Question regarding "Insect Apocalypse"

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Buzz Bloom

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Below are some excerpts from a news article:

https://www.nytimes.com/2018/11/27/magazine/insect-apocalypse.html .
In the United States, scientists recently found the population of monarch butterflies fell by 90 percent in the last 20 years, a loss of 900 million individuals; the rusty-patched bumblebee, which once lived in 28 states, dropped by 87 percent over the same period.
To test what had been primarily a loose suspicion of wrongness, Riis and 200 other Danes were spending the month of June roaming their country’s back roads in their outfitted cars. They were part of a study conducted by the Natural History Museum of Denmark, a joint effort of the University of Copenhagen, Aarhus University and North Carolina State University.
In Britain, as many as 30 to 60 percent of species were found to have diminishing ranges. Larger trends were harder to pin down, though a 2014 review in Science tried to quantify these declines by synthesizing the findings of existing studies and found that a majority of monitored species were declining, on average by 45 percent.
Ornithologists kept finding that birds that rely on insects for food were in trouble: eight in 10 partridges gone from French farmlands; 50 and 80 percent drops, respectively, for nightingales and turtledoves. Half of all farmland birds in Europe disappeared in just three decades.
In 2013, Krefeld entomologists confirmed that the total number of insects caught in one nature reserve was nearly 80 percent lower than the same spot in 1989.
It is estimated that, since 1970, Earth’s various populations of wild land animals have lost, on average, 60 percent of their members.
The current worldwide loss of biodiversity is popularly known as the sixth extinction: the sixth time in world history that a large number of species have disappeared in unusually rapid succession, caused this time not by asteroids or ice ages but by humans.​

I am hoping that among the PFs' participants there are some who can provide additional insights about what this article reports.


 

BillTre

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I liked your post because its important, but I also don't like it because it is one of many bad news items concerning the environment.

I have not yet read this article, but the decrease in insects is something that has been reported several times in the last year or two.
Do they mention any potential causes?

I can image:
  • climate change
  • insecticides
  • non-climate caused habitat changes (wild to agriculture, urban, or other uses)
What ever the cause, it bodes ill.
I wish my kids were going to inherit a better rather than a worse world.
 

Klystron

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I read the original New York Times article and was motivated to read the comments selected by NYT. Though mainly anecdotal a consistent pattern of loss emerged from respondents from around the globe. Species that were a common sight to adults when they were children such as robins are gone from the same locales and seasons.

As a bird enthusiast, I can relate similar anecdotes. After moving from (coastal) Santa Cruz and Santa Clara counties in Northern California to Las Vegas valley in the high Mojave desert, after 10 years I visited family in California and went to a field outside Santa Cruz where I used to hike and observe thick and numerous flocks of birds. Good season, weather, and time of day to view birds. Area had been free of development and hunting. Closest town would be Davenport; not a common tourist area.

"Where are the birds?", I asked my brother-in-law.

We startled a few birds -- mostly finches and birds of that size plus a few hummingbirds and grackles (a small corvus) -- while crossing fields but never more than a few airborne stragglers were ever in sight. Ground birds, including nests and tracks, unseen. Nearby forest had many jays but saw no robins or any other birds except grackles and two dove species.

My anecdote has no scientific validity nor was I observing insects. My normally talkative brother-in-law, always ready with the latest popular science conjecture, was silent on the subject.

--Norm
 

BillTre

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I am waiting for the opportunity to go up to a particular lake in the Upper Peninsula of Michigan for a week or two around the May/June transition.
Previously when I have been there at the time, there was a huge profusion of Mayflies (in May) and June bugs (in June). There were also particular places around the lake's shore where there clouds of mosquitoes at dusk. Also lots of bats (insectivorous).

