15ºC."
is dramatically different to;
"Winter temperatures in NZ range from 10° to 15°C".
If you cannot see that then you are quite right, theres no point arguing the toss.
Parts of the South Island are popular with Kiwi's for skying and even in the far North of the North Island its not unheard of to have sharp frosts.

You're quite right to pick me up on the difference between the two. Except that it is the maximum average temperatures which influence wasp behaviour. Vespine wasps are quite comfortable with the odd frost or two. I didn't realise that the NZ papers were reporting on beech forests at such high elevations and such cold temperatures!

Again, with the 4 to 5 tonnes of foraged insects, do you not think even a modicum of accuracy is necessary for an informed discussion ?
You may feel this is realistic and worth rebroadcasting as if its fact, but anybody with a pencil and a bit of paper coupled with a few real facts about seasons and daylight hours, individual wasp payloads and average wasp nest populations can quickly calculate that it would only be close to possible if the wasps did little else, truth is they spend as much time housekeeping or just hanging out at the nest as bees do, so the figure is way over the top, possibly by an order of magnitude or two.

Real facts?

I'm happy to be educated mbc and I'd be delighted if you could elucidate what the 'real' facts are.

I suspect what you are really talking about are assumptions.

 

[wood blewit]

I love the chance to eat outside on a lovely summer eve an we have had plenty this year , but as said the wasps have been a bit of a nuisance more than once I've shared me sirloin with a couple of hungry wasps taking advantage of an easy opportunity i just left em to it as i ate they landed cut off tiny little segments of meat an took em bak home returning every five minutes for some more i let them be and they let me be quite interesting really , as for my hives they've been pestered but seem to be able to hold there own against the jaspers especially the AMMs they really get stuck in .

 

[Chris Luck]

We always give them their own plate.



Chris

 

[PBee]

....I am happy to defend my position that I believe that 4-5 metric tonnes is a realistic figure .........

Another way of calculating the figure;

Day light hours in June approx 16 hours. Each flight = 30 minutes. 32 flights per wasp per day. 5000 foragers in maturing nest = 160,000 hunting flights per day. Average weight of wet insect (e.g. caterpillar) = 1g. Average weight of dry insect (e.g. bee) = 0.1g. Working on 0.5g per flight average gives 80Kg per day or 2.4 metric tonnes in June. Wasp hunting season is weather dependent and lasts from April to the end of July (normal season) or as late as end of October (delayed season).

It's quite easy to see that 4 to 5 metric tonnes is not an extraordinary figure.

So, to corroborate the numbers;

16 daylight flying hours in Summer = say 100 trips per wasp per day.

For 5000 foraging wasps.

500,000 trips per day. Carrying load between 0.05 and 0.08g per flight = up to 40Kg per day.

The rest is weather dependent.

It's not difficult to see that 4-5 metric tonnes is not unrealistic

I think the New Zealand research is valid, calculations designed to arrive at an arbitrary figure are no substitute for peer reviewed science.

........

I've already said that I don't feel confident about comparing wasp behaviour between the two countries because environmental conditions are so different and environmental conditions have an impact on the biology of wasps. Winter temperatures in NZ range from 10° to 15°C and food remains abundant throughout both of which favour 2 year colony survival (germanica). This clearly will have an impact on the extent of sweet feeding that is seen at different periods in the year.

Overwintering is restricted to germanica in NZ, except for isolated cases of vulgaris, and seems to occur in only around 10% of colonies. Vulgaris has displaced germanica from the beech forests due to a more efficient honeydew foraging technique.

