Global warming is already speeding up insect breeding

“From a pest perspective it’s an important issue.”

Two butterfly species, the small heath (left) and common blue (right), have become more likely since 1980 to have multiple generations in Central Europe in the same year, as a long-term warming trend has picked up pace:


Ecologist Florian Altermatt of the University of California, Davis has studied 44 species of moths and butterflies in Central Europe.  He published the results December 22 in the science journal, Proceedings of the Royal Society B article, “Climatic warming increases voltinism in European butterflies and moths” (which is available online for free for a few more days).  “Voltinism” refers to the number of breeding cycles in a year.

As the region has warmed since the 1980s, some of these species have added an extra generation during the summer for the first time on record in that location. Among the 263 species already known to have a second or third generation there during toasty times, 190 have grown more likely to do so since 1980.

Since the journal article is a tough read, I’m excerpting the Science News story (which is also the source of the pictures):

Only a rough third or so of all the species Altermatt reviewed show the capacity to breed more than once a year. What warming is probably doing for them, he speculates, is jolting the insects’ overwintering form into action early and also speeding up insect development. These head starts may allow time for a bonus generation before a non-temperature cue, atumnal day length, plays its role in shutting down insects for winter.

From a pest perspective it’s an important issue,” says population ecologist Patrick Tobin based in Morgantown, W.Va., for the Forest Service Northern Research Station. Tobin has studied a warmth-related extra generation in a North American pest, the grape berry moth. He points out that an extra surge of attacking pests in the growing season means yet another headache, expense and round of damage for farmers.

Extra insect generations are important for ecosystems too, Tobin says, though predicting those ripples of consequences will be “extraordinarily complex.” An additional generation of insects might boost a population of the predators that feed on them and thus make life tougher for the other species the predators attack. Or an extra annual generation of an endangered insect might give the species an extra push toward recovery.

When creatures manage an extra generation in a year, evolutionary processes happen faster, Altermatt says. Those species that do get an extra, successful generation win a little uptick in their chances of adapting. He’s not predicting that the effect will be enough for species to cope with widespread habitat loss or climate change, but, he says, “It’s maybe a little hope.”

Finally, some climate-changed-boosted insect population explosions are worse than others (see “Memo to Baucus: Your state’s trees are being ravaged by warming-driven pests now and Montana faces 175% to 400% increase in wildfire burn area.”

h/t Wired Science.


11 Responses to Global warming is already speeding up insect breeding

  1. Gail says:

    I think the last sentence in the article may be key:

    “’I can’t say if the generations were successful,’ he says. One peril of warming is that, when doing a little extra development, insects may not reach a winter-hardy phase.”

    I don’t know about insects, but I know birds will hatch more than one brood in a season IF the first set doesn’t live, for whatever reason. We had an evil kitty that knocked down successive nests of baby barn swallows (he could walk upside down on the roof of the loft) and the moms just keep making more, all summer long. (My daughter caught the babies from the barn floor and raised them in a garden shed, she spend months feeding ravenous baby birds.)

    And late this summer and into fall I noticed lots of little birds that couldn’t fly, they just hopped away. At first I thought they were midgets and then I realized they are babies born late.

    Since the researchers admit they are “speculating” it could be that the first sets of baby butterflies aren’t surviving, due to unknown factors, and that is what is prompting successive generations, not warming.

    As to bark beetle damage, it’s not just warming, check out the conclusions published from a conference at Duke University:

    ¨ Nitrogen saturation increases trees’ susceptibility to insects/disease.

    4) Air Pollution Effects on Forest Diseases and Pests

    ¨ Both acute and chronic episodes of acid deposition, ozone, and nitrogen can alter the incidence, epidemiology, and magnitude of tree insects and pathogens.

    ¨ Experimental and field studies have shown insects and diseases can be proximal causes of forest decline but they are also as an outcome of precursor stresses, including atmospheric deposition.

    ¨ Anthropogenic pollutant stress has been shown (in controlled experiments) to elicit plant biochemical and anatomical changes, leading to increased insect infestations and disease epidemics.”

    linked to here:

  2. derek says:

    You’re grasping at straws dude and how about a blog on all this snow the whole US has gotten maybe call it ( global snowing).

    [JR: BTDT.]

  3. mark says:

    Very interesting.

    “means yet another headache, expense and round of damage for farmers.”

    It probably also means another round of spraying pesticides on the crops to be consumed by us. And higher prices for food. and maybe less food.

    Does reproduction increase, when conditions are more difficult?

    found this: (hope you don’t mind)

    “In unstable or unpredictable environments, r-selection predominates as the ability to reproduce quickly is crucial. Traits that are thought to be characteristic of r-selection include: high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely. Organisms whose life history is subject to r-selection are often referred to as r-strategists or r-selected. Organisms with r-selected traits range from bacteria and diatoms, through insects and weeds.”

