Another modeled result, extrapolated all the way from 10 common fruit fly species to everything else in the insect world.
Extreme weather caused by climate change in the coming decades is likely to have profound implications for distributions of insects and other invertebrates. This is suggested by a new study of insects in tropical and temperate regions of Australia.
As climate change is progressing, the temperature of our planet increases. This is particularly important for the large group of animals that are cold-blooded (ectothermic), including insects. Their body temperature is ultimately determined by the ambient temperature, and the same therefore applies to the speed and efficiency of their vital biological processes.
- Fruit flies have been the model for a study that has shown how climate change may affect insect distribution in the future. (Photo: Ary A. Hoffmann)
But is it changes in average temperature or frequency of extreme temperature conditions that have the greatest impact on species distribution? This was the questions that a group of Danish and Australian researchers decided to examine in a number of insect species.
Johannes Overgaard, Department of Bioscience, Aarhus University, Denmark, Michael R. Kearney and Ary A. Hoffmann, Melbourne University, Australia, recently published the results of these studies in the journal Global Change Biology. The results demonstrate that it is especially the extreme temperature events that define the distribution of both tropical and temperate species. Thus climate change affects ectotermic animals primarily because more periods of extreme weather are expected in the future.
Fruit flies were modelled
The researchers examined 10 fruit fly species of the genus Drosophila adapted to tropical and temperate regions of Australia. First they examined the temperatures for which the species can sustain growth and reproduction, and then they found the boundaries of tolerance for hot and cold temperatures.
“This is the first time ever where we have been able to compare the effects of extremes and changes in average conditions in a rigorous manner across a group of species”, mentions Ary Hoffmann.
Based on this knowledge and knowledge of the present distribution of the 10 species they then examined if distribution was correlated to the temperatures required for growth and reproduction or rather limited by their tolerance to extreme temperature conditions.
“The answer was unambiguous: it is the species’ tolerance to very cold or hot days that define their present distribution,” says Johannes Overgaard.
It is therefore the extreme weather events, such as heat waves or extremely cold conditions, which costs the insects their life, not an increase in average temperature.
- Periods of extreme heat and thus drought may be the cause of death for many insects. (Photo: COLOURBOX).
Drastic changes in store
With this information in hand, the researchers could then model how distributions are expected to change if climate change continues for the next 100 years.
Most terrestrial animals experience temperature variation on both daily and seasonal time scale, and they are adapted to these conditions. Thus, for a species to maintain its existence under varying temperature conditions there are two simple conditions that must be met. Firstly, the temperature should occasionally be such that the species can grow and reproduce, and secondly, the temperature must never be so extreme that the population’s survival is threatened.
In temperate climate for example, there are many species which are adapted to endure low temperatures in the winter, and then grow and reproduce in the summer. In warmer climates, the challenge may be just the opposite. Here, the species might endure high temperatures during the dry hot summer, while growth and reproduction mainly occurs during the mild and wet winter period.
The result was discouraging for all 10 species.
“Climate change will result in fewer cold days and nights, and thus allow species to move toward higher latitudes. However climate change also leads to a higher incidence to extremely hot days and our model therefore predicts that the distribution of these species will be reduced to less than half their present distribution”says Johannes Overgaard.
“In fact, our predictions are that some species would disappear entirely in the next few decades, even when they have a fairly wide distribution that currently covers hundreds of kilometers”, adds Ary Hoffmann.
“Although none of the 10 species studied are normally perceived as either harmful or beneficial organisms for human society, the results indicate that distribution of many insect species will be changed dramatically, and it will probably also apply to many of the species that have particular social or commercial importance “, ends Johannes Overgaard.
Source, Aarhus University: http://scitech.au.dk/en/roemer/feb14/ekstremt-vejr-afgoer-insekters-udbredelse/
Oh, my, it is worse then we thought.
1) these people should get out more and see insects in nature not only the ten fruit flies in their box.
2) they used as base for their study a modelled (climate changed) future.
How was that model validated? We have saw several times here on WUWT that 95% of models are garbage when tested against reality.
I am ready to blind bet that they used one of the bunch with predictions that go into Nirvana as base for their study.
So somebody financed a study to work based on a flawed climate model?
Why did the people waste that money to make a study based on a flawed climate model? First validate the climate models then do the further study?
Letting the students play role playing games would have been more valuable then this.
Again and again and again the west is trapped in this maelstrom of climate change studies which devour a huge amount of money and deliver only garbage.
Instead of research we finance “research”. And the consequence is that there is no money for other studies. Real studies.
izen says:
February 21, 2014 at 6:34 am
the present rise in sea level, atmospheric humidity and temperature also exceed the rate experience for the whole of human civilisation when the holocene has otherwise been uncharacteristically stable in its climate for over 8000 years. A stability that may well explain the rise of human civilisation based on intensive collaborative agriculture.
oh my the Marcott et all study you link to did not capture rapid variations of climate and you know that.
You know the 8.2 even is well documented, but of course you would like to deny that:
http://www.ncdc.noaa.gov/paleo/abrupt/data5.html
I can’t believe this sort of nonsense is even discussed in “scientific” circles.