On average, 10% of V. germanica colonies overwintered, similar to the 11.3% estimated from nest destruction records for Nelson City in 1988 (Plunkett et al. 1989).
No overwintering V. vulgaris colonies were found in this study. Several overwintered colonies of V. vulgaris have been recorded in New Zealand (Plunkett et al. 1989; D. Leathwick & P. Godfrey unpubl. data), but these were not typical of over- wintered colonies as no queen cells were produced until the end of the second season and only one queen was present.
Frequency of overwintered Vespula germanica (Hymenoptera: Vespidae) colonies in scrubland‐pasture habitat and their impact on prey (Harris 1996)

V. vulgaris appears to have competitively displaced V. germanica (Fabr.) in an invasion front during 1986–87, because of the superior foraging efficiency of the common wasp for honeydew (Harris et al. 1991; Harris, Moller & Winterbourn 1994). Elsewhere in New Zealand both introduced wasp species are widespread. http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2656.2002.00630.x/full

 

[Karol]

I think the New Zealand research is valid,

I agree, the NZ research is valid but as with any research work it has its limitations. Understanding those limitations helps in understanding the value/context of the research.

calculations designed to arrive at an arbitrary figure

Not arrive but 'test'. And the figure is arbitrary only because the reference source is buried in an archive of several hundred papers and (my) life's too short to trawl through them (at this juncture at least).

are no substitute for peer reviewed science.

I agree. But I'm not looking to 'substitute' calculations for peer reviewed science. I've used calculations to check the veracity of a figure obtained from a peer reviewed source and I'm happy that that figure is realistic.

Peer reviewed science is no utopia. According to 'peer reviewed science' the world was once flat. Peer reviewed science failed to prevent the withdrawal of dozens of drugs from the market place when it (the peer review science) was found to be wrong.

Overwintering is restricted to germanica in NZ, except for isolated cases of vulgaris, and seems to occur in only around 10% of colonies.

which will still contribute millions of workers and have a noticeable impact. I believe in one of the papers you cited that the paper claimed that overwintering nests contributed 50% of the foraging population. Don't profess to know how that works without qualifying the conditions under which that happens.

Vulgaris has displaced germanica from the beech forests due to a more efficient honeydew foraging technique.

Hmmmm! I would be very surprised if it were down to foraging technique. In the UK we see oscillations in the prevalence of the relevant species and this seems to be more a factor of climactic conditions rather than successful competition. Germanica tends to be a low level nester and is commonly found in the ground. Vulgaris tends to be found nesting higher up. The germanica population in the UK was decimated by our recent wet weather giving rise to an explosion in vulgaris and other tree varieties (sylvestris etc). It may well be that vulgaris is prevalent in beech forests in NZ but I suspect that that has more to do with preferrential nesting habitat rather than foraging technique.

 

[PBee]

I've used calculations to check the veracity of a figure obtained from a peer reviewed source and I'm happy that that figure is realistic.

The figures used in the calculations have to reflect the measured parameters of wasp biology which already exist. Your first calculation used 0.5g/flight which is obviously impossible and the second used a totally unrealistic frequency and proportion of insect prey flights for a worker population over twice the size of the recorded average. Mathematically possible and biologically feasible are two different things.

Hmmmm! I would be very surprised if it were down to foraging technique. In the UK we see oscillations in the prevalence of the relevant species and this seems to be more a factor of climactic conditions rather than successful competition. Germanica tends to be a low level nester and is commonly found in the ground. Vulgaris tends to be found nesting higher up. The germanica population in the UK was decimated by our recent wet weather giving rise to an explosion in vulgaris and other tree varieties (sylvestris etc). It may well be that vulgaris is prevalent in beech forests in NZ but I suspect that that has more to do with preferrential nesting habitat rather than foraging technique.

Apparently germanica was present in the beech forests until after vulgaris arrived. They are still widespread and coexist in other areas of NZ, so weather effects on ground nesting seems unlikely.

 

[Karol]

The figures used in the calculations have to reflect the measured parameters of wasp biology which already exist. Your first calculation used 0.5g/flight which is obviously impossible

Quite possible. You are conflating weight at kill with payload. They are two very different things. The first calculation used weight at kill. The second calculation used payload. The figure I quoted was 4-5 metric tonnes 'eradicated' which translates to weight at kill. The video below might help you to visualize what I'm talking about.

[ame="http://www.youtube.com/watch?v=X4DWQLYoyF8"]Wasp attacks and decapitates moth - YouTube[/ame]

and the second used a totally unrealistic frequency and proportion of insect prey flights for a worker population over twice the size of the recorded average.

