Decline of insect populations — an existential hazard?

14 February 2019

Evolutionary genetics made us short-sighted

That trait is likely to force Homo sapiens' demise, within our biospherically closed Earth system.

For instance

The Lamestream has not made significantly much of recent scientific reports like these two:

Bradford C. Lister and Andres Garcia, Climate-driven declines in arthropod abundance restructure a rainforest food web, PNAS [Proceedings of the National Academy of Sciences] 115 (44) E10397-E10406 (30 October 2018 — published ahead of print, 15 October 2018) (https://doi.org/10.1073/pnas.1722477115)

Francisco Sánchez-Bayo and Kris A.G. Wyckhuys, Worldwide decline of the entomofauna: A review of its drivers, Biological Conservation (volume 232, April 2019) (at pages 8-27)

Consider implications

From the first report:

Here we analyze data on arthropod and insectivore abundances taken between 1976 and 2012 at two midelevation habitats in Puerto Rico’s Luquillo rainforest.

During this time, mean maximum temperatures have risen by 2.0 °C. Using the same study area and methods employed by Lister in the 1970s, we discovered that the dry weight biomass of arthropods captured in sweep samples had declined 4 to 8 times, and 30 to 60 times in sticky traps.

© 2018 Bradford C. Lister and Andres Garcia, Climate-driven declines in arthropod abundance restructure a rainforest food web, PNAS [Proceedings of the National Academy of Sciences] 115 (44) E10397-E10406 (30 October 2018 — published ahead of print, 15 October 2018) (https://doi.org/10.1073/pnas.1722477115) (at Abstract)

And from the second:

Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers.

Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades.

The main drivers of species declines appear to be in order of importance:

i) habitat loss and conversion to intensive agriculture and urbanisation;

ii) pollution, mainly that by synthetic pesticides and fertilisers;

iii) biological factors, including pathogens and introduced species;

and

iv) climate change.

The latter factor is particularly important in tropical regions, but only affects a minority of species in colder climes and mountain settings of temperate zones.

A rethinking of current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices, is urgently needed to slow or reverse current trends, allow the recovery of declining insect populations and safeguard the vital ecosystem services they provide.

In addition, effective remediation technologies should be applied to clean polluted waters in both agricultural and urban environments.

© 2019 Francisco Sánchez-Bayo and Kris A.G. Wyckhuys, Worldwide decline of the entomofauna: A review of its drivers, Biological Conservation (volume 232, April 2019) (pages 8-27) (at Abstract) (reformatted for online clarity)

Two legs and six

Insects are important to the web of life.

When we have successfully killed off roughly 40 percent of their species, something's "gonna" give.

The result may (and probably will) be more massively unfortunate for us, than just the planetary warming that some people are, probably intelligently, freaking out about.

Environmentalist Joe Romm put the insect situation into perspective

He wrote that:

The global insect population outweighs all of humanity by a margin of 17 to 1, but humans are on track to wipe insects out in a matter of decades, according to the first worldwide review of insect decline.

This would be doubly catastrophic.

First, losing the insects means losing the animals that feed on them, thus shattering the entire ecosystem.

Second, losing the insects — which pollinate plants and keep the soil healthy — would devastate agriculture and our ability to feed a rapidly growing population.

A personal observation

I lived on a Colorado farm for decades. Watching plants, animals and seasonal cycles were the norm.

Recently, during a three-year assignment in Germany, I was surprised by the virtual lack of insects in the rural location where we lived. There were also comparatively few birds and small mammals.

The environment there felt out of kilter. I even missed mosquitoes.

The feeling was similar to that occasioned by hours long wind lapses in Wyoming. You know that something is out of whack, but have difficulty recognizing what it is.

The moral? — I'm not a catastrophist, but insect disappearances seem to pose a brewing disaster

Humanity is completely dependent upon general parameters of the environments that spawned us.

I suspect that our inbred penchant for ignoring anything that is not threatening just this second — is cumulatively going to do us in.

Afterward, new "somebodies" may have the opportunity to name another geological age. Homo sapiens' non-illustrious departure will have become part of Time's natural flow. Our vanished selves may hear the metaphorical cackle of myriad plants and critters that we did in along the way.

Is this anthropomorphization?

That will be over, too.

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Decline of insect populations — an existential hazard?