It would be interesting to compare the numbers. I remember, looking up at the sky in May, at the edge of the lake, and seeing what I would guess were >10,000 mayflies flying around in my field of vision.
Better data could be obtained by pointing a camera straight up a taking a picture, from which a count could be taken.
Differences in apparent numbers however could conceivably be due to not a decrease in insect population numbers, but a change in timing of when in the year they emerge from their pupae and fly around looking for mates.
I would therefore want to be there for a longer period of time (2 weeks is probably max for me). Probably at slightly earlier times in the year, because I would expect an earlier spring due to global warming and the movement of climate zones northward.
 

Bystander

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non-climate caused habitat changes (wild to agriculture, urban, or other uses)
Estimates of agricultural use (single crop, minimal diversity) run from 10 to 20 percent of dry land surface area; might be we've exceeded a Malthusian limit.
 

jim mcnamara

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It is not anecdotal evidence on insect populations. It is based on longevity studies, and shows declines insect populations between 75% - 95% decline in specific species since 1975 samples taken with the same methods and and in the same places. Data shows large declines in North America and Europe. There is a huge amount of bird population estimates over long periods, ranging from Christmas counts to satellite image surveys of nesting grounds in the Arctic. Declines and extinctions are noted, example: whooping cranes. Since Cuba trashed most Northern songbird overwintering habitat on that island, the songbird populations in Central US woodlands are decimated. Another example.

Google for John Terborg on loss of songbirds technical articles. Also there is the Forest Island Effect where certain minimum sizes of contiguous forest are required for both mammal and bird species.


We had another thread, which links to both pop sci and some other more technical articles. See:
https://www.physicsforums.com/threads/insect-arthropod-and-insectivore-population-crash.957706/
 

Klystron

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I read the original New York Times article and was motivated to read the comments selected by NYT. Though mainly anecdotal a consistent pattern of loss emerged from respondents from around the globe. Species that were a common sight to adults when they were children such as robins are gone from the same locales and seasons.

As a bird enthusiast, I can relate similar anecdotes. ...[snip]
Clarification: the OP cited the NYT science article. I was referring to Times readers' comments concerning "Insect Apocalypse" not to the basis of the article. I used the term 'anecdote' for readers relating memories, often from childhood, of past abundance of insects and birds compared to present observations while outdoors. I was not criticizing data collection methods but moved by the importance of the subject to reply [for some reason I only comment in the Times on Literature.].

Another dreary observation: throughout my life (mid-20th to present) I have enjoyed Nature programs. Sometime in my childhood the narrators began adding comments at the end of the show that "the creatures you're enjoying are under pressure", progressing over the years to "these creatures are slowly disappearing and may soon become extinct".

--Norm
 

BillTre

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Here is an open access article that says about 40% of the world's insect species are threatened with extinction in the next few decades.
  • Lepidoptera (butterflies and moths), Hymenoptera (bees, ants, wasps) and dung beetles (Coleoptera) are the taxa most affected.
  • Four aquatic taxa (Odonata (dragonflies), Plecoptera (stoneflies), Trichoptera (caddisflies) and Ephemeroptera (mayflies)) are imperiled and have already lost a large proportion of species.
  • Habitat loss by conversion to intensive agriculture is the main driver of the declines.
  • Agro-chemical pollutants, invasive species and climate change are additional causes.
 
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The studies should serve as an eye opener. Let us hope we can take some measures to alleviate the negative effects presented.
 

256bits

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I used the term 'anecdote' for readers relating memories
Why not anecdotal?
I cannot remember the last time I have had to clean out my radiator and grill of bugs.
Anyone anywhere still have that "problem:.
 

gleem

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It is not only the insecticides or herbicides aimed specifically at controlling pests but other apparently benign substances as chemicals used in plastics , cleaners, fragrances, personal care products as well as pharmaceutical that people flush down the drain to protect society from unauthorized use as well as those chemicals used in the production of these products.