Frequency was taken from; http://www.insectscience.org/11.103/i1536-2442-11-103.pdf. Any problem with that?

What was the sample size, time and distribution that generated this 'recorded' average PBee?

Mathematically possible and biologically feasible are two different things.

Always assuming that one isn't comparing apples with cabbages.

Apparently germanica was present in the beech forests until after vulgaris arrived. They are still widespread and coexist in other areas of NZ, so weather effects on ground nesting seems unlikely.

As for vulgaris vs germanica in beech forests in NZ I don't suppose you have any corroborating references post 1991?

[ame="http://www.youtube.com/watch?v=EgxdIeooSp8"]Wasp taking honeydew in a New Zealand beech forest - YouTube[/ame]

Interesting that this is germanica foraging off honeydew in a beech forest in 2010. Not conclusive by any stretch of the imagination. But it ties in with the discussions I had only two weeks ago with an entomologist in NZ who was quite clear about germanica being a problem in beech forests. Difficult to know what to think or who to believe. Like I said, I'm not confident about wasp behaviour in NZ because it's very different to what we have here.

 

[AdrianSmith]

the figures used in the calculations have to reflect the measured parameters of wasp biology which already exist. Your first calculation used 0.5g/flight which is obviously impossible.

quite possible
You are conflating weight at kill with payload. They are two very different things..

I'm a bit lost in this argument now, but the above exchange seems to highlight part of the problem. One person is arguing about what's possible, and another is questioning something described as "an average".

Any scientific work which results in an interaction will skew results. The figure of 4-5 metric tonnes itself is not so important - angels and pin heads etc. What is important is that the figure is 'large' and has a significant ecological impact. What is also important is that wasps need to be valued and that control of wasps needs to be judicious and sustainable.

A figure used to demonstrate the ecological importance of wasps should be multiplied by the average number of wasp nests in a given area to get a meaningful figure.
If a figure of 4-5 metric tonnes was possible, but the real average was a factor of 2 less than that, then you could say "sustainable" meant killing anything less than
1/2 of the wasp nests.
It's quite interesting to wonder about how much "slack" there might be in this part of the workings of the natural world.

 

[mbc]

aa
aa

Alcoholics anonymous ?
African american ?
automobile association ?
adventurous aardvark ?
alternative apiary ?

Give us a clue.

 

[AdrianSmith]

Alcoholics anonymous ?
African american ?
automobile association ?
adventurous aardvark ?
alternative apiary ?

Give us a clue.

Sorry, busy getting kids to bed. I hit "submit" rather than "preview". I've hastily edited it, but don't think I quite got it as I wanted.
Never mind
Has anyone else ever wondered if there'd be more butterflies and other pollinators if it wasn't for us beekeepers?

 

[mbc]

Has anyone else ever wondered if there'd be more butterflies and other pollinators if it wasn't for us beekeepers?

Its a good question and is a compelling reason why we should be careful not to keep overly large populations of honey bees in a given area by propping them up with outside inputs ie. too much sugar feeding.
On the other hand its a bit of a win win situation with regard to pollinators and plants, the more plants that get properly pollinated the better they do in the future and the more plants there are for pollinators to forage on. I doubt if it often occurs that other pollinators go short of nectar as a direct result of honey bees harvesting every last drop.

 

[AdrianSmith]

A figure used to demonstrate the ecological importance of wasps should be multiplied by the average number of wasp nests...
.

Doh. Of course I meant "should not".
If someone said

"There was a 30 stone person in the waiting room of that hospital.
There are 3000 people in that hostpital.
People alone contribute up to 30*3000 stone to the weight on the foundations"​

You would be right to question the "up to". That figure will ne an upper limit, but not meaningful in any other way.
The same aplies to individual grams per flight figures too.

 

[Chris Luck]

Its a good question and is a compelling reason why we should be careful not to keep overly large populations of honey bees in a given area by propping them up with outside inputs ie. too much sugar feeding.
On the other hand its a bit of a win win situation with regard to pollinators and plants, the more plants that get properly pollinated the better they do in the future and the more plants there are for pollinators to forage on. I doubt if it often occurs that other pollinators go short of nectar as a direct result of honey bees harvesting every last drop.