  4. Leland Palmer says:

    We’re in for a real ecological unraveling and mass extinction, no matter whether we reverse CO2 buildup in the atmosphere, or not. Even if we immediately seize every coal fired power plant worldwide, and immediately start putting carbon back underground using Biomass Energy plus Carbon Capture and Storage (BECCS), we’re still in for some ecological unraveling, I think.

    Considering the complexity of ecosystems, thinking that there will be a happy result from global heating is incredibly foolish.

    It would be like taking a finely tuned machine, and expecting a happy result from throwing sand in the works.

    How will it unfold? Impossible to predict, probably, even for professional ecologists.

    Ecosystems tend not to collapse, I think. Instead, they tend to simplify themselves to hardy species – varmints and weeds, I guess. But, there may never have been a climate change as rapid as the one we have brought upon ourselves, so, really it’s anyone’s guess how it will unfold.

    The closest historical analogue may be the End Permian Mass extinction, although that event took 80,000 years, and our coming mother of all methane catastrophes may take far less time, because of the huge systematic CO2 forcing we are adding to the first stage of the event.

    Paul Wignell of the University of Leeds, one of the gurus in this area, maintains that the plankton apparently collapsed, in the oceans. Some species survived without much problem, while 95 percent of oceanic species and 80 percent or so terrestrial species were destroyed. Of course, this catastrophe took 80,000 years, while our coming catastrophe may take, at a guess, only a couple of hundred years, due to the geologically instantaneous nature of our CO2 increase, and its sudden, systematic, and nonrandom nature.

    This is part 5 of a BBC special on the End Permian mass extinction:

    The Day the World Almost Died (part 5):

    The first four parts are really good too, and well worth watching, but the last part outlines the methane catastrophe theory of the End Permian extinction.

    They make the point in the BBC documentary that CO2 alone can only get us 5 degrees C or so of warming, at least back then. To get the End Permian sort of extinction, there would have to be another 5 degrees C or so of warming from methane hydrate dissociation.

    These sorts of considerations are why I advocate BECCS. The carbon negative effect of BECCS, done immediately and universally, worldwide, to every coal fired power plant on the planet, may be our only hope of averting the sort of ecological unraveling that we are starting to see.

  5. Dean says:

    derek said:
    December 26, 2009 at 3:30 pm

    You’re grasping at straws dude and how about a blog on all this snow the whole US has gotten maybe call it ( global snowing).

    Derek, dude, why don’t you educate yourself with regards to the basic physics involved in climate change before you look like a total idiot.

    Hint: You might want to start with the chapter that talks about warmer air having the capacity to hold more water vapor, thus generating more snow…

    After that, you might want to look into the basic difference between day-to-day “weather” and long term “climate”…

  6. David Scott says:

    I could be paddling a rowboat down Market Street in San Francisco after the poles have melted, and there will still be conservative fanatics who deny that humans are responsible for Global Warming or that it is even real. I invite you to my web-pages devoted to raising awareness on this urgent issue:

  7. jyyh says:

    Yep, that’s what happens. The amount of second broods a year in insects has been on the increase for a while in here, too. Then if the winter’s mild, they get an early start for the next year. Very nice to have this snow after a cold period since some those pesky pests (well also some nice butterflys and such) will have a hard time. Just hoping the next storm will come also as snow, since the ice crust that develops in snow when it rains mildy will put all (not just humans) larger species through a hard time, as was seen with the caribou (and reindeer) herds recently, both in Canada and northern Russia. The only ones that thrive in such conditions are voles and moles and some mice. I haven’t seen any study though on this subject, but I haven’t actually been looking.

  8. espiritwater says:

    More breeding seasons equals more bugs. Hmmm… the only thing more formidable than us humans: bugs. We humans can rape and plunder the earth all we want, wipe out other species fairly easily, but we can never erradicate our worst enemy: insects and microbes.

    Sounds like the earth is mounting a huge defense system in response to all of us humans which are giving it a fever. Considering the fact that millions of us can be wiped out with one stroke by the mighty bugs, we may want to heed this sign post warning!

  9. Leif says:

    Even the bottom of an Outhouse is utopia to some life forms, that does not mean I want to adapt.

    Hopefully some of you out there will possess a gene pool that will allow your off spring to look at a pile of excrement and sigh, this is indeed heaven on earth.

    On the other hand I prefer to think we still have some wiggle room to smell some flowers yet.

  10. Gail says:

    It turned out that this very afternoon my peacock had an opinion on this topic, which he has displayed here:

  11. Sable says:

    Many birds (esp. smaller species) have multiple broods in a season regardless of the success or failure of the first nesting. Food availability is probably the most important factor. As average temperatures keep rising in the northern hemisphere, we can expect to see continued range expansion northward of many warm adapted birds, insects, etc. and perhaps those birds species which normally attempt two broods may be more likely to try three or more.

    Nevertheless all of these animals face human caused challenges/opportunities other than warming – habitat fragmentation or destruction, and other forms of pollution chief among them. I’d bet we’ll see many species benefit in the relative short term to global warming, say for a few decades or perhaps even much longer – and then they too will be increasingly stressed into extinction.