Substances know as endocrine disrupting chemicals such as phthalates and bisphenol A (BPA) are currently in widespread use in consumer products. Others like polychlorinated biphenyls (PCBs) used in industry have been subject to huge clean up projects due to negligent dumping of wastes. Such substances could also be having an as yet unrecognized affect on humans such as the epidemic of obesity.
 

BillTre

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I would like to propose that further posts in this important subject (insect losses and its ecological impact) be added to this thread.

This would get the subject, in general, and each post, greater context and (hopefully) greater impact.
 
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As a purely anecdotal observation, when I was a kid in the 1940's we lived a a few different places and regardless of location there were, anywhere near bodies of water, tons of dragonflies. I was, for some reason, quite taken by them, so was delighted by their multitudinous presence. Sadly, I rarely see dragonflies anywhere these days.
 

BillTre

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I really like dragonflies!
They are ancient insects. Some are reputed to have had 3 foot wingspans (higher O2 levels).
They are visual hunters of other flying insects and have high visual acuity.

Something I like about macro shots like your is that they reveal (or make visible) beauty at finer scales.
This is one of the reasons I like microscopes. Higher mags, more details.

Beautiful details, like these, can be seen, at higher powers, in all insects (and other living things).
 

gleem

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Interestingly here on the eastern shore of the Chesapeake bay I am seeing more dragonflies even though my particular area is not known for its wetlands. While the area is still being developed some wealthy landowners have let some of their agricultural property return to its natural state and have even created shallow ponds.
 

jim mcnamara

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From @BillTre:
They are ancient insects. Some are reputed to have had 3 foot wingspans (higher O2 levels).
During Carboniferous times, O2 levels in the atmosphere were higher than today. Land-based arthropods "breathe" through spiracles, largely using diffusion, a kind of passive system for respiration compared to lungs. Diffusion of O2 in lower modern levels is one of the limiting factors on the size of land-dwelling arthropods. Another is the much greater mass of exoskeleton, versus the smaller mass of an endoskeleton - reptiles, mammals, birds - for similar sized animals. If an elephant had an exoskeleton it probably could not stand up and walk without burning huge numbers of kCal of food. Maybe not even be able to stand....

Carboniferous atmosphere (not too technical article from Smithsonian): http://forces.si.edu/atmosphere/02_02_06.html
Spiracles (insects, sharks, rays - great pictures) - https://en.wikipedia.org/wiki/Spiracle
 

pinball1970

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Here's a pic I took of one and a closeup of a wing area. They are beautiful creatures, I think, and the world will be a lesser place if they disappear.

View attachment 238865

View attachment 238866
Beautiful and totally terrifying to me.


This paper looks at the effect of temperature on the ability to reproduce.


https://onlinelibrary.wiley.com/doi/full/10.1111/jeb.13018


Also this (if you can deal with the “Proof”) Jim/Bill mentioned climate change


https://www.researchgate.net/publication/326649710_Emerging_insect_pests_in_Indian_agriculture


Anecdotal – we (royal) have reported increases of “some” species in Asia (vague I know)
 

pinball1970

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It is not only the insecticides or herbicides aimed specifically at controlling pests but other apparently benign substances as chemicals used in plastics , cleaners, fragrances, personal care products as well as pharmaceutical that people flush down the drain to protect society from unauthorized use as well as those chemicals used in the production of these products.

Substances know as endocrine disrupting chemicals such as phthalates and bisphenol A (BPA) are currently in widespread use in consumer products. Others like polychlorinated biphenyls (PCBs) used in industry have been subject to huge clean up projects due to negligent dumping of wastes. Such substances could also be having an as yet unrecognized affect on humans such as the epidemic of obesity.
I am not convinced there is an obesity epidemic because of endocrine disrupters or “viruses” that have also been reported.


“Eco textiles” names and shames these chemicals on a regular basis


https://oecotextiles.wordpress.com/2013/04/11/endocrine-disruptors-in-fabric/


If chemicals used industry are having the effect on insect populations that is reported, I hope we are not too late cleaning the mess up before we lose species.
 