+1, it's all in the habitat.

Chris

 

[PBee]

Quite possible. You are conflating weight at kill with payload. They are two very different things. The first calculation used weight at kill. The second calculation used payload. The figure I quoted was 4-5 metric tonnes 'eradicated' which translates to weight at kill.....

Like I said, I'm not confident about wasp behaviour in NZ because it's very different to what we have here.

Wasp colonies have a division of labour amongst the adult population just like bees - but on a much smaller scale where annual colonies are concerned as in the UK. The divisions in the foraging adults - as opposed to the brood nurses and guards are remarkably similar as measured scientifically in England by Archer and in NZ by Harris et al.

During a colony's existence, 27.5% of the outgoers are earth carriers, and of the incomers,12.2% are pulp carriers, 12.0% flesh carriers, 72.2% fluid carriers, and 3.1 % empty incomers. http://link.springer.com/article/10.1007/PL00001689

A total of 7225 foragers were caught in the entrance traps at the two sites, of which 838 (11.6%) carried prey, 5.4% carried wood pulp, and 83% carried no external load. http://www.nzes.org.nz/nzje/free_issues/NZJEcol17_1_5.pdf

In the latter paper the average peak traffic rate for all foragers was ~ 38/minute.

The average traffic rate at peak was similar for the two species (38.4 for V. germanica and 36.8 for V. vulgaris).

It comes back to the your original contention that wasps do not forage (non insect) carbohydrate to the nest and the 'exclusive' hunting phase/sweet feeding phase hypothesis, which is not reflected in the literature.

 

[Karol]

Wasp colonies have a division of labour amongst the adult population just like bees - but on a much smaller scale where annual colonies are concerned as in the UK. The divisions in the foraging adults - as opposed to the brood nurses and guards are remarkably similar as measured scientifically in England by Archer and in NZ by Harris et al.




In the latter paper the average peak traffic rate for all foragers was ~ 38/minute.

It comes back to the your original contention that wasps do not forage (non insect) carbohydrate to the nest and the 'exclusive' hunting phase/sweet feeding phase hypothesis, which is not reflected in the literature.

This is I believe the relevant excerpt from the first paper you quote:

"Foraging studies were made of seven colonies situated near York,
England. During 1970, Grange Wood 70 and Pasture Wood 70 were
observed at seven day intervals from early July until mid-September.
Counts of full and partial fluid carriers were not made during 1970.
During 1 974, Sand Hutton (I) 7 4,Sand Hutton (2) 7 4 and Pasture Wood
74 were observed at about three day intervals from mid-July until early
August, and except for Sand Hutton (l) 7 4, from late August until early
Octbber. During 1978, Garden 78 was observed at two day intervals
from the beginning of July until early August. In early August, the
colony Garden 78 showed early signs of failing, so only the counts from
early July from this colony have been used. During 1982, Brandsby 82
was observed at two day intervals from the middle of June until the
middle of July. The colony Brandsby 82 started to fail from21 June and
foraging ceased on 23 July, so only the early June counts from this
colony have been used."

This is the relevant excerpt from the NZ paper;

"Four nests at
Mystery Creek and five at Ruakura were trapped by
collecting samples in an inner collecting tube (Fig.
1) over 32 days between 16 January and 19 May
1992."

Interesting that both papers sample nests during (ostensibly) the sweet feeding phase of the nest. Perhaps you can explain how that is representative of the bulk of the nest development phase? And the figures you quote are 'hypotheticals' (not actuals) extrapolated from the sample data onto the whole life of the colony. I'm not sure how scientific that is?

The sample sizes are also biased because they are small in number and because they are underground nests which from experience are much smaller than nests found in buildings where energy is not expended on excavation.

It's also interesting that a number of the sampled nests failed. It is highly unusual for nests to fail so late in the season which suggests that the sampling method may have interferred with the results.

I wouldn't read too much into the 38/minute rate at that time of year/life cycle because workers will have switched from 'foraging' to feeding so spend more of their time away from the nest. What foraging is done will be diminishing and probably minimal to support that last vestiges of any grubs remaining in the nest and that won't be that many at that time of year (depending on the weather).

