Claim: Extreme Climatic Events affect butterfly populations – up and down

From the UNIVERSITY OF EAST ANGLIA and the department of interchangeable lexicon comes this study that may have merit, except they can’t seem to decide if it is weather or climate having an effect by the way they word it.

Research into extreme weather effects may explain recent butterfly decline

Researchers investigated the impact of Extreme Climatic Events (ECEs) on butterfly populations. The study shows that the impact can be significantly positive and negative, but questions remain as to whether the benefits outweigh the negative effects.

While it is well known that changes to the mean climate can affect ecosystems, little is known about the impact of short-term extreme climatic events (ECEs) such as heatwaves, heavy rainfall or droughts.

Osgur McDermott-Long, PhD student and lead author from the School of Environmental Sciences at UEA, said: “This is the first study to examine the effects of extreme climate events across all life stages of the UK butterflies from egg to adult butterfly. We wanted to identify sensitive life stages and unravel the role that life history traits play in species sensitivity to ECEs.”

The researchers used data from the UK Butterfly Monitoring Scheme (UKBMS), a high-quality long-term dataset of UK butterfly abundances collected from over 1,800 sites across the UK, spanning 37 years, to examine the effects of weather data and extreme events (drought, extremes of rain, heat and cold) on population change.

The team looked at resident species of butterflies, those which only breed once in a year, and those having more than one brood annually. Multi-brood species were found to be more vulnerable than single brood species and in general extremes of temperature rather than precipitation were found to influence changes in butterfly populations.

Dr Aldina Franco, co-author said: “A novel finding of this study was that precipitation during the pupal (cocoon) life-stage was detrimental to over one quarter of the species. This study also found that extreme heat during the ‘overwintering’ life stage was the most detrimental extreme weather event affecting over half of UK species. This may be due to increased incidences of disease or potentially extreme hot temperatures acting as a cue for butterflies or their larvae to come out from overwintering too early and subsequently killed off by temperatures returning to colder conditions.”

In addition to the negative impacts, the authors found that some life stages may benefit from climatic extreme weather, with extreme heat in the adult stage causing a positive population change in over one third of the UK species.

Dr Franco, added: “This is not an unexpected finding given that butterflies are warm loving creatures. Years with extreme warm summers and winters may have mixed effects. For example, this year was terrible for butterflies, although the summer was warm the number of butterflies counted during the Big Butterfly Count was particularly low. Our study indicates that this could have resulted from the detrimental effects of the warm winter, for example the recent low counts1 of Gatekeeper, Common Blue, Comma, Peacock and Small Tortoiseshell butterflies could be explained by our results due to their negative response to warm winters which was just experienced2”.

Mr McDermott Long said: “The study has demonstrated previously unknown sensitivities of our UK butterflies to extreme climatic events, which are becoming more frequent with climate change. Some of these effects are undoubtedly putting future populations at risk, such as extremely warm winters, however we’ve seen that warm and even climatically extreme hot summers may actually benefit butterflies.

Further research is needed regarding the balance of the importance that these variables could have, to see if the benefits of warmer summers will be outweighed by the detrimental winter effects”.

Dr Tom Brereton from Butterfly Conservation and a co-author of the study, said: “If we are to mitigate against extreme events as part of conservation efforts, in particular, we need a better understanding of the habitat conditions which can lead to successful survival of adult, pupal and overwintering life stages of UK butterflies in these situations.”


This work is part of Osgur McDermott-Long’s PhD project funded by the University of East Anglia and with Butterfly Conservation and the Biological Records Centre as project partners. Prof Rachel Warren, Dr Aldina Franco and Dr Jeff Price and are the PhD supervisors. External co-authors include Dr Tom Brereton from Butterfly Conservation and Dr Marc Botham from Centre for Ecology and Hydrology.

‘Sensitivity of UK butterflies to local climatic extremes: which life stages are most at risk?’ is published in The Journal of Animal Ecology on 31/10/2016.