Planet earth has multiple infinities of different “environmental niches” , and at the surface level, the range of niche Temperatures goes from -94 deg. C to over 100 deg. C if you count geothermal region lakes etc. Fishes have been photographed right on the bottom of the Challenger Deep at 10,900 meters below sea level. Critters fight to eject other critters from their holes / dens / nests / whatever, and any one vacated, voluntarily or otherwise will soon be snapped up by another critter, of the same species or a different one.
The idea that species are driven around by climate change, is pretty lame. Living things grow where they ca, and easily moveable ones move wherever they want.
Take lobsters for example; not those bitter tasting Maine ones, but tasty spiny lobsters, such as can be found all over the Florida Keys , and many other places.
Everybody knows that you can build a lobster trap with a cage and a hole with inward pointing spines, so the lobsters can easily enter to find the bait you put in there, and then can’t get out, because of those spines.
Total BS. Marine biologists did some experiments (in the keys, where people trap lobsters all the time.) They set out pots in a number of different local places in the keys (strings of pots).
Next morning, they came back, and pulled the pots. Any lobsters they found, were tagged, and left in the pots, back in the water, recording which pots which lobsters were in.
They repeated this every day. The result was, that any lobster could be found in any pot, any day. At night, or in the daylight, they simply climbed out of their pot, and went hunting, and then found a pot to climb into (for safety). Not that they are that safe in there. If humans didn’t come for them, those pots are just octopus cafeterias.
Even plants find a way to move around to find a vacant space where they can get more sun, or nutrients. If there is vacant habitat, uphill from some plant, with less vegetation than downhill, when the plant spreads its seeds to the winds, the downhill ones, may fall on the leaves of some other vegetation, where birds or insects will eventually find them. The uphill ones, are more likely to fall on empty soil, so they can start to grow there. It’s all automatic, and doesn’t have much to do with climate. Just the diurnal weather change on a single day, subjects any critter, plant or animal, to a greater change than the anomalies of the last 150 years, as promulgated by GISS, and UEA CRU , and others.
The humans who spread from the central Asian -istans, to the Southern tip of South America, had absolutely no idea they were going to America.
They just went out hunting one day, and while chasing an animal for food, they found themselves in Mexico. The Bering land bridge was over 1,000 miles wide.
Shouldn’t increased plant growth and changes in the distribution of plant species due to increasing atmospheric carbon dioxide imply corresponding changes in the distribution of insects, even without climate change?
It would seem there lots of bugs in this model.
There are 2 kinds of life that I am least worried about due to global warming. Bacteria and insects. They will be here until it really is the end of life on Earth.
And for the professional eco-worriers who stress about Gaia and life on Earth stop your endless worry. We humans are only on Earth for a blink of a geological eye. Like over 95% of species that ever lived are now extinct, we too will just go poof. Extinction is the norm, not the exception.
Ah, the magic word – “modelled”.
Izen says:
“…the present rate of rise in CO2 in the atmosphere and the consequent reduction of ocean ph is much greater than any past natural event, even the PETM.”
then Izen quotes that paragon of peer reviewed excellence:
https://www.sciencemag.org/content/339/6124/1198.abstract
Izen’s first link says:
…a reconstruction of the links between climate and radiative forcing of the Earth’s surface temperatures… may have been caused by reduced CO2… CO2 concentrations appear to have remained below 500 p.p.m…. And so on.
Izen is hanging his hat on those weasel words, which show that his source isn’t sure about anything at all.
In fact, CO2 has nothing measurable to do with global temperature. Any assertions to the contrary are simply an effort to buttress the alarmist belief in cAGW. But so far, empirical [real world] evidence does not support Izen’s belief in the “carbon” scare.
This doesn’t sound like such a bad study, only the hype is annoying. One major problem is that the 10 species of Drosophila are all closely related. That was a poor choice if one wanted to extrapolate the results to ‘insects’: you can’t. I assume they did this because many Drosophila are easily reared in the lab and because some have been model organisms in genetics, much has been learned about their distributions in the field.
Finding that the response to temperature shocks in the lab match expected high temperatures in the distribution of these species in the field may seem trivial (it does to me), but just because this relationship is assumed to occur doesn’t mean it isn’t useful to see it tested and supported. Obvious problems in interpretation include microhabitat choices in the field that would tend to ameliorate any effect of temperature shocks are not available in the lab and one would expect multivoltine insects such as these fruit flies to rapidly adapt to a new temperature regime. There is also the confounding relationships between temperature and other factors that do not seem to have been controlled for.
Another example of how CAGW poisons everything it touches. This is an interesting minor study that adds somewhat to understanding Drosophila distributions, but has been turned into more magical science.
“izen says:
February 21, 2014 at 6:34 am
Wrong, the present rate of rise in CO2 in the atmosphere and the consequent reduction of ocean ph is much greater than any past natural event, even the PETM.”
Where is the evidence to support that statement?
Which comes after which? Maybe the bugs drive the weather. It’s consistent with the statistics!
And, btw, extremes accompany COOLING. That is the only hypothesis consistent with recent or paleo-history.