Evolutionary straitjacket means flies can’t take the heat
Many species of fruit fly lack the ability to adapt effectively to predicted increases in global temperatures and may face extinction in the near future, according to new research.
In a study published today in Proceedings of the National Academy of Sciences, researchers from Monash University, The University of Melbourne and Danish collaborators showed that many species of fruit fly appear to be constrained within an evolutionary straitjacket and can’t readily adapt to climate change-related temperature increases.
Dr Vanessa Kellermann from Monash University’s School of Biological Sciences said current projections predict a 3ºC increase in mean annual temperature in the next century and even greater increases in extremes.
“Given our findings, these expected increases pose a major threat to biodiversity in the near future. Particularly as Drosophila or fruit fly findings are often more broadly applicable,” Dr Kellermann said.
By examining nearly 100 species of fruit fly from around the world, the researchers showed that species had evolved to the temperature extremes and humidity of their environments. However, they had very little flexibility in being able to change their levels of heat resistance and seem unable to adapt to increased temperatures in the future.
High heat resistance is a feature of only some branches of the phylogeny – the tree that shows how species are related through evolution – of Drosophila. Other branches had very limited ability to change their levels of heat resistance; even when flies native to cooler areas grew up in a warm environment, their heat tolerance was not significantly altered.
“The problem is that only a handful of species have adapted to hot environments while most species have not and it seems very difficult to switch once you are stuck on a phylogenetic branch,” Dr Kellermann said.
The researchers looked at species’ prospects for dealing with projected temperature increases in the near future.
“If a species can only withstand temperatures of 36ºC and the maximum temperature of the environment is already 36ºC, an increase of even 1ºC would already put this species over the edge towards extinction,” Dr Kellermann said.
Using this method, the researchers identified at-risk species and found that most tropical and mid-latitude species fell into this category.
“Without rapid adaptation, which now seems very unlikely, a lot of species may fall over under even a mild increase in temperature,” Dr Kellermann said.
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I’m sure the people who have battled the Mediterranean Fruit Fly will be happy to hear this. It seems though this is just old recycled news used to paint GW in a scary light, here’s a paper from 1986:
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Developmental temperature and life span in Drosophila melanogaster. I. Constant developmental temperature: evidence for physiological adaptation in a wide temperature range.
Abstract
The concept of an inverse relationship between life span of adult Drosophila and their developmental temperature is probably the result of an unwarranted generalization. Rather, in a wild-type laboratory strain the present study revealed a plateau phase in this relationship between 16 and 29 degrees C in which life span of both male and female flies was roughly independent of developmental temperature. Below and above this range, life span dropped drastically, development being impossible below 12 and above 32.5 degrees C. Simultaneous study of growth characteristics showed that the plateau phase corresponded to a ‘physiological’ range of developmental temperature, development being apparently disturbed outside that range. Within that physiological range, the growth rate of the flies varied varied 2-fold, while life span remained constant corroborating our previous conclusion that growth rate per se does not determine life span.
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I find it humorous that Nature so poorly equipped flies over the billions of years of existence that they’ll just “fall over” once the temperature gets to 37C. So much for evolution and survival of the fittest. Contrast this to claims that GW will cause mosquitoes and others pests to flourish.
I wonder where David Suzuki stands on this news?
Louis sept 18 10:57am
Louis says — Its a real conumdrum. If we experience global warming several species of fruit flies may go extinct. But if we don’t several species of climate scientists may go extinct.
Awesome!
Eugene
More dancing round the “may” pole. First, a 3c rise in temp even within a century is pure fantasy. Its 50/50 whether temps will rise or fall over that time. And the 36 C limit is for reproduction and embryonic development, not a temperature that will kill the insects. Animals can adapt their lifestyles for instance becoming nocturnal or finding hotter / cooler micro-climates. Or they can move. For instance chironomus species (gnats) swarm at different heights to differentiate niches for different species at the same location.
Reality is much more complex than this grossly flawed and simplistic study, based on fantastic projections, would suggest.
Will future generations, in a cooler climate, learn any lessons from all this published AGW nonsense filling up archive disc space?
Alfred, Lord Tennyson had this to say about the evoluntionary resolve of fruit flies.
Though much is taken, much abides; and though
We are not now that strength which in old days
Moved earth and heaven, that which we are, we are
One equal temper of heroic hearts
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Charles Darwin would have agreed.
Eugene WR Gallun
Several things to point out: 1) The image is wrong (it’s Ceratitis while the study is about Drosophila), wrong genus, even wrong family!.
2) As I understand, the new study talks about biodiversity risk, as whole species will be extincted, or at least a big amount of genes. This may or may not (most probably, I think) extinct the whole genus, I think that is a newspaper’s idea. The higher risk this imply is, in my opinion, the loose of genes to study in this useful genus.
3) As I understand, the 1986 paper does not necessary deny the above affirmation.
4) The “Queensland fruit” (Bactrocera tyroni) Martin Clark is again, not only a different genus, but this time a different infraorder!!
This is ludicrous. Drosophila are used in genetic research precisely because they mutate so readily and have short life spans.
During the Eemian between about 130,000 and 115,000 years ago the Hippopotamus was was to be found in the rivers Thames and the Rhine. Drosophila was shy and remained seated and fried. It sadly lost the ability to fly or evolve. / sarc
And at the same time we are informed by peer reviewed papers that plants and animals are moving their ranges northwards and uphill. As for “rapid adaptation” fruit flies can fly and they are renowned for their evolutionary speed and diversity on almost all continents. This study is an utter waste of money based on IF. All life has temperature limits.
My Science 101 course studied the fruit fly because it mutated faster than most other species and there were a lot easily caught. Adaptation to change was very evident. i think the claims in this post are alarmist not real.
It seems more logical to me that the fruit fly has evolved for the same temperature tolerance as it’s food source. If the fruit growing in an area cease to be viable then the fly that feeds mainly on that fruit will decline and the fly that feeds on the new fruit increase. Temperatures affect both the fly and the fruit. Find the fruit and you will undoubtedly find the fly. GK
Thanks for posting this. There should be solution for Global warming. Temperatures is increasing day by day. It is very difficult for us to stay in this world if temperature increases at alarm rate. Today I watched documentary film about Global Warming titled ‘The Changing Climate of Global Warming’. I recommend you to watch this if you did n’t watch yet.
http://www.thegreatplanet.com/the-changing-climate-of-global-warming-documentary-film/