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October 31, 2016 3:36 am

But the reduction in the number of butterflies means there are less of them flapping their wings and causing extreme weather events. At least that’s my story and I am sticking to it. It makes as much sense as mainstream “science” often does nowadays.

David Chappell
October 31, 2016 3:51 am

I thought it was butterflies that effected the climate…

David Chappell
Reply to  David Chappell
October 31, 2016 3:51 am

affected… doh

son of mulder
October 31, 2016 3:53 am

On reading the first paragraph of the attached reference I’d suspect that predation masks any other direct weather related affect.

son of mulder
October 31, 2016 3:55 am

effect… doh

Reply to  son of mulder
October 31, 2016 6:55 am

You and David need to coordinate, I believe you are using each other’s words.

Reply to  son of mulder
October 31, 2016 6:39 pm

David, son of mulder, you are both out of date. It’s “impact” all the time now.
(Probably because knowing the difference between “effect” and “affect” gets you called a “grammar Nazi”.)

David Chappell
October 31, 2016 3:59 am

Methinks Osgur McDermott-Long is trying to cash in too soon on his very incomplete PhD project.

October 31, 2016 5:10 am

So the results are give us more work/money. Well it is the University of East Anglia !

Gerry, England
October 31, 2016 5:18 am

I see we have the extreme climatic events increasing money quote in there.
Without the time to fully read the paper, here is a thought that would need looking at. The UKBMS uses the Pollard Walk to record data. There appears to be 4 rules about when these are not undertaken. Not below 13C, not between 13-17C if less than 60% sun are two that interest me as those conditions can occur without extreme climatic events as they say. What effect might this have on the data?

Julian Williams in Wales
October 31, 2016 5:28 am

Many British species of butterflies are at the northern extremes of their ranges, their ranges usually spread south and west across Europe and sometimes into northern Africa where they are usually more abundant and live with hotter drier weather. It is unlikely that more butterfly friendly weather causes the decline in butterfly numbers, especially when there are more obvious reasons such as habitat loss and pesticide usage to look at.
I was reading yesterday about fruitflies in North America that lay their eggs in mushrooms that carry a parasite eggs of nematodes (Howardula) with them in their bodies, the Howardula eggs are laid with teh fruit fly eggs in the mushrooms and hatch and feed on mushrooms and then hitch a lift on the next generation of fruit flies. The nematodes recently came from Europe and make the host fruit flies infertile, but recently the fruit flies have become fertile again even with the Howardula infestations in their bodies. It was discovered that the flies have picked up a second bacterial parasite called Spiroplasma that protects the flies from becoming infertile when they are infected with nematode. The story illustrates a new understanding that symbiotic relationships (especially with phages, viruses and bacteria) are very convoluted and changing very rapidly. These sorts of relationships can be affected by the anthropomorphic transferences of species across continents.
This paper is just another example of finding things to add to the list of awful consequences of “climate radicalisation”

Ross King
Reply to  Julian Williams in Wales
October 31, 2016 9:23 am

You shd send yr 2nd. para. to Dr. “Fruit-Fly” Suzuki. He’s so busy trying to convince The World about the Alarmism and the dangers of AGW (an area way beyond the fruit-fly-sized area of expertise he has) that he likely doesn’t know it.
He shd nit to his sticking.

October 31, 2016 5:40 am

Researchers investigated the impact of Extreme or Not So Extreme Climatic Events (EONSECEs) on butterfly populations. The study shows that the impact can be significantly positive and negative, but questions remain as to whether the benefits outweigh the negative effects. Or not.
While it is well known or unknown that changes to the mean climate can affect or not change ecosystems, little or much is known about the impact of short-term or long-term extreme or not so extreme climatic events (EONSECEs) such as heatwaves/frosts, heavy rainfall or droughts.
Osgur McDermott-Long, PhD student or undergraduate and lead or tail author from the School of Environmental Sciences at UEA, said: “This is the first or last study to examine the effects of extreme or not so extreme climate events across all or a few life stages of the UK butterflies from egg to adult butterfly. We wanted to identify or mis-identify sensitive or not so sensitive life stages and unravel the role that life history traits play or fail to play in species sensitivity to EONSECEs.”