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I always get a little irritated when I see words like Apocalypse and Armageddon used in articles, particularly when linked to ecology. The first thing to consider is the quality of the evidence, which isn't really that impressive, its suggested that we have only identified around a fifth of the species and we have very poor baseline data. One of the problems in the study of insects is the degree of specialisation in some species, its likely that small environmental changes and shifts towards monoculture may have a massive effect on some species. I know people have outlined their own experiences but something I haven't seen is a mention of huge swarms of some insects, in the UK we were swamped with continental ladybirds last summer, which are of course predators. There have also been significant recovery of pollinator species despite attempts by some groups to use the decline to ban certain insecticides, with little evidence. This is one of those issues that need to be investigated properly without it drifting into other alarmist stories. I say this because if there really is a mass insect extinction taking place the effects that this would have on the ecosystem would make every other alarmist message irrelevant, the effect on agriculture really would make this a global disaster. The first link discusses some of the research and the second tries to bring a bit of realism to the discussion.
https://ecologyisnotadirtyword.com/2019/02/16/insectageddon-is-a-great-story-but-what-are-the-facts/
https://www.theatlantic.com/science/archive/2019/02/insect-apocalypse-really-upon-us/583018/
 
I always get a little irritated when I see words like Apocalypse and Armageddon used in articles, particularly when linked to ecology. The first thing to consider is the quality of the evidence, which isn't really that impressive, its suggested that we have only identified around a fifth of the species and we have very poor baseline data. One of the problems in the study of insects is the degree of specialisation in some species, its likely that small environmental changes and shifts towards monoculture may have a massive effect on some species. I know people have outlined their own experiences but something I haven't seen is a mention of huge swarms of some insects, in the UK we were swamped with continental ladybirds last summer, which are of course predators. There have also been significant recovery of pollinator species despite attempts by some groups to use the decline to ban certain insecticides, with little evidence. This is one of those issues that need to be investigated properly without it drifting into other alarmist stories. I say this because if there really is a mass insect extinction taking place the effects that this would have on the ecosystem would make every other alarmist message irrelevant, the effect on agriculture really would make this a global disaster. The first link discusses some of the research and the second tries to bring a bit of realism to the discussion.
https://ecologyisnotadirtyword.com/2019/02/16/insectageddon-is-a-great-story-but-what-are-the-facts/
https://www.theatlantic.com/science/archive/2019/02/insect-apocalypse-really-upon-us/583018/
Healthy skeptisicm is a good thing.
Adding too many grains of salt or attempting to find an angle doesn't work out too well. For example, as testing of substances go it is not smart to think any effect is really unimpactful if the usage is very high.

Lack of data is not an excuse, it should be an invitation!

Thanks for those articles.
 
I live in a very buggy area in North Carolina... actually the entire state is pretty buggy. But over the past two years I've noticed the total bug count plummeting. We used to have large numbers of butterflies, of 7-8 species. Now each summer day, maybe 2-3 individuals. Used to be, bumble bees, carpenter bees, honey bees, ground-dwelling bees, yellow jackets, paper wasps & mud daubers in abundance. Now? This past year, only one colony of any such social insects.

Ants are down, as are dragon flies and damsel flies. Amazingly, no more mosquitos! And even though I have lots of deer on the property, only 1-2 deer ticks, the entire season. We used to be covered in them. Also used to have many spiders of all sorts. Now hardly a one. Nor moths, nor millipedes, nor daddy longlegs. Naturally our frogs, box turtles, skinks, anoles and geckos have also disappeared. All were abundant 3 years ago.

Nothing has changed as far as neighbors spraying for insects. If anything, we have fewer farms around than previously. The only significant change in the environment has been the conversion of wooded areas and old farms into newly landscaped developments. So the only guess I can make is habitat loss. It's very disturbing, and I wonder if others living in rural areas being converted into suburbs are seeing the same thing.
 

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