 

[PBee]

.......... It's not the cold that kills off declining workers - it's starvation. In the UK we still see wasp activity right up to January (up to 6 months sweet feeding activity post nest maturation) where there's food available. ...........

Is it not (unlike honeybees) a finite lifespan that kills off declining workers?

There are only direct observations of the length of life of workers for P. vulgaris. During June workers live 12.4 days (range 5-26 days) (Spradbery, 1971), during July 13.6 days (2-27 days), August 22.3 days (8-37 days), September 17.4 days (4-29 days) (Potter, 1964), and during August and September 10.3 days (1-37 days) (Archer, 1981). The higher values of Potter were observed in a heated laboratory colony where worker length of life might have been prolonged. http://www.academia.edu/1463476/Archer_2008a_Taxonomy_Distribution_and_Nesting_biology_of_the_species_of_the_Genus_Paravespula_or_the_Vespula_Vulgaris_group_Hymenoptera_Vespidae_

 

[Karol]

Is it not (unlike honeybees) a finite lifespan that kills off declining workers?

My understanding is that all organisms have a 'finite' life span, it's just that it's variable depending on smoking, dietary and drinking habits! :0)

The meaningful study of wasps is incredibly difficult and I take my hat off to those that have tried because their work has provided valuable insight. Nevertheless, it has to be understood that there is a high degree of uncertainty in much of the published work because of limitations in sampling and what I would call cycle 'relativity'. As humans we like to order and pigeon hole processes into 'discrete' packets. Nature isn't like that. Trying to relate the life expectancy of an adult worker to the amount of meconia (feccal pellets) found in the nest doesn't seem to me to be a necessarily robust method not least because it doesn't account for any excretion taking place outside of the nest as the activities of adults change during the different phases of nest development and subsequent nest decline which is when workers spend most of their time sweet feeding (and therefore pooing) away from the nest.

So in answer to your question, I would have to say that it is my experience that it is starvation that ultimately brings about colony decline (in the UK) and this is closely linked to when the last of the ivy stops flowering in November.

 

[sharonh]

Yes, wasps still around and plentiful. All over the ivy right now, have also seen some in my polytunnel catching flies and other insects while in flight.
At least they are leaving my bees alone now. That wasp bane trap did the job.
Found this year particular bad with wasps around here,
I will be better prepared next year in the event that it could be just as bad.

 

[PBee]

........ Trying to relate the life expectancy of an adult worker to the amount of meconia (feccal pellets) found in the nest doesn't seem to me to be a necessarily robust method not least because it doesn't account for any excretion taking place outside of the nest as the activities of adults change during the different phases of nest development and subsequent nest decline which is when workers spend most of their time sweet feeding (and therefore pooing) away from the nest.
......

The meconia are of larval origin only and indicate the number of larvae which occupied the cell – only one produced per larva. The figures for worker lifespan are ‘direct observations’ and there seems to be broad agreement on the range.

..... During the sweet feeding phase (mature nest with no grubs) adult wasps are solely interested in sweet liquid foods.

The appearance of carbohydrate foraging (‘nusiance’) wasps coincides with the large cell colony and is described as follows in, Social Wasps, Their Biology and Control (Edwards 1980) ....

… workers of V. vulgaris and V. germanica become pests late in the season (August-September in the U.K.) when wasps visit buildings in search of sweet substances, The reason for this apparent 'change' in habits is three-fold, Firstly, the number of adults in the colony is at its highest and there are many more wasps foraging than earlier in the season, Secondly, there is a very large number of larvae in the nest: these are still fed mainly with animal flesh, but there will nevertheless be an increase in the carbohydrate requirement. Thirdly, newly emerged sexuals require extra carbohydrates to give the males energy for their mating flights and females the fats to keep them alive during the winter....

… In colonies of V. vulgaris the long season permits a slower Increase in numbers, which then remain high for over a month. In both species, large cells are built during peak activity and this is also the time when workers of V. vulgaris become pests around homes and factories (usually starting in August).