Steve Fraser
Reply to  Admad
October 31, 2016 6:05 am

Gotta love it!

October 31, 2016 6:03 am

” extreme climatic events, which are becoming more frequent with climate change”

Reply to  DaveS
November 6, 2016 10:56 am

Are “extreme climatic events” climate “science”-speak for what we normal mortals refer to as “weather”?

Smart Rock
October 31, 2016 6:12 am

The study has demonstrated previously unknown sensitivities of our UK butterflies to extreme climatic events

What on earth is an “extreme climatic event”? We’ve been hearing a lot about so-called extreme weather events, but I can’t see any normal person regarding an “event” as related to climate (as opposed to weather).; and then Osgur went on (predictably) to say:

, which are becoming more frequent with climate change

I hope he’s going to give a reference to support this statement, or does he assume that this is something that “everyone knows” to be true?

October 31, 2016 7:39 am

Population dynamics are inherently chaotic.
This is first class of the first year of undergraduate ecology.,%20&%20evolutionmay.pdf
“Climate change (climate is always changing because it’s chaotic) causes butterfly populations (which are also chaotic and always changing) to … CHANGE!”
What is the null hypothesis here? How does on propose to test it?

October 31, 2016 7:39 am

Insects life cycles do respond to small degree temperature & relative humidity. This includes egg laying & survival rates. These factors have long been studied for certain kinds of insects & not surprisingly the original post recognized this is the case for different kinds of butterflies.
“Extreme” characterization is, to me, the spurious concept here. I don’t have the time now to review specific varieties of butterfly, so can not give examples of known temperature range &/or relative humidity influence on specific butterfly life cycle. Still, I am confident the UK buttrrflies are not in danger of extinction & a weather change can reverse the reported trend; so that the population of at varieties currently down in numbers will go up & varieties currently up in numbers will go down.
I am skipping the importance of what they find to eat at relevant times, which can influence an insect egg. Weather also impacts vegetation cycles & insect diet affects what can easiest be categorized as fecundity. There is also variation in insect population dynamics related to whether dealing with previously mated females or virgin female insects.
Original post also seems to gloss over pathogens. Different kinds of the same insect can be susceptible, or not at all, to a specific pathogen(s). Pathogen populations themselves can be influenced by temperature & moisture. I am also skipping the dynamics of insect pathogen virulence.

Reply to  gringojay
October 31, 2016 9:02 am

Good bit of background analysis, Gringojay.
I will look forward to reading the paper when I’ve more time, but I’m thinking that any paper that treats butterflies as a group will likely dilute and obscure the more interesting observations that might be made regarding individual species and weather, where good work can and is sometimes done, often by amateurs.
If they have tried to link weather ‘events’ to butterflies at the species level, then I will withdraw my reservations.
Just a few things to bear in mind
– We have little more than 50 species here in UK, far fewer than comparable areas elsewhere. This may be partly due to the influence of unpredictable atlantic weather patterns, and partly to the isolation of this island from continental Europe.
– The abundance of a species in one year, as with most insects, is a very poor predictor of the abundance the following year. A potential reproductive capacity of 200-500 times per generation ensures vast swings in numbers, and teasing out the various elements which contribute to these cycles in quite tough. The influence of parasites (parasitoids if you wish to be picky – though spellcheck doesn’t seem to recognise the word!) can hardly be overestimated and is for many species likely the limiting factor.
– The data on which it is based are drawn from records of very many enthusiastic amateurs, of varying observational acuity, deputed to walk the same stretch of country 1 – 4 times per month between April and October, at times and in weather of their own choosing. If they miss out due to weather, infirmity, or because there is something good on the telly, it still counts. Okay, it’s the best we have, but it is not great. Sometimes butterflies appear entirely absent one year, but they are there in numbers the next. How did we miss them?
– With butterflies, as with most insects, the greatest species diversity is to be found in the south and east of the country, that is the area that is most influenced by ‘continental’ climate, and it would seem that winter cold (perhaps early winter cold most of all) is a greater determinant than summer warmth. The milder climates of the southwest have fewer insect species, though there are specialists which flourish in those conditions
– They are probably wise to try to associate changes with ‘extreme’ weather events rather than ‘global warming’ per se, as I guess you could always find some plausible results by this stratagem. If by any chance global warming were to influence the butterfly biodiversity directly, it could hardly be other than positive!
May get back later

Reply to  mothcatcher
October 31, 2016 10:16 am

Some examples of how weather affects insects:
Beetle Tenebrio molitor larvae do best in 80% relative humidity, their pupae do best in 90% relative humidity, oviposition (egg laying) is bedt in 90% relative humidity & eggs hatch quickest in 75% relative humidity. Their larvae grow fastest at 20-25°C & although 34°C is the threshold for impacting oviposition a superior diet is essential for robust oviposition over 30°C. Relative to 25-29°C at a higher temperature the number of progeny/week increases in the initial 21 days of a female’s breeding life; but will decline faster than otherwise at lower temperature after ~ 28 days.
Crickets in Australia provide another nuance on weather. Teleogryllus commodus in different region weather may, or may not, require a period of diapause (like an egg hibernation); although they go through 9 moults no matter where they live. Queensland strains’ eggs do not require diapause as much as southern strains when temperatures hit 28°C. For this cricket there might be 20-80 days incubation needed as temperature rises from 20-30°C . At 35°C their eggs do not seem to diapause.
If the eggs have not already gone into diapause then 5°C for over 3 weeks causes the eggs to die & it takes only 2.5 days at 0°C for the eggs to die if not in diapause. However, if the eggs are actually in diapause they can survive 5°C for 2 months.

Charlie Adamson
October 31, 2016 8:16 am

Wow Anthony,.. Great Catch. This type of “research” really needs to be brought to light.
That being said,.. it is now officially proven that The University of East Anglia is really a mental-emotional asylum which specializes in creating children that are totally incapable of living their lives as complete and whole fully individuated people. Once again they have demonstrated what looks like a total educational “FAIL”, but awards students with gold stars, “atta-boys” and “you-go_girls” instead, so they can feel good about their non-existing/non-developed selves.
This institution is getting away with stealing the only task that children have to be concerned with, namely the hard work involved in what it takes to develop inner self guidance and autonomy. Truly these are generations lost to lives of total dependency, dependency on others thinking for them leaving them totally vulnerable to being controlled. History of others who have done the same show that they will be the first ones that are thrown under the bus, when everything crashes down. And they always collapse. Protected from having to face failure they are sentenced to live failed lives.
What ever happened to the original meaning of the word education?_(education: to draw out).
Sorry,.. but I just had to say something, even if it was only words pointing out the obvious fact that the Emperor has no clothes as well as nothing of value in and of himself to offer the people. Thanks for the opportunity to get this out. I’m sure that you too often feel the same way. Rest assured Anthony you are not alone. Many of the people who love your efforts here at WUWT are very grateful to come to know you, even if it is just over the Internet.
I too am Grateful.

October 31, 2016 8:52 am

“Research into extreme weather effects may explain recent butterfly decline.”
So the research causes the butterfly decline? Is this like the frogs that declined due to researchers bringing in a toxic fungus? Just asking.

October 31, 2016 9:03 am

Well Glad to see a love of nature and a desire to protest its species. I think a life ahmed with such love is great. That’s what the simplist site tell you. Keep on being happy

October 31, 2016 11:56 am

Butterflies. How ironic. Lots of helping papers to that, too, not treating chaos in weather and climate, but in population dynamics, too. Here is one example:

michael hart
October 31, 2016 4:36 pm

And in another research group someone will be blaming neo-nicotinoid pesticides for the same phenomenon. The BBC will happily report both at the same time.

November 1, 2016 3:12 am

Research into extreme weather effects may explain recent butterfly decline

And the number of hurricanes isn’t increasing. Coincidence? I